Cardiac Arrest

Brief HPI:

An overhead page alerts you to an arriving patient with cardiac arrest. An approximately 35-year-old male was running away from police officers and collapsed after being shot with a stun gun. The patient was found to be pulseless, CPR was started by police officers and the patient is en route.

An Algorithm for the Evaluation and Management of Cardiac Arrest with Ultrasonography

An Algorithm for the Evaluation and Management of Cardiac Arrest with Ultrasonography

Causes of Cardiac (and non-cardiac) Arrest

Sudden cardiac arrest (SCA) leading to sudden cardiac death (SCD) if not successfully resuscitated, refers to the unexpected collapse of circulatory function. Available epidemiologic data for in-hospital and out-of-hospital cardiac arrest (OHCA) point appropriately to cardiac processes as the most common cause, though extra-cardiac processes (most frequently respiratory), comprise up to 40% of cases1-3.

Identifying the underlying cause is critical as several reversible precipitants require rapid identification. However, the usual diagnostic techniques may be challenging, limited or absent – including patient history, detailed examination, and diagnostic studies.

The initial rhythm detected upon evaluation is most suggestive of the etiologic precipitant. Pulseless ventricular tachycardia (pVT) or ventricular fibrillation (VF) is suggestive of a cardiac process – most commonly an acute coronary syndrome although heart failure or other structural and non-structural heart defects associated with dysrhythmias may be at fault4.

Pulseless electrical activity (PEA) presents a broader differential diagnosis as it essentially represents severe shock. The most common extra-cardiac cause is hypoxia – commonly secondary to pulmonary processes including small and large airway obstruction (bronchospasm, aspiration, foreign body, edema). Other causes include substance intoxication, medication adverse effect5,6, or electrolyte disturbances7. Finally, any precipitant of shock may ultimately lead to PEA, including hypovolemia/hemorrhage, obstruction (massive pulmonary embolus8, tamponade, tension pneumothorax), and distribution (sepsis).

Asystole is the absence of even disorganized electrical discharge and is the terminal degeneration of any of the previously-mentioned rhythms if left untreated.

Management of Cardiac Arrest

Optimizing survival outcomes in patients with cardiac arrest is dependent on early resuscitation with the prioritization of interventions demonstrated to have survival benefit. When advanced notice is available, prepare the resuscitation area including airway equipment (with adjuncts to assist ventilation and waveform capnography devices). Adopt the leadership position and assign roles for chest compressions, airway support, application of monitor/defibrillator, and establishment of peripheral access.

High-quality chest compressions with minimal interruptions are the foundation of successful resuscitation – and guideline changes prioritizing compressions have demonstrated detectable improvements in rates of successful resuscitation9,10. Measurement of quantitative end-tidal capnography can guide adequacy of chest compressions11,12 and an abrupt increase may signal restoration of circulation without necessitating interruptions of chest compressions13,14. Sustained, low measures of end-tidal CO2 despite appropriate resuscitation may signal futility and (alongside other factors) guides termination of resuscitation11,12.

The next critical step in restoring circulation is prompt defibrillation of eligible rhythms (pVT/VF) when detected. The immediate delivery of 200J (uptitrated to the device maximum for subsequent shocks) of biphasic energy and restoration of a perfusing rhythm is one of few interventions with clear benefits. For pVT/VF that persists despite multiple countershocks (more than three), the addition of an intravenous antiarrhythmic appears to improve survival to hospital admission. The ARREST trial was a randomized controlled study comparing amiodarone to its diluent as placebo for OHCA with refractory pVT/VF showing significant improvement in survival to hospital admission for the amiodarone group15. This was followed by the ALIVE trial comparing amiodarone and lidocaine which showed significantly higher rates of survival to hospital admission in the amiodarone group16. However, a more recent randomized trial comparing amiodarone (in a novel diluent less likely to cause hypotension), lidocaine, and placebo in a similar patient population showed less convincing results, with no detected difference in survival or the secondary outcome of favorable neurological outcome for either amiodarone or lidocaine compared with placebo17. The heterogeneity of available data contributed to current guidelines which recommend that either amiodarone or lidocaine may be used for shock-refractory pVT/VF18.

Current guidelines also recommend the administration of vasopressors (epinephrine 1mg every 3-5 minutes). In one randomized controlled trial exploring the long-standing guideline recommendations, epinephrine was associated with increased rates of restoration of spontaneous circulation, though no significant impact on the primary outcome of survival to hospital discharge was identified19. Physiologically, increased systemic vascular resistance combined with positive beta-adrenergic impact on cardiac output would be expected to complement resuscitative efforts. However, more recent studies have suggested that arrest physiology and unanticipated pharmacologic effects may complicate this simplistic interpretation – particularly when patient-centered outcomes are emphasized. Research exploring the timing and amount of epinephrine suggest that earlier administration and higher cumulative doses are associated with negative impacts on survival to hospital discharge and favorable neurological outcomes20-22.

Ultimately, treatment should focus on optimal execution of measures with clear benefits (namely chest compressions and early defibrillation of eligible rhythms). Other management considerations with which the emergency physician is familiar with including establishing peripheral access and definitive airway management can be delayed.

Rapid Diagnostic Measures for the Identification of Reversible Processes

Traditional diagnostic measures are generally unavailable during an ongoing cardiac arrest resuscitation. The emergency medicine physician must rely on the physical examination and point-of-care tests with the objective of identifying potentially reversible processes. Measurement of capillary blood glucose can exclude hypoglycemia as a contributor. Point-of-care chemistry and blood gas analyzers can identify important electrolyte derangements, as well as clarifying the primary impulse in acid-base disturbances.

