Vector electrocardiographic alterations after percutaneous septal ablation in obstructive hypertrophic cardiomyopathy: possible anatomic causes

Abstract

Objective -Analyze the dromotropic disturbances (vector-electrocardiographic) The appearance of decreasing exercise capacity in patients with obstructive hypertrophic cardiomyopathy under optimal medical treatment has spawned the introduction of different techniques to reduce left ventricular outflow tract gradient and to relieve symptoms. Percutaneous septal ablation is a promising alternative to myotomy/myectomy surgery and to DDD pacemaker implantation for the treatment of obstructive hypertrophic cardiomyopathy with significant septal thickness and gradient (thickness always > 18 mm and gradient > 50 mmHg at rest) in the absence of intrinsic mitral disease or significant systolic dysfunction 1 in patients with limiting symptoms refractory to drug treatment, who refuse to undergo surgery or who have a high surgical risk.The procedure consisted of causing a septal infarction by injecting absolute alcohol into the first great perforating septal branch of the anterior descending artery, reducing septal thickness with fibrosis and relieving the obstructive component 2 . Although promising, this is still an experimental method, because less than 1,000 cases have been reported worldwide, and, in Brazil, only 5. Randomized comparative studies with the widely accepted transaortic invasive surgical technique are still lacking. The transaortic invasive surgical technique has an acceptable estimated mortality lower than 5%, ranging from 3% (large centers) to 15% 3,4 , and a mean complication rate of 6% of the patients operated on. The complications include significant residual aortic insufficiency, which is present in almost 4% of surgical patients 5 , endocarditis, complete left bundle-branch block, and total atrioventricular block.In this report, vector electrocardiographic alterations secondary to percutaneous septal ablation are described, the theoretical and anatomic bases of intraventricular dromotropic disorders are discussed, and they are compared with the alterations observed after transaortic myotomy/ myectomy surgery.