With nearly 600,000 people affected by hypertrophic cardiomyopathy (HCM), a disease that goes largely undetected and can decrease life expectancy, the American Heart Association (AHA) and American College of Cardiology Foundation (ACCF) put forth new guidelines about recommendations on how to detect, treat and manage patients with the genetic disease.
The guidelines, published online Nov. 8 in Circulation, outline the prevalence of the disease, the varying diagnoses and proper management strategies for HCM. Additionally, the committee’s aim was to clear up controversies that surround clinical management strategies including genetic testing and other treatments including septal reduction therapy (septal myectomy and alchohol septal ablation). The authors said that controversy has also stemmed from which HCM patients should be placed with an implantable cardioverter defibrillator (ICD).
The writing committee called putting forth new treatment and management strategies difficult because little evidence regarding HCM in clinical trials is available.
However, the task force recommended the following for Class I HCM patients:
- Genetic testing: Evaluating familial inheritance and genetic counseling is recommended as part of the assessment for patients with HCM. Additionally, screening is recommended in first-degree relatives of patients with HCM.
- Electrophysiology: A 12-lead ECG is recommended in the initial evaluation of patients with HCM. Additionally, 24-hour Holter monitoring is recommended in the initial evaluation of patients with HCM to detect ventricular tachycardia (VT) and identify patients who could be candidates for an ICD. The task force also recommended a repeat ECG for patients with HCM when symptoms worsen.
- Stress Testing: Treadmill exercise testing may be a reasonable strategy to determine HCM patients’ functional capacity and response to therapy. Additionally, a treadmill test with ECG and blood pressure monitoring is a reasonable approach for sudden cardiac death prediction in these patients.
- Cardiac MRI: Imaging is indicated in patients with suspected HCM when an echocardiography exam is inconclusive for diagnosis. Additionally, CMR imaging is indicated in patients with known HCM when additional information that may have had an impact on management or decision making regarding invasive management is not clearly defined.
On top of the aforementioned recommendations for HCM patients, the task force recommended beta-blocker drugs be used for the treatment of symptoms in HCM patients; however, they noted that caution should be applied in patients with sinus bradycardia or severe conduction disease.
For Class I patients, septal reduction therapy was recommended, but only when performed by experienced operators. However, the procedure should not be conducted in adult patients with HCM who are asymptomatic with normal exercise tolerance or whose symptoms are controlled by optimal medical therapy, the task force noted.
“The decision to place an ICD in patients with HCM should include application of individual clinical judgment, as well as a thorough discussion of the strength of evidence, benefits, and risks to allow the informed patient’s active participation in decision making."
Additionally, the task force recommended ICD placement for patients with HCM who also have documented cardiac arrest, ventricular fibrillation or hemodynamically VT. However, the task force wrote that nearly 25 percent of patients with HCM experience complications with ICD. These complications often include lead complications, device-related infection and bleeding or thrombosis complications.
“Although much progress has been made in understanding HCM, more research is needed to present more opportunities to improve patient outcomes,” the task force concluded.