End-tidal capnography was discussed previously for the guidance of ongoing resuscitation, but it may have diagnostic utility in patients with SCD. In one study the initial EtCO2 was noted to be significantly higher for primary pulmonary processes (with PEA/asystole as presenting rhythm) compared to primary cardiac processes (with pVT/VF as presenting rhythm)23.

The use of point-of-care ultrasonography, particularly in PEA arrest where non-cardiac etiologies dominate, may help identify the etiology of arrest and direct therapy. Bedside ultrasonography should be directed first at assessment of cardiac function – examining the pericardial sac and gross abnormalities in chamber size. A pericardial effusion may suggest cardiac tamponade, ventricular collapse can be seen with hypovolemia, and asymmetric right-ventricular dilation points to pulmonary embolus where thrombolysis should be considered8. If cardiac ultrasound is unrevealing, thoracic ultrasound can identify pneumothorax24-27.

In the absence of ultrasonographic abnormalities, attention turns to other rapidly reversible precipitants first. If opioid toxicity is a consideration, an attempt at reversal with naloxone has few adverse effects. If any detected rhythm is a polymorphic ventricular tachycardia characteristic of torsades de pointes – rapid infusion of magnesium sulfate should follow defibrillation. Other potentially reversible medications or toxins should be managed as appropriate.

Post-Resuscitation Steps

After successful restoration of circulation, the next management steps are critical to the patient’s long-term outcomes. A definitive airway should be established if not already secured (and if restoration of circulation was not associated with neurological recovery sufficient for independent airway protection). Circulatory support should continue with fluid resuscitation and vasopressors to maintain end-organ perfusion.

An immediate ECG should be performed to identify infarction, ischemia or precipitants of dysrhythmia. ST-segment elevation after return of spontaneous circulation (ROSC) warrants emergent angiography and possible intervention. However, given the prevalence of cardiac causes (of which coronary disease is most common) for patients with pVT/VF arrest, the presence of ST elevations is likely of insufficient sensitivity to identify all patients who would benefit from angiography. Several studies and meta-analyses have explored a more inclusive selection strategy for angiography (patients without obvious non-cardiac causes for arrest), all of which identified survival benefits with angiography and successful angioplasty when possible28-30.

Finally, the induction of hypothermia (or targeted temperature management) has significant benefits in survivors of cardiac arrest and can be instituted in the emergency department. Studies first targeted a core temperature of 32-24°C, with a randomized controlled trial demonstrating higher rates of favorable neurological outcome and reduced mortality31. More recent studies suggest that a more liberal temperature target does not diffuse the positive effects of induced hypothermia. A randomized trial of 939 patients with OHCA comparing a targeted temperature of 33°C vs 36°C suggested that a lower temperature target did not confer higher benefit to mortality or recovery of neurological function32. The more liberal temperature target may alleviate adverse effects associated with hypothermia which include cardiovascular effects (bradycardia), electrolyte derangements (during induction and rewarming), and possible increased risk of infections33. Targeted temperature management is achieved with external cooling measures or infusion of cooled fluids, rarely requiring more invasive measures34. Aggregate review of available data in a recent meta-analysis further supports the use of targeted temperature management after cardiac arrest as standard-of-care35.

