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.