Applied Evidence

Is an underlying cardiac condition causing your patient’s palpitations?

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References

Lab work. A comprehensive metabolic panel, complete blood count, lipid panel, and thyroid panel should be ordered for all patients with palpitations. Possible additional tests include a urine drug screen (when recreational drug use is suspected); cardiac enzymes; N-terminal-pro hormone B-type natriuretic peptide (when there is evidence of CAD or heart failure); and urinary catecholamines (when pheochromocytoma is suspected).

Other investigations. Echocardiography is indicated when structural heart disease is suspected (TABLE 12-4). Patients who have multiple risk factors for CAD or exertional symptoms might warrant a stress test.

Management

PACs and PVCs

Typically, patients are counseled to minimize potential adrenergic precipitants, such as smoking, alcohol, stress, and caffeine. However, limited studies have demonstrated no significant arrhythmogenic potential of a modest dose of caffeine (200 mg), even in patients with known life-threatening ventricular arrhythmias.16 Beta-blockers and nondihydropyridine calcium channel blockers (CCBs) can reduce the severity of symptoms related to premature ectopic beats and might reduce their frequency, although response is inconsistent. Use of these medications for PACs is largely based on expert opinion and extrapolated from use in other supraventricular and ventricular arrhythmias.

Implantable cardioverter defibrillator therapy is indicated in patients with nonsustained VT due to prior myocardial infarction, left ventricular ejection fraction ≤ 40%, and inducible ventricular fibrillation or sustained VT on electrophysiological study.7

Patients with a high burden of ectopy who do not respond to treatment with AV nodal-blocking agents should be referred to Cardiology for other antiarrhythmic agents or catheter ablation. Last, asymptomatic ectopy does not need to be treated; there is no clear evidence that suppression with pharmacotherapy improves overall survival.15,17

Supraventricular tachycardia

The priority when evaluating any tachycardia is to assess the patient’s stability. Unstable patients should be treated immediately, usually with cardioversion, before an extensive diagnostic evaluation.18 Patients with wide-complex tachycardia (QRS > 120 ms) are generally more unstable and require more urgent therapy and cardiac consultation or referral. Hemodynamically stable patients with narrow-complex SVT (QRS < 120 ms) can be treated with IV adenosine, which has an 89.7% success rate.18,19 If adenosine is unsuccessful, cardioversion is indicated.

Stable patients with minimal symptoms and short episodes do not need treatment.

Continue to: Vagal maneuvers

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