[Interventional treatment in hypertrophic cardiomyopathy]

Abstract

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease phenotypically expressed in the general population at about 0.2%. Annual mortality rate is about 1% in unselected patients, 3-6% in patients with severe symptoms, and 17% following resuscitation from ventricular tachycardia (VT)/ventricular fibrillation (VF). 50-80% of deaths are sudden. Beneath effective treatment in severe symptoms of heart failure (most common in midlife and beyond) the prevention of sudden death (most common in young patients) continues to be a major challenge. The highest risk has been associated with any of the following markers: 1. prior cardiac arrest or spontaneous sustained VTs, 2. a family history of premature HCM-related death, 3. extreme left ventricular hypertrophy (> or = 30 mm), 4. syncope, 5. multiple bursts of nonsustained VTs, 6. hypotensive blood pressure response to exercise, and 7. marked septal scarring (hyperenhancement in magnetic resonance imaging). Treatment options in patients with drug-refractory symptoms or increased risk of sudden death are surgical myectomy, transcoronary ablation of septal hypertrophy (TASH), dual-chamber pacing, ablation of atrial fibrillation (or the AV node), and the implantable cardioverter defibrillator (ICD). 1. Surgical myectomy effectively improves symptoms, hemodynamics and probably prognosis. Long-term results are well known, but patients' preference and the number of experienced surgical centers are fading. Randomized studies are missing. 2. TASH induces quite similar improvements in symptoms and hemodynamics. It is remarkably evaluated for a postprocedural follow-up of up to 10 years, and it is the preferred mode of treatment in patients. However, information on long-term prognosis, rhythmogenic effects and randomized studies are missing. For the prevention of sudden death, TASH has to be combined with an ICD. 3. Dual-chamber pacing was evaluated in randomized crossover studies, but symptomatic and hemodynamic improvements and patients' preference are substantially lower than for TASH. 4. The ICD has the potential to alter prognosis in secondary (class I indication) and primary prevention. HCM patients should undergo a risk stratification assessment. Prophylactic implants base on a clinical profile with two or more risk markers (sometimes one risk marker). 5. Ablation of atrial fibrillation or the AV node is indicated to improve symptoms in patients with fast ventricular rates despite medical treatment. For the prevention of sudden death, it has to be combined with an ICD.