Management of Palpitations with Minimal ST Elevation

Patient Assessment and Treatment Failure

The patient's worsening symptoms on metoprolol XR 100 mg BID indicate treatment failure or possible adverse effect, suggesting the need for alternative rate control strategies 1
The presence of ST elevation in inferior leads may indicate possible inferior wall ischemia or injury, and risk of developing bradycardia or heart block with continued beta-blocker use, according to the American College of Cardiology 2

For patients with atrial fibrillation or other supraventricular tachycardia, the American Heart Association recommends initiating diltiazem for rate control, with an initial IV dose of 0.25 mg/kg (typically 15-20 mg) over 2 minutes, and a maintenance infusion of 5-15 mg/hour 3
Calcium channel blocker therapy, preferably diltiazem or verapamil, is recommended for continued rate control in patients with confirmed atrial fibrillation/flutter with ST changes, as per the American College of Cardiology guidelines 5
The American College of Cardiology advises against using beta-blockers in patients with risk factors for cardiogenic shock, such as those with STEMI 1

Diltiazem is contraindicated in patients with decompensated heart failure, pre-excited atrial fibrillation, and severe hypotension, as stated by the American Heart Association 3
The American College of Cardiology recommends avoiding calcium channel blockers in patients with certain conditions, and instead considering alternative treatments, such as amiodarone for rhythm control in patients with underlying structural heart disease 5

A 12-lead ECG should be obtained to evaluate the ST elevation and assess for arrhythmias, and cardiac biomarkers should be checked to evaluate for myocardial injury
Echocardiography is recommended to assess wall motion abnormalities corresponding to ST changes, evaluate for structural heart disease, and rule out other causes of palpitations, as per standard medical practice 5