• Inflammatory Disease Guidelines

New practice guidelines for hypertrophic cardiomyopathy (HCM) were issued in 2011 by the American College of Cardiology Foundation/American Heart Association (ACCF/AHA) [Gersh BJ et al. Circulation 2011].

Michael J Ackerman, MD, Mayo Clinic, Rochester, Minnesota, USA, discussed the new guidelines for genetic testing for HCM from both the ACCF/AHA and from the Heart Rhythm Society/European Heart Rhythm Association (HRS/EHRA) [Ackerman MJ et al. Heart Rhythm 2011.

Under the ACCF/AHA guidelines genetic testing:

• is recommended in patients with atypical clinical presentation of HCM or when another genetic condition is suspected (Class I; Level of Evidence [LoE] B)

• is reasonable in the index patient to facilitate identification of first-degree family members who are at risk for developing HCM (Class IIa; LoE B)

Using the HRS/EHRA guidelines (both Class I; LoE C [ie Expert Consensus]):

• comprehensive or targeted HCM genetic testing is recommended for any patient in whom a cardiologist has established a clinical diagnosis of HCM based on examination of the patient's clinical history, family history, and electro-/echocardiographic phenotype

• mutation–specific genetic testing is recommended for family members and appropriate relatives following the identification of the HCM–causative mutation in an index case

Milind Y. Desai, MD, Cleveland Clinic, Cleveland, Ohio, USA, presented a summary of the recommendations for the use of echocardiography. Some of the specific recommendations concerned the use of transthoracic echo as part of:

• the initial evaluation of all patients with suspected HCM (Class I; LoE B)

• the screening algorithm for family members (Class I; LoE B)

• periodic screening for children of HCM patients (Class I; LoE C)

Martin S. Maron, MD, Tufts Medical Center, Boston, Massachusetts, USA, presented the recommendations for the use of cardiac MRI (CMR). The new guidelines indicate the use of CMR imaging:

• in patients with suspected HCM to detect segmental areas of increased left ventricular wall thickening that are not seen by echocardiography (eg, anterolateral wall, apex and posterior septum; Class I; LoE B)

• in patients with HCM when this additional information might have an impact on risk assessment and treatment decisions regarding appropriate selection of invasive septal reduction therapy (Class I; LoE B)

• for identification of high–risk patients using late gadolinium enhancement in selected HCM patients in whom risk stratification remains uncertain after assessment with conventional sudden death markers (Class IIb; LoE C)

Perry M. Elliott, MD, The Heart Hospital, University College London, London, United Kingdom, presented some of the new recommendations concerning the symptoms in HCM, such as chest pain, dyspnea and arrhythmia that may be explained by decreased myocardial perfusion and the resultant myocardial ischemia:

• assessment of coronary anatomy with computed tomographic angiography is reasonable for HCM patients with chest discomfort and a low likelihood of coronary artery disease (CAD) to assess for possible concomitant CAD (Class IIa; LoE C)

• the assessment of ischemia or perfusion abnormalities suggestive of CAD with single–photon emission computed tomography (SPECT) or positron emission tomography (PET) myocardial perfusion imaging (MPI) is reasonable in patients with HCM with chest discomfort and a low likelihood of CAD to rule out possible concomitant CAD (Class IIa; LoE C)

• recommendations do not support the use of routine SPECT MPI or stress echocardiography for detection of “silent” CAD–related ischemia in patients with HCM who are asymptomatic; nor is the use of PET to detect the presence of microvascular ischemia recommended for the prognosis of HCM (Class III; LoE C)

Overall there is a low annual rate of mortality from sudden cardiac arrest due to HCM. However, unacceptable death rates in the HCM population remain even in those being treated with medications, explained Matthew W. Martinez, MD, Lehigh Valley Health Network, Allentown, Pennsylvania, USA. Implantable cardioverter–defibrillators (ICDs) are a useful treatment option in patients who are at high risk of SCD, defined as young patients with a positive family history of SCD, unexplained syncope, left ventricularwall thickness >30 mm, associated CAD, nonsustained ventricular tachycardia, exercised–induced hypotension, or fibrosis detected by MRI (Class Ib; LoE B).

Paul Sorajja, MD, Mayo Clinic, Rochester, Minnesota, USA, comparing the outcomes from myectomy and septal ablation, reported that myectomy is the recommended standard treatment for HCM (Class IIa; LoE C), as it offers low immediate post–operative risk, a >95% chance of symptom relief and superb long–term survival benefits. Septal ablation works well if patients are carefully selected (Class IIa or IIb; LoE B) but has higher acute complications, often including heart block, hence the need for a pacemaker following ablation. The two procedures appear to be comparable in terms of gradient relief, symptom relief, and early survival; however, there continues to be concern regarding the potential long–term consequences of the ablation–induced infarction, including data from ICD monitoring that suggest an increased risk of ventricular arrhythmia among HCM patients post ablation compared with septal myectomy. A definitive randomized trial that compared long–term outcomes between these two procedures has yet to be performed.

• © 2012 MD Conference Express®