From the Guidelines
Digoxin is the least useful medication in the treatment of Hypertrophic Cardiomyopathy (HCM). Unlike the other medications listed, digoxin does not address the fundamental pathophysiology of HCM and may actually worsen symptoms. Digoxin increases cardiac contractility, which can exacerbate left ventricular outflow tract obstruction in HCM patients, potentially worsening their condition 1. In contrast, verapamil (a calcium channel blocker), disopyramide (an antiarrhythmic), and beta blockers are all considered effective treatments for HCM. These medications work by reducing contractility, heart rate, and outflow obstruction, thereby improving symptoms and hemodynamics in HCM patients.
Key Points to Consider
- Beta blockers and verapamil are typically first-line treatments that reduce myocardial oxygen demand and improve diastolic filling, while disopyramide can be added for patients with significant outflow tract obstruction who remain symptomatic 1.
- The 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy recommends discontinuation of vasodilators or digoxin in patients with obstructive HCM because these agents can worsen symptoms caused by dynamic outflow tract obstruction 1.
- Verapamil is potentially harmful in patients with obstructive HCM and severe dyspnea at rest, hypotension, very high resting gradients, as well as all children <6 weeks of age 1.
Clinical Implications
- Digoxin should generally be avoided in HCM unless there are specific comorbid conditions like atrial fibrillation with rapid ventricular response that cannot be controlled by other means.
- The use of digoxin in HCM patients may lead to increased morbidity and mortality due to its potential to worsen symptoms and exacerbate left ventricular outflow tract obstruction.
- Clinicians should prioritize the use of beta blockers, verapamil, and disopyramide in the treatment of HCM, as these medications have been shown to improve symptoms and hemodynamics in HCM patients 1.
From the Research
Medication Options for Hypertrophic Cardiomyopathy (HCM)
The following medications are considered for the treatment of HCM: Verapamil, Digoxin, Disopyramide, and Beta blockers.
Least Useful Medication
- Digoxin is not mentioned in the provided studies as a recommended treatment for HCM, suggesting it may be the least useful medication for this condition 2, 3, 4, 5, 6.
- Verapamil has limited utility in obstructive HCM with high resting gradients due to its vasodilating effects, which can worsen gradient and symptoms 2, 3.
- Disopyramide is indicated for patients with obstruction who do not respond to beta blockers and/or verapamil, and has been shown to decrease resting gradients and offer meaningful relief of symptoms 2, 3.
- Beta blockers are the first-line treatment for HCM, and are effective in decreasing the rise in gradient that accompanies exercise 2, 3, 4, 5, 6.
Comparison of Medications
- A head-to-head comparison of intravenous drug administration in individual obstructive HCM patients showed the relative efficacy for lowering gradient was disopyramide > beta-blockade > verapamil 2.
- A study comparing beta blockers and verapamil found no significant differences in cardiovascular death, hospitalization for heart failure, and hospitalization for atrial fibrillation between the two groups 4.