Beta Adrenergic Blocking Agent used to treat cardiac arrhythmias and hypertrophic cardiomyopathy.

• A. Timolol
• B. Atenolol
• C. Propranolol
• D. Metoprolol

Answer: (C)

Lowering sympathetic stimulation to the heart helps both control arrhythmias and lessen the dynamic obstruction seen in hypertrophic cardiomyopathy. A beta-adrenergic blocker does this by reducing heart rate and myocardial contractility, which decreases the likelihood of tachyarrhythmias and, in hypertrophic cardiomyopathy, reduces the left-ventricular outflow tract gradient that worsens with more vigorous contraction.

Propranolol is a non-selective beta-blocker, meaning it blocks both beta-1 receptors in the heart and beta-2 receptors elsewhere in the body. This broad blockade provides strong antiarrhythmic effects and a more pronounced reduction in contractility, which helps relieve the dynamic obstruction characteristic of hypertrophic cardiomyopathy. Among the listed drugs, propranolol is the classic choice for addressing both arrhythmias and hypertrophic cardiomyopathy because of its non-selective action and robust overall sympathetic inhibition.

Timolol is primarily used topically for glaucoma, with limited systemic antiarrhythmic utility. Atenolol and metoprolol are beta-1–selective blockers; they can treat arrhythmias and provide some benefit in hypertrophic cardiomyopathy, but they don’t offer the same broad receptor blockade as propranolol, which is why propranolol is the preferred option in this combined context.