References

  1. Bergum D, Nordseth T, Mjølstad OC, Skogvoll E, Haugen BO. Causes of in-hospital cardiac arrest – Incidences and rate of recognition. Resuscitation. 2015;87:63-68. doi:10.1016/j.resuscitation.2014.11.007.
  2. Wallmuller C, Meron G, Kurkciyan I, Schober A, Stratil P, Sterz F. Causes of in-hospital cardiac arrest and influence on outcome. Resuscitation. 2012;83(10):1206-1211. doi:10.1016/j.resuscitation.2012.05.001.
  3. Vaartjes I, Hendrix A, Hertogh EM, et al. Sudden death in persons younger than 40 years of age: incidence and causes. European Journal of Cardiovascular Prevention & Rehabilitation. 2009;16(5):592-596. doi:10.1097/HJR.0b013e32832d555b.
  4. Zheng ZJ, Croft JB, Giles WH, Mensah GA. Sudden cardiac death in the United States, 1989 to 1998. Circulation. 2001;104(18):2158-2163.
  5. Hoes AW, Grobbee DE, Lubsen J, Man in ‘t Veld AJ, van der Does E, Hofman A. Diuretics, beta-blockers, and the risk for sudden cardiac death in hypertensive patients. Ann Intern Med. 1995;123(7):481-487.
  6. Siscovick DS, Raghunathan TE, Psaty BM, et al. Diuretic therapy for hypertension and the risk of primary cardiac arrest. N Engl J Med. 1994;330(26):1852-1857. doi:10.1056/NEJM199406303302603.
  7. Gettes LS. Electrolyte abnormalities underlying lethal and ventricular arrhythmias. Circulation. 1992;85(1 Suppl):I70-I76.
  8. Kürkciyan I, Meron G, Sterz F, et al. Pulmonary embolism as a cause of cardiac arrest: presentation and outcome. Arch Intern Med. 2000;160(10):1529-1535.
  9. Callaway CW, Soar J, Aibiki M, et al. Part 4: Advanced Life Support: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. In: Vol 132. American Heart Association, Inc.; 2015:S84-S145. doi:10.1161/CIR.0000000000000273.
  10. Kudenchuk PJ, Redshaw JD, Stubbs BA, et al. Impact of changes in resuscitation practice on survival and neurological outcome after out-of-hospital cardiac arrest resulting from nonshockable arrhythmias. Circulation. 2012;125(14):1787-1794. doi:10.1161/CIRCULATIONAHA.111.064873.
  11. Touma O, Davies M. The prognostic value of end tidal carbon dioxide during cardiac arrest: a systematic review. Resuscitation. 2013;84(11):1470-1479. doi:10.1016/j.resuscitation.2013.07.011.
  12. Levine RL, Wayne MA, Miller CC. End-tidal carbon dioxide and outcome of out-of-hospital cardiac arrest. N Engl J Med. 1997;337(5):301-306. doi:10.1056/NEJM199707313370503.
  13. Garnett AR, Ornato JP, Gonzalez ER, Johnson EB. End-tidal carbon dioxide monitoring during cardiopulmonary resuscitation. JAMA. 1987;257(4):512-515.
  14. Falk JL, Rackow EC, Weil MH. End-tidal carbon dioxide concentration during cardiopulmonary resuscitation. N Engl J Med. 1988;318(10):607-611. doi:10.1056/NEJM198803103181005.
  15. Kudenchuk PJ, Cobb LA, Copass MK, et al. Amiodarone for resuscitation after out-of-hospital cardiac arrest due to ventricular fibrillation. N Engl J Med. 1999;341(12):871-878. doi:10.1056/NEJM199909163411203.
  16. Dorian P, Cass D, Schwartz B, Cooper R, Gelaznikas R, Barr A. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 2002;346(12):884-890. doi:10.1056/NEJMoa013029.
  17. Kudenchuk PJ, Brown SP, Daya M, et al. Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2016;374(18):1711-1722. doi:10.1056/NEJMoa1514204.
  18. Neumar RW, Shuster M, Callaway CW, et al. Part 1: Executive Summary: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. In: Vol 132. American Heart Association, Inc.; 2015:S315-S367. doi:10.1161/CIR.0000000000000252.
  19. Jacobs IG, Finn JC, Jelinek GA, Oxer HF, Thompson PL. Effect of adrenaline on survival in out-of-hospital cardiac arrest: A randomised double-blind placebo-controlled trial. Resuscitation. 2011;82(9):1138-1143. doi:10.1016/j.resuscitation.2011.06.029.
  20. Hagihara A, Hasegawa M, Abe T, Nagata T, Wakata Y, Miyazaki S. Prehospital epinephrine use and survival among patients with out-of-hospital cardiac arrest. JAMA. 2012;307(11):1161-1168. doi:10.1001/jama.2012.294.
  21. Dumas F, Bougouin W, Geri G, et al. Is epinephrine during cardiac arrest associated with worse outcomes in resuscitated patients? J Am Coll Cardiol. 2014;64(22):2360-2367. doi:10.1016/j.jacc.2014.09.036.
  22. Andersen LW, Kurth T, Chase M, et al. Early administration of epinephrine (adrenaline) in patients with cardiac arrest with initial shockable rhythm in hospital: propensity score matched analysis. BMJ. 2016;353:i1577. doi:10.1136/bmj.i1577.
  23. Grmec S, Lah K, Tusek-Bunc K. Difference in end-tidal CO2 between asphyxia cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest in the prehospital setting. Crit Care. 2003;7(6):R139-R144. doi:10.1186/cc2369.
  24. Rose JS, Bair AE, Mandavia D, Kinser DJ. The UHP ultrasound protocol: a novel ultrasound approach to the empiric evaluation of the undifferentiated hypotensive patient. American Journal of Emergency Medicine. 2001;19(4):299-302. doi:10.1053/ajem.2001.24481.
  25. Hernandez C, Shuler K, Hannan H, Sonyika C, Likourezos A, Marshall J. C.A.U.S.E.: Cardiac arrest ultra-sound exam—A better approach to managing patients in primary non-arrhythmogenic cardiac arrest. Resuscitation. 2008;76(2):198-206. doi:10.1016/j.resuscitation.2007.06.033.
  26. Chardoli M, Heidari F, Shuang-ming S, et al. Echocardiography integrated ACLS protocol versus con- ventional cardiopulmonary resuscitation in patients with pulseless electrical activity cardiac arrest. Chinese Journal of Traumatology. 2012;15(5):284-287. doi:10.3760/cma.j.issn.1008-1275.2012.05.005.
  27. Zengin S, Yavuz E, Al B, et al. Benefits of cardiac sonography performed by a non-expert sonographer in patients with non-traumatic cardiopulmonary arrest. Resuscitation. 2016;102:105-109. doi:10.1016/j.resuscitation.2016.02.025.
  28. Spaulding CM, Joly LM, Rosenberg A, et al. Immediate coronary angiography in survivors of out-of-hospital cardiac arrest. N Engl J Med. 1997;336(23):1629-1633. doi:10.1056/NEJM199706053362302.
  29. Dumas F, Cariou A, Manzo-Silberman S, et al. Immediate Percutaneous Coronary Intervention Is Associated With Better Survival After Out-of-Hospital Cardiac Arrest: Insights From the PROCAT (Parisian Region Out of Hospital Cardiac Arrest) Registry. Circulation: Cardiovascular Interventions. 2010;3(3):200-207. doi:10.1161/CIRCINTERVENTIONS.109.913665.
  30. Millin MG, Comer AC, Nable JV, et al. Patients without ST elevation after return of spontaneous circulation may benefit from emergent percutaneous intervention: A systematic review and meta-analysis. Resuscitation. 2016;108:54-60. doi:10.1016/j.resuscitation.2016.09.004.
  31. Hypothermia after Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med. 2002;346(8):549-556. doi:10.1056/NEJMoa012689.
  32. Nielsen N, Wetterslev J, Cronberg T, et al. Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest. N Engl J Med. 2013;369(23):2197-2206. doi:10.1056/NEJMoa1310519.
  33. Polderman KH, Peerdeman SM, Girbes AR. Hypophosphatemia and hypomagnesemia induced by cooling in patients with severe head injury. J Neurosurg. 2001;94(5):697-705. doi:10.3171/jns.2001.94.5.0697.
  34. Polderman KH, Herold I. Therapeutic hypothermia and controlled normothermia in the intensive care unit: Practical considerations, side effects, and cooling methods*. Critical Care Medicine. 2009;37(3):1101-1120. doi:10.1097/CCM.0b013e3181962ad5.
  35. Schenone AL, Cohen A, Patarroyo G, et al. Therapeutic hypothermia after cardiac arrest: A systematic review/meta-analysis exploring the impact of expanded criteria and targeted temperature. Resuscitation. 2016;108:102-110. doi:10.1016/j.resuscitation.2016.07.238.

