Is atenolol (beta-blocker) a suitable treatment option for an adult patient with palpitations and no significant medical history, such as asthma, diabetes, or peripheral artery disease?

Atenolol for Palpitations

Beta-blockers, including atenolol, are effective for treating palpitations in adults without contraindications, but metoprolol or bisoprolol are preferred over atenolol due to superior cardiovascular outcomes and more favorable pharmacologic profiles. 1, 2

Why Beta-Blockers Work for Palpitations

Beta-blockers competitively inhibit catecholamine effects on cardiac beta-1 receptors, reducing heart rate, contractility, and the sensation of palpitations by blocking the sympathetic nervous system's "fight or flight" response. 3 This mechanism makes them particularly effective for:

• Hyperkinetic circulation states (palpitations with tachycardia, anxiety, and heightened sympathetic tone) 4, 5
• Focal atrial tachycardia, where IV beta-blockers terminate or slow the arrhythmia in 30-50% of patients 6
• Supraventricular arrhythmias, including prevention of recurrence once control is achieved 7
• Mitral valve prolapse with palpitations, where beta-blockers are the treatment of choice 1

Why Atenolol Is Not First-Line

The American College of Cardiology explicitly states that atenolol should not be used as first-line therapy because it is less effective than placebo in reducing cardiovascular events. 2 This critical limitation stems from:

• Inferior cardiovascular protection compared to other beta-blockers like carvedilol, metoprolol succinate, and bisoprolol 2
• Once-daily dosing that may not provide consistent 24-hour beta-blockade for symptomatic control 7, 8
• Renal elimination requiring dose adjustment in moderate-to-severe renal impairment (GFR <30 mL/min) 8

Preferred Beta-Blockers for Palpitations

For acute symptomatic palpitations, the European Society of Cardiology recommends metoprolol 2.5-10 mg IV bolus over 2 minutes, repeated as needed, or esmolol for ultra-short acting control. 1

For chronic management, preferred options include:

• Metoprolol 25-100 mg BID (immediate release) or 50-400 mg daily (extended release) 1
• Bisoprolol, carvedilol, or nebivolol with specific dosing per ESC guidelines 1
• Beta-1 selective agents (metoprolol, bisoprolol) are safer than non-selective agents (carvedilol) in patients with mild bronchospasm 1

When Atenolol May Be Acceptable

Despite not being first-line, atenolol can be used for palpitations when:

• Other beta-blockers are unavailable or not tolerated 7
• CNS side effects are problematic with lipophilic beta-blockers like propranolol, since atenolol's low lipid solubility results in fewer nightmares, hallucinations, insomnia, and depression 8, 9
• Dosing simplicity is paramount, as atenolol has a narrow dose-response range (50-100 mg once daily) that obviates highly individualized titration 7, 8

Critical Contraindications to Screen For

Absolute contraindications to beta-blockers (including atenolol) in patients with palpitations: 1, 2

• Decompensated heart failure
• Pre-excited atrial fibrillation/flutter (Wolff-Parkinson-White syndrome)
• AV block greater than first degree
• Severe sinus node dysfunction
• Severe bronchospasm or active asthma exacerbation
• Hemodynamic instability or cardiogenic shock

Relative cautions:

• Diabetes mellitus (beta-blockers mask hypoglycemia symptoms, particularly tachycardia) 1, 3
• Peripheral artery disease (though beta-1 selective agents are generally safe) 6
• COPD (beta-1 selective agents like atenolol are acceptable, contrary to older teaching) 6

Monitoring Requirements

When initiating beta-blocker therapy for palpitations: 1

• Assess heart rate control both at rest and during activity
• Monitor for hypotension and bradycardia, especially during IV administration
• Watch for heart failure exacerbation (peripheral edema, dyspnea, orthopnea)
• Avoid excessive bradycardia when treating paroxysmal tachycardia, as this creates risk for bradyarrhythmias between episodes
• Target heart rate should generally remain above 60 bpm in elderly patients to avoid serious adverse cardiovascular events 6

Common Pitfalls to Avoid

• Do not use beta-blockers in vasospastic angina or cocaine/methamphetamine intoxication, as unopposed alpha-receptor stimulation can worsen coronary vasospasm 3
• Do not combine with verapamil or diltiazem in patients with reduced ejection fraction (LVEF <40%), as negative inotropic effects compound 1
• Do not abruptly discontinue beta-blockers, as this can precipitate rebound tachycardia and hypertension
• Recognize that atenolol requires dose reduction in renal impairment, unlike metoprolol which is hepatically metabolized 8

Practical Algorithm for Beta-Blocker Selection

1. Screen for absolute contraindications (decompensated HF, AV block, severe asthma, pre-excitation syndromes) 1, 2
2. Choose metoprolol or bisoprolol as first-line for palpitations unless specific contraindications exist 1, 2
3. Consider atenolol only if CNS side effects limit other beta-blockers or cost/availability is prohibitive 8, 9
4. Start low, go slow: Metoprolol 25 mg BID or atenolol 50 mg daily, titrating based on symptom control and heart rate response 1, 7
5. Reassess at 2-4 weeks for efficacy, tolerability, and need for dose adjustment or alternative therapy 1