Controversies in cardiovascular medicine. Hypertrophic obstructive cardiomyopathy: alcohol septal ablation
Michael A Fifer1, Ulrich Sigwart
1Cardiology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
Insights
Alcohol septal ablation (ASA) effectively treats hypertrophic obstructive cardiomyopathy by reducing the left ventricular outflow tract gradient. This minimally invasive procedure offers clinical success with comparable mortality to septal myectomy.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiac Surgery
Background:
- Alcohol septal ablation (ASA) emerged in 1994 as an alternative to surgical septal myectomy.
- It targets symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) unresponsive to medical management.
- ASA aims to alleviate symptoms by inducing a controlled infarction in the interventricular septum.
Purpose of the Study:
- To evaluate the efficacy and safety of Alcohol Septal Ablation (ASA) for Hypertrophic Obstructive Cardiomyopathy (HOCM).
- To assess the impact of ASA on left ventricular outflow tract (LVOT) obstruction and patient symptoms.
- To compare ASA outcomes with traditional septal myectomy.
Main Methods:
- ASA involves targeted injection of alcohol into the basal interventricular septum to induce infarction.
- Myocardial contrast echocardiography is utilized to guide alcohol dosage and minimize infarct size.
- Non-randomized comparisons were made between ASA and septal myectomy.
Main Results:
- ASA successfully reduces the LVOT gradient and improves symptoms in most patients.
- The procedure leads to an increased LVOT diameter and regression of pressure-overload-induced hypertrophy.
- Complete heart block is the primary morbidity, potentially requiring pacemaker implantation.
Conclusions:
- ASA is a highly effective treatment for symptomatic HOCM with LVOT obstruction.
- Improvements in technique, such as using myocardial contrast echocardiography, have reduced complications.
- ASA demonstrates comparable mortality and functional outcomes to septal myectomy.
Abstract:
Alcohol septal ablation (ASA) was introduced in 1994 as an alternative to septal myectomy for patients with hypertrophic obstructive cardiomyopathy and symptoms refractory to medical therapy. This procedure alleviates symptoms by producing a targeted, limited infarction of the upper interventricular septum, resulting in an increase in left ventricular outflow tract (LVOT) diameter, a decrease in LVOT gradient, and regression of the component of LV hypertrophy that is due to pressure overload. Clinical success, with improvement in symptoms and reduction in gradient, is achieved in the great majority of patients with either resting or provocable LVOT obstruction. The principal morbidity of the procedure is complete heart block, resulting in some patients in the requirement for a permanent pacemaker. The introduction of myocardial contrast echocardiography as a component of the ASA procedure has contributed to the induction of smaller myocardial infarctions with lower dosages of alcohol and, in turn, fewer complications. Non-randomized comparisons of septal ablation and septal myectomy have shown similar mortality rates and post-procedure New York Heart Association class for the two procedures.
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