Palpitations

Brief H&P

48F with a history of Grave disease (off medications for 4 months), presenting with palpitations. Noted gradual onset of palpitations while at rest, describing a pounding sensation lasting 3-4 hours and persistent (though improved) on presentation. Symptoms not associated with chest pain, shortness of breath, loss of consciousness, nor triggered by exertion. She reported a history of 8-10 episodes in the past for which she did not seek medical attention. Review of systems notable only for heat intolerance.

On physical examination, vital signs were notable for tachycardia (HR 138bpm). No alteration in mental status, murmur, tremor or hyperreflexia appreciated.

Labs

  • Hb: 14.7
  • Urine hCG: negative
  • TSH: <0.01
  • Total T3: 311ng/dL
  • Free T4: 2.64ng/dL

ECG

Palpitations - Sinus Tachycardia

Sinus Tachycardia

Impression/Plan

Palpitations due to sinus tachycardia from symptomatic hyperthyroidism secondary to medication non-adherence. Improved with propranolol, discharged with methimazole and PMD follow-up.

Differential Diagnosis of Palpitations1, 2

Differential Diagnosis of Palpitations

Evaluation of Palpitations

History and Physical

Subjective description of symptom quality
Rapid and regular beating suggests paroxysmal SVT or VT. Rapid and irregular beating suggests atrial fibrillation, atrial flutter, or variable conduction block.
Stop/start sensation: PAC or PVC
Rapid fluttering: Sustained supraventricular or ventricular tachycardia
Pounding in neck: Produced by canon A waves from AV dissociation (VT, complete heart block, SVT)
Onset and offset
Random, episodic, lasting instants: Suggests PAC or PVC
Gradual onset and offset: Sinus tachycardia
Abrupt onset and offset: SVT or VT
Syncope
Suggests hemodynamically significant arrhythmia, often VT
Examination
Identify evidence of structural, valvular heart disease

ECG1

ECG Finding Presumed etiology
Short PR, Delta waves WPW, AVRT
LAA, LVH Atrial fibrillation
PVC, BBB Idiopathic VT
Q-waves Prior MI, VT
QT-prolongation VT (polymorphic)
LVH, septal Q-waves HCM
Blocks  

Algorithm for the Evaluation of Palpitations3

Algorithm for the Evaluation of Palpitations

References

  1. Zimetbaum P, Josephson ME. Evaluation of patients with palpitations. N Engl J Med. 1998;338(19):1369-1373. doi:10.1056/NEJM199805073381907.
  2. Probst MA, Mower WR, Kanzaria HK, Hoffman JR, Buch EF, Sun BC. Analysis of emergency department visits for palpitations (from the National Hospital Ambulatory Medical Care Survey). The American Journal of Cardiology. 2014;113(10):1685-1690. doi:10.1016/j.amjcard.2014.02.020.
  3. Abbott AV. Diagnostic approach to palpitations. Am Fam Physician. 2005;71(4):743-750.

Nonsustained Ventricular Tachycardia

Case 1

64M with a history of HFrEF (LVEF 20-25%), CAD, AICD (unknown indication), COPD, CKD III presenting with gradual onset shortness of breath, progressive bilateral lower extremity edema.
Examination consistent with severe acute decompensated heart failure presumed secondary to left ventricular dysfunction.
Telemetry monitoring with multiple episodes of nonsustained ventricular tachycardia.

In the ED, the patient developed worsening respiratory failure despite initiation of therapy, requiring endotracheal intubation. Continuous cardiac monitoring revealed persistent salvos of NSVT, progressing to slow ventricular tachycardia without device intervention.
Device interrogation revealed multiple events, 3 shocks, several ATP’s over the recorded period.

Evaluation and Management:

  • NSVT with known (severe) ischemic heart disease
  • For repetitive monomorphic ventricular tachycardia: amiodarone, beta-blockade (if tolerated), procainamide (IIA, C)1

ECG’s

ECG 1
ECG 1

ECG 1

Non-specific IVCD, LAA, VPC

ECG 2
ECG 2

ECG 2

VT initiated by fusion complex

Case 2

31F with autoimmune polyglandular syndrome (adrenal, thyroid and endocrine pancreatic insufficiency), presenting with fever and cough.
Evaluation consistent with sepsis presumed secondary to pulmonary source.
Telemetry monitoring initially with ventricular bigeminy, then nonsustained ventricular tachycardia.

