[Therapeutic approaches in symptomatic hypertrophic obstructive cardiomyopathy]

Hypertrophic cardiomyopathy is a complex and heterogeneous disease. Although most patients experience just a few symptoms, and have a good prognosis, there are others whose symptoms are severe and progressive, determined by different pathophysiological elements such as diastolic dysfunction, myocardial ischemia, arrhythmias and subaortic obstruction. Approximately 20-30% of hypertrophic cardiomyopathy patients develop an intraventricular dynamic gradient, which in some cases, is responsible for severe symptoms which are ameliorated once the obstruction is reduced. In many cases the symptoms can be controlled with medical treatment which includes betablockers, calcium-channel antagonists and dysopiramide, but some patients will still experience severe and refractory symptoms. This subgroup of patients, which represent approximately 5-10% of patients with hypertrophic cardiomyopathy, can be problematic from a management perspective. For many years, septal myectomy and/or mitral valve replacement offered the only effective alternative therapy for these patients. However, the high rates of morbidity and mortality associated with these procedures have necessitated the search for new and less invasive procedures such as ventricular pacing and percutaneous septal ablation. Although the initial results with sequential pacing were encouraging, further studies have suggested a significant placebo effect, which makes its application controversial. In the last 5 years selective embolization of the septal artery precipitating a localized myocardial infarction has been utilized to reduce the subaortic gradient. The potential indications and efficacy of these new forms of treatment, like ventricular pacing and percutaneous septal ablation, are presently under evaluation and are the main subject of this review. Medical treatment, with either beta-blockers, calcium channel antagonists or dysopiramide constitutes the first therapeutic step. Surgery, while alleviating the subaortic obstruction and reducing the intraventicular pressure and mitral insufficiency, produces important and long-lasting symptomatic and functional improvement in most of these patients, and it continues to be an important therapeutic alternative in these cases. If the first results with sequential pacemaker implants were encouraging, today it is alluded to an important placebo effect that causes its application to be controversial. In the last 5 years the path has been made in the creation of a septal infarction located through the embolization of the septal branches to reduce the gradient.