Dr. Zack Dale recently presented a case of a 64 -year-old woman seen in EP clinic for palpitations, ultimately found to have atrial fibrillation in the setting of T3 thyrotoxicosis.

Palpitations: Differential Diagnosis

Cardiac: Arrhythmias, valvular disease, cardiomyopathy

Metabolic Disorders: Hypoglycemia, Thyrotoxicosis

Medications/Substances: Sympathomimetics, Anticholingerics, Beta-Blocker Withdrawal, Cocaine, Amphetamines, Caffeine, Nicotine

Psychiatric Disorders: Panic Disorder, General Anxiety Disorder, Depression. Dr. Bains cautioned residents to be wary of gender biases associated with such non-specific complaints and the tendency to disproportionately attribute them to a psychiatric etiology when encountered in women.

Catecholamine Excess: Exercise, Stress


Physical exam, particularly cardiac exam to assess for rate/rhythm and valvular pathology. This patient’s exam was notable for irregularly irregular tachycardia. An irregularly irregular rhythm is associated with one of 3 arrhythmias: atrial fibrillation, atrial flutter with variable block or multi-focal atrial tachycardia, which can be differentiated based on 12-Lead ECG. This patient’s ECG showed absence of regular repeating P waves and irregular R-R intervals, and thus was consistent with a diagnosis of atrial fibrillation.


Management of new onset-atrial fibrillation

1. Patients with a new diagnosis of atrial fibrillation should be evaluated for urgent needs (hemodynamic instability, evidence of organ hypoperfusion, signs of active ischemia, heart failure, and other pathology (ie COPD exacerbation, sepsis). The stable patient (even if tachycardic) can be managed in the outpatient setting assuming reasonable follow-up can be ascertained.

2. The patient with a new diagnosis of atrial fibrillation should be evaluated for potential “reversible” causes and risk factors

•Binge drinking

•Illicit drugs/sympathomimetic drugs

•Surgery (particularly cardiothoracic surgery)




•Pulmonary disease (COPD, PNA, PE, etc)


•Structural heart disease (valvular disease, Wolff-Parkinson-White syndrome,etc)

•Other atrial arrhythmias

Treatment of these should be a priority

3. Initial management of atrial fibrillation involves rate control and risk-based anticoagulation.