In the ED, the patient developed pulseless ventricular tachycardia – apparently polymorphic. Chest compressions and epinephrine produced return of spontaneous circulation with recovery to baseline neurologic function.
ECG revealed prolonged QTc and chemistry panel notable for critical hypokalemia/hypomagnesemia.

Evaluation and Management:

  • NSVT progressing to VT
  • Initially attributed to electrolyte disturbances. However, serial ECG’s continued to show prolonged QTc (possibly acquired, home medications included metoclopramide and erythromycin). Early echocardiography demonstrated global hypokinesis with EF 30-35% attributed to severe sepsis and recurrent defibrillation. Cardiac CT after resolution of acute illness showed persistently depressed ejection fraction without coronary atherosclerosis. The presence of NICM associated with malignant dysrhythmias warranted ICD placement.
  • Cardioversion for hemodynamic compromise (I, B), B-blockade (I, B), amiodarone if no LQTS (I, C), urgent angiography if ischemia not excluded (I, C)1
  • Correction of electrolyte abnormalities (specifically hypokalemia) may decrease progression to VF.2

ECG’s

ECG 1
ECG 1

ECG 1

Ventricular bigeminy

ECG 2
ECG 2

ECG 2

Long-QT

VT on Telemetry
VT on Telemetry

VT on Telemetry

Non-sustained ventricular tachycardia noted on telemetry monitoring

Definition3,4

  • > 3-5 consecutive beats originating below the AV node
  • Rate > 100bpm
  • Duration <30s

Epidemiology3,5

  • Occurs in 0-4% of ambulatory patients
  • Increased frequency in males and with increasing age
  • In some patients, NSVT is associated with an increased risk of sustained tachyarrhythmias and sudden cardiac death. In others it is of little prognostic significance.6,7,8

Evaluation

In all patients:
History: including arrhythmogenic medications/substances, pertinent family history
Physical examination
ECG/CXR
TTE
In selected patients:
Exercise testing
Advanced imaging (CT/C-MR)
Electrophysiologic studies
Genetic testing

NSVT in the absence of structural heart disease

NSVT in Idiopathic Ventricular Tachycardia

Ventricular outflow arrhythmias:
RVOT: 70-80%, LBBB pattern
LVOT: 20-30%, RBBB pattern
Mechanism:
Adrenergically mediated
Occur during exercise, resolve as heart-rate increases, recur during recovery
Management:
Exclude arrhythmogenic right ventricular cardiomyopathy (imaging, myocardial biopsy)
If symptomatic, beta-blockade, ± IC anti-arrhythmic, CCB (verapamil) for ILVT
Prognosis:
Good, rare tachycardia-induced cardiomyopathy, rare SCD

NSVT in Polymorphic Ventricular Tachycardia

Mechanism
LQTS (acquired or inherited)
Familial catecholaminergic polymorphic VT
Management
Symptomatic (ex. syncope, cardiac arrest): ICD
Asymptomatic QTc > 550ms: consider ICD
Prognosis
Increased risk SCD

Arrhythmogenic Right Ventricular Cardiomyopathy

Mechanism
Fibrosis, fibro-fatty replacement of myocardium in RVIT/RVOT/RV apex
May occur with only subtle structural abnormalities of the right ventricle
LBBB morphology
Management
Anti-arrhythmics of limited utility
Catheter ablation, ICD backup
Prognosis
Increased risk SCD

NSVT with apparent structural heart disease1

Hypertension and LVH

Mechanism
Stretch-induced abnormal automaticity
Fibrotic tissue
Presence of NSVT correlates with degree of hypertrophy and subendocardial fibrosis
Management
Evaluation for ischemic heart disease
Aggressive medical management of hypertension (including beta-blockade)
Prognosis
Unclear

Valvular Disease

Mechanism
High incidence in AS, severe MR (25%)
Mechanical stress from dysfunctional valvular apparatus
Management
Beta-blockade if symptomatic
Prognosis
No evidence that NSVT is an independent predictor of SCD.

Ischemic Heart Disease9-14

Mechanism
Monomorphic VT associated with re-entry at the borders of ventricular scars
Ischemia induces polymorphic NSVT/VF
Management
Revascularization, beta-blockade, statin, ACE/ARB
MADIT I, MUSTT: ICD for ICM LVEF <40%, NSVT, EPS inducible VT
MADIT II, SCD-HeFT: ICD for moderate-to-severe LV dysfunction irrespective of NSVT or EPS findings
Prognosis
NSTEMI with NSVT >48h after admission 2x risk SCD (MERLIN-TIMI 36)
STEMI with NSVT common, not as predictive of ACM or SCD as LVEF (CARISMA)
NSVT <24h after admission for NSTEMI/STEMI not of prognostic significance.

