From the Guidelines
Beta blockers are the first-line treatment for hypertrophic cardiomyopathy (HCM) and work by slowing heart rate and reducing the force of heart contractions, thereby minimizing symptoms like chest pain, shortness of breath, palpitations, and lightheadedness. According to the most recent guidelines 1, beta blockers are generally considered the first-line agent for most patients with obstructive HCM. The mechanism of action involves blocking beta-adrenergic receptors, preventing adrenaline and noradrenaline from increasing heart rate and contractility.
Key Points to Consider
- Beta blockers decrease the heart's oxygen demand and improve diastolic filling time, reducing left ventricular outflow tract obstruction 1
- Medications like metoprolol, atenolol, or propranolol are commonly used, with dosing starting low and increasing gradually under medical supervision 1
- Potential side effects include fatigue, dizziness, and bronchospasm, and beta blockers should be used cautiously in patients with asthma, diabetes, or certain heart conduction disorders 1
- The latest guidelines from 2024 1 emphasize the importance of beta blockers in managing symptomatic, obstructive HCM, and recommend titrating medications to a dose where symptom benefit is observed.
Clinical Considerations
- Beta blockers should not be declared as failed until demonstrated physiologic evidence of beta-blockade (ie, suppression of resting heart rate) is reported 1
- Calcium channel blockers, such as verapamil or diltiazem, are reasonable alternatives to beta-blocker therapy, but their use in combination with beta blockers is not supported by evidence 1
- Eliminating medications that may promote outflow tract obstruction, such as pure vasodilators and high-dose diuretics, is also crucial in managing symptomatic, obstructive HCM 1
From the Research
Beta Blockers in HOCM
- Beta blockers are used to treat symptoms in patients with hypertrophic obstructive cardiomyopathy (HOCM) 2, 3.
- They are negative inotropic drugs, which means they decrease the contractility of the heart muscle, reducing the obstruction in the left ventricular outflow tract (LVOT) 2.
- Beta blockers are often the first-line treatment for symptomatic patients with HOCM, especially those with no gradient or with a gradient that appears only on exertion 3.
- They can help control symptoms such as chest pain, shortness of breath, and fainting spells, and can also help prevent sudden cardiac death 2, 4.
Combination Therapy
- In some cases, beta blockers may be used in combination with other medications, such as disopyramide or verapamil, to control symptoms and reduce the LVOT gradient 2, 4.
- Disopyramide is often added to beta blockers in patients who do not respond to beta blockers alone, and can help reduce the LVOT gradient and improve symptoms 4.
- Verapamil, a non-dihydropyridine calcium channel blocker, may be used in patients who cannot tolerate beta blockers or who have non-cardiac side effects from beta blockers 2.
Patient Selection
- The use of beta blockers in HOCM should be individualized, taking into account the patient's symptoms, LVOT gradient, and other medical conditions 5.
- Patients with HOCM should be closely monitored while on beta blockers, with regular follow-up appointments and echocardiograms to assess the effectiveness of treatment and adjust the dosage as needed 2, 4.