Hypertrophic Cardiomyopathy

Mechanism
Genetic myocardial disease
Myocyte disarray, fibrosis, ischemia result in arrhythmogenic substrate
Management
Restriction of physical activity
ICD (NSVT, LV thickness, FH SCD, syncope, abnormal BP response to exercise)
Beta-blockade, anti-arrhythmic for symptoms
Prognosis
Increased risk SCD (1% annual)

Other Conditions

  • Non-ischemic dilated cardiomyopathy
  • Giant-cell myocarditis
  • Repaired TOF
  • Amyloidosis
  • Sarcoidosis
  • Chagas cardiomyopathy

Algorithm for the Evaluation of NSVT1

Algorithm for the Evaluation of Nonsustained Ventricular Tachycardia

References

  1. Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death–executive summary: A report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death) Developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Eur Heart J. 2006;27(17):2099–2140. doi:10.1093/eurheartj/ehl199.
  2. Higham PD, Adams PC, Murray A, Campbell RW. Plasma potassium, serum magnesium and ventricular fibrillation: a prospective study. Q J Med. 1993;86(9):609–617.
  3. Katritsis DG, Zareba W, Camm AJ. Nonsustained ventricular tachycardia. J Am Coll Cardiol. 2012;60(20):1993–2004. doi:10.1016/j.jacc.2011.12.063.
  4. Katritsis DG, Camm AJ. Nonsustained ventricular tachycardia: where do we stand? Eur Heart J. 2004;25(13):1093–1099. doi:10.1016/j.ehj.2004.03.022.
  5. Wellens HJ. Electrophysiology: Ventricular tachycardia: diagnosis of broad QRS complex tachycardia. Heart. 2001;86(5):579–585.
  6. Buxton AE, Lee KL, Fisher JD, Josephson ME, Prystowsky EN, Hafley G. A randomized study of the prevention of sudden death in patients with coronary artery disease. Multicenter Unsustained Tachycardia Trial Investigators. N Engl J Med. 1999;341(25):1882–1890. doi:10.1056/NEJM199912163412503.
  7. Jouven X, Zureik M, Desnos M, Courbon D, Ducimetière P. Long-term outcome in asymptomatic men with exercise-induced premature ventricular depolarizations. N Engl J Med. 2000;343(12):826–833. doi:10.1056/NEJM200009213431201.
  8. Udall JA, Ellestad MH. Predictive implications of ventricular premature contractions associated with treadmill stress testing. Circulation. 1977;56(6):985–989.
  9. Preliminary report: effect of encainide and flecainide on mortality in a randomized trial of arrhythmia suppression after myocardial infarction. The Cardiac Arrhythmia Suppression Trial (CAST) Investigators. N Engl J Med. 1989;321(6):406–412. doi:10.1056/NEJM198908103210629.
  10. Goldstein S. Propranolol therapy in patients with acute myocardial infarction: the Beta-Blocker Heart Attack Trial. Circulation. 1983;67(6 Pt 2):I53–7.
  11. Moss AJ. MADIT-I and MADIT-II. J Cardiovasc Electrophysiol. 2003;14(9 Suppl):S96–8.
  12. Moss AJ, Hall WJ, Cannom DS, et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. Multicenter Automatic Defibrillator Implantation Trial Investigators. N Engl J Med. 1996;335(26):1933–1940. doi:10.1056/NEJM199612263352601.
  13. Buxton AE, Lee KL, Fisher JD, Josephson ME, Prystowsky EN, Hafley G. A randomized study of the prevention of sudden death in patients with coronary artery disease. Multicenter Unsustained Tachycardia Trial Investigators. N Engl J Med. 1999;341(25):1882–1890. doi:10.1056/NEJM199912163412503.
  14. Bardy GH, Lee KL, Mark DB, et al. Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005;352(3):225–237. doi:10.1056/NEJMoa043399.
  15. WikEM: Nonsustained Ventricular Tachycardia

Endocrine Emergencies

HPI

30 year-old female with a history of autoimmune polyglandular syndrome (adrenal, thyroid and endocrine pancreatic insufficiency), polysubstance use, brought to the emergency department by ambulance with reported chief complaint of fever. On presentation, the patient reported fever for one day, associated with cough. She was lethargic and confused, answering yes/no questions but unable to provide detailed history. She states that she has been taking her home medications as prescribed, which include hydrocortisone, fludrocortisone, synthroid and insulin. No collateral information was immediately available.

Additional history was obtained from chart review upon discharge. The patient was hospitalized two weeks prior with pneumonia and discharged after two days. For 2-3 days prior to presentation, she reported the following symptoms to family members: nausea/vomiting, cough, decreased oral intake, fevers, and palpitations – she did not take her home medications during this time.

Physical Exam

VS: T 38.6 HR 112 RR 18 BP 149/82 O2 90% RA
Gen: Alert, fatigued, slow responses.
HEENT: No meningeal irritation, dry mucous membranes.
Pulmonary: Tachypnea, inspiratory wheezing and faint crackles at left and right inferior lung fields, appreciated anteriorly as well.
Neuro: Alert, oriented to self, situation, not month/year. PERRL, EOMI, facial muscles symmetric, tongue protrudes midline without fasciculation. Peripheral sensation grossly intact to light touch and moves all extremities on command.

Labs

  • VBG: alkalemia, primary respiratory
  • CBC: no leukocytosis, normal differential, normocytic anemia
  • BMP: 131, 2.5 , 94, 28, 11, 1.6, 115
  • Mg: 1.3
  • Lactate: 1.0
  • TSH: 17 , T4: 1.03
  • Troponin: 0.129

ECG

ECG 1
ECG 2

Imaging

  • CXR: Negative acute.
  • CT Head: Negative acute.
  • CT Cardiac: NICM, EF 35%.
IM-0001-0026
IM-0001-0026
IM-0001-0030
IM-0001-0030
IM-0001-0034
IM-0001-0034
IM-0001-0038
IM-0001-0038
IM-0001-0042
IM-0001-0042
IM-0001-0046
IM-0001-0046
IM-0001-0050
IM-0001-0050
IM-0001-0054
IM-0001-0054
IM-0001-0058
IM-0001-0058
IM-0001-0062
IM-0001-0062
IM-0001-0066
IM-0001-0066
IM-0001-0070
IM-0001-0070

CT Chest non-contrast

  • Diffuse patchy GGO (pulmonary edema, atypical pneumonia, alveolar hemorrhage, others).
  • Multiple bilateral pulmonary nodules.
  • Possible pulmonary arterial hypertension.

Hospital Course

The patient’s evaluation in the emergency department was concerning for severe sepsis secondary to suspected pulmonary source (given association of fever with cough, hypoxia and abnormal chest imaging findings). The patient had persistent alteration in mental status concerning for CNS infection. While preparing for lumbar puncture, cardiac monitoring revealed sustained polymorphic ventricular tachycardia without appreciable pulse. CPR was initiated, amiodarone 150mg IV push administered and at first pulse check a perfusing sinus rhythm was noted with immediate recovery of prior baseline mental status. Amiodarone load was continued and additional potassium sulfate (PO and IV) was administered. Review of telemetry monitoring revealed preceding 30-45 minutes of non-sustained ventricular tachycardia. The patient had two more episodes of sustained ventricular tachycardia requiring defibrillation. The patient was admitted to the medical intensive care unit for continued management.

#Sustained Ventricular Tachycardia
Initially attributed to critical hypokalemia and hypomagnesemia. However, after appropriate repletion serial ECG’s continued to demonstrate prolonged QT interval (possibly acquired secondary to medications, later review revealed multiple promotility agents for treatment of gastroparesis which could contribute to QT-prolongation including erythromycin and metoclopramide, also associated with endocrinopathies). Early echocardiography demonstrated global hypokinesis with estimated EF 30-35%. This was initially attributed to severe sepsis, as well as recurrent defibrillation. However, cardiac CT after resolution of acute illness showed persistent depressed ejection fraction, no evidence of coronary atherosclerosis. The presence of non-ischemic cardiomyopathy (may be attributable to chronic endocrine dysfunction or prior history of methamphetamine abuse) associated with malignant dysrhythmias warranted ICD placement for secondary prevention which the patient was scheduled to receive.

#Severe Sepsis
Attributed to pulmonary source given CT findings, healthcare associated and covered broadly. Mental status gradually improved and returned to baseline. CT head was negative, lumbar puncture deferred.

#Hypokalemia
Unclear etiology. Adrenal insufficiency commonly associated with hyperkalemia and no history of surreptitious fludrocortisone use. Possibly secondary to GI losses. Improved with repletion.

#Autoimmune Polyglandular Syndrome
Started on stress-dose steroids in emergency department. Transiently developed DKA which was reversed appropriately and hydrocortisone was tapered to home regimen. Home levothyroxine was resumed.

Endocrine Emergencies: Hyperthyroidism

Symptoms

Constitutional Weight loss, heat intolerance, perspiration
Cardiopulmonary Palpitations, chest pain, dyspnea
Neuropsychiatric Tremor, anxiety, double vision, muscle weakness
Neck Fullness, dysphagia, dysphonia
Musculoskeletal Extremity swelling
Reproductive Irregular menses, decreased libido, gynecomastia

Signs

Vital signs Tachycardia, widened pulse pressure, fever
Cardiovascular Hyperdynamic precordium, CHF, atrial fibrillation, systolic flow murmur
Ophthalmologic Widened palpebral fissure, periorbital edema, proptosis, diplopia, restricted superior gaze
Neurologic Tremor, hyperreflexia, proximal muscle weakness
Dermatologic Palmar erythema, hyperpigmented plaques or non-pitting edema of tibia
Neck Enlarged or nodular thyroid

Thyroid Storm

Essentially an exaggeration of thyrotoxicosis featuring marked hyperthermia (104-106°F), tachycardia (HR > 140bpm), and altered mental status (agitation, delirium, coma).

Precipitants
Medical: Sepsis, MI, CVA, CHF, PE, visceral ischemia
Trauma: Surgery, blunt, penetrating
Endocrine: DKA, HHS, hypoglycemia
Drugs: Iodine, amiodarone, inhaled anesthetics
Pregnancy: post-partum, hyperemesis gravidarum

Scoring (Burch, Wartofsky)

Fever
99-100 5
100-101 10
101-102 15
102-103 20
103-104 25
>104 30
Tachycardia
90-110 5
110-120 10
120-130 15
130-140 20
>140 25
Mental Status
Normal 0
Mild agitation 10
Extreme lethargy 20
Coma, seizure 30
CHF
Absent 0
Mild (edema) 5
Moderate (rales, atrial fibrillation) 10
Pulmonary edema 15
GI
None 0
Nausea/vomiting, abdominal pain 10
Jaundice 20
Precipitating Event
None 0
Present 10
  • >45: thyroid storm
  • 25-44: impending thyroid storm
  • <25: unlikely thyroid storm

Management

Supportive measures
Volume resuscitation and cooling
Benzodiazepines for agitation
Beta-blockade
Propranolol 60-80mg PO q4h
Propranolol 0.5-1.0mg IV, repeat q15min then 1-2mg q3h
Esmolol continuous infusion
Endocrinology consultation
PTU, SSKI

Endocrine Emergencies: Hypothyroidism

Symptoms

Constitutional Weight gain, cold intolerance, fatigue
Cardiopulmonary Dyspnea, decreased exercise capacity
Neuropsychiatric Impaired concentration and attention
Musculoskeletal Extremity swelling
Gastrointestinal Constipation
Reproductive Irregular menses, erectile dysfunction, decreased libido
Integumentary Coarse hair, dry skin, alopecia, thin nails

Signs

Vital signs Bradycardia, hypothermia
Cardiovascular Prolonged QT, increased ventricular arrhythmia, accelerated CAD, diastolic heart failure, peripheral edema
Neurologic Lethargy, slowed speech, agitation, seizures, ataxia/dysmetria, mononeuropathy, delayed relaxation of reflexes
Musculoskeletal Proximal myopathy, pseudohypertrophy, polyarthralgia
Gastrointestinal Ileus

Myxedema Coma

Precipitants
Critical illness: sepsis (especially PNA), CVA, MI, CHF, trauma, burns
Endocrine: DKA, hypoglycemia
Drugs: amiodarone, lithium, phenytoin, rifampin, medication non-adherence
Environmental: cold exposure
Recognition
History: hypothyroidism, thyroidectomy scar and acute precipitating illness
Hypothermia: temp <95.9°F (or normal in presence of infection)
AMS: lethargy, confusion, coma, agitation, psychosis, seizures
Hypotension: refractory to volume resuscitation and pressors
Bradypnea: with hypercapnia and hypoxia
Hyponatremia

Management

  • Airway protection
  • Fluid resuscitation
  • Thyroid hormone replacement
    • Young, otherwise healthy patients: T3 10ug IV q4h
    • Elderly, cardiac compromise: 300ug IV x1
  • Hydrocortisone: 50-100mg IV q6-8h
  • Treat precipitating illness

Interpretation of Thyroid Function Tests

Condition TSH T4
None Normal Normal
Hyperthyroidism Low High
Hypothyroidism High Low
Subclinical hyperthyroidism Low Normal
Subclinical hypothyroidism High Normal
Sick euthyroid Low Low

Endocrine Emergencies: Adrenal Insufficiency

Either primary due to adrenal gland failure (often secondary to autoimmune destruction), or secondary most often due to exogenous glucocorticoid administration (usually requiring more than 30mg/day for > 3wks).

Symptoms

Constitutional Weakness, fatigue
Gastrointestinal Anorexia, nausea, cramping
Neuropsychiatric Depression, apathy
Reproductive Amenorrhea, decreased libido
Musculoskeletal Myalgia, arthralgia

Signs

General Hyponatremia, orthostatic hypotension, low-grade fever
Primary Hyperpigmentation, hyperkalemia, hyperchloremia, acidosis
Secondary Hypoglycemia

Management

Maintenance
Hydrocortisone 20mg qAM, 10mg qPM
Fludrocortisone 50-100ug daily
Minor illness (x2)
Hydrocortisone 40mg qAM, 20mg qPM
Fludrocortisone 50-200ug daily
Adrenal Crisis
Dexamethasone 4mg IV or hydrocortisone 100mg IV
2-3L 0.9% NaCl
Treat precipitating illness

Life-Threatening Electrolyte Abnormalities3

Critical Hypokalemia

Causes
GI losses (diarrhea, laxative use)
Renal losses (hyperaldosteronism, diuretics)
Cellular shifts (alkalosis)
ECG changes
U-waves 4
T-wave flattening
Ventricular arrhythmias (exacerbated with digoxin use)
Treatment
Maximum rate 10-20mEq/h with ECG monitoring
If malignant ventricular arrhythmias or arrest imminent, consider more rapid administration (10mEq over 5 minutes)

 

Critical Hypomagnesemia

Causes
GI, renal losses
Thyroid dysfunction
Treatment
1-2g IV over 5-60 minutes or IVP for Torsades

Conclusion

Unfortunately, this patient’s comprehensive clinical picture does not fit neatly into a particular category of endocrinologic pathology. Her underlying autoimmune disorder manifests both primary adrenal and thyroid dysfunction. Components of the patient’s presentation are suggestive of critical hypothyroidism (myxedema coma) including alteration in mental status, QT-prolongation and hyponatremia as well as possible precipitant of pneumonia. However, despite elevated TSH, the patient’s free T4 level was within normal range. Also absent was hypoventilation (the patient was appropriately tachypneic for degree of hypoxia and with resultant respiratory alkalosis) or bradycardia/hypothermia.
Similarly, adrenal insufficiency is typically associated with hyperkalemia, whereas our patient had critical hypokalemia that was determined to be at least a contributory factor to her ventricular dysrhythmia. The etiology of the patient’s hypokalemia remained unexplained.

References:

  1. Sharma, A., & Levy, D. (2009). Thyroid and Adrenal Disorders. In Rosen’s Emergency Medicine (8th ed., Vol. 2, pp. 1676-1692). Elsevier Health Sciences.
  2. Savage MW, Mah PM, Weetman AP, Newell-Price J. Endocrine emergencies. Postgrad Med J. 2004;80(947):506–515. doi:10.1136/pgmj.2003.013474.
  3. ECC Committee, Subcommittees and Task Forces of the American Heart Association. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2005;112(24 Suppl):IV1–203. doi:10.1161/CIRCULATIONAHA.105.166550.
  4. Levis JT. ECG diagnosis: hypokalemia. Perm J. 2012;16(2):57.