Nonsurgical reduction of the interventricular septum in patients with hypertrophic cardiomyopathy.
BACKGROUND
In patients with hypertrophic cardiomyopathy and obstruction of the left ventricular outflow tract, nonsurgical reduction of the septum is a treatment option when medical therapy has failed. We investigated the long-term effects of nonsurgical reduction of the septum on functional capacity and electrocardiographic and echocardiographic characteristics.


METHODS
Sixty-four consecutive patients with hypertrophic cardiomyopathy and a mean (+/-SD) age of 48.5+/-17.2 years underwent nonsurgical reduction of the septum by injection of ethanol into the septal perforator branch of the left anterior descending coronary artery. These patients were assessed by exercise testing, electrocardiography, and resting and dobutamine (stress-induced) echocardiography after a mean period of 3.0+/-1.3 years.


RESULTS
At follow-up, patients had significant improvements in New York Heart Association class, peak oxygen consumption (from 18.4+/-5.8 to 30.0+/-4.4 ml per kilogram of body weight per minute, P<0.001), and left ventricular outflow tract gradients (resting gradient, from 64+/-36 to 16+/-15 mm Hg; P<0.001; stress-induced gradient, from 132+/-34 to 45+/-19 mm Hg; P<0.001). Procedure-related complications included right bundle-branch block in all patients, complete heart block in 31 patients (48 percent), and significant increases in QRS and corrected QT intervals. Seventeen patients (27 percent) required permanent pacing. R-wave amplitude was significantly decreased (from 32+/-8 to 17+/-7 mV, P<0.001). The dimensions of the left ventricular cavity increased, and the interventricular septal thickness was reduced.


CONCLUSIONS
Nonsurgical septal reduction leads to sustained improvements in both subjective and objective measures of exercise capacity in association with a persistent reduction in resting and stress-induced left ventricular outflow tract gradients. It is also associated with a high incidence of procedure-related complete heart block, however, often requiring permanent pacing.
Shamim
Waqar
W
National Heart and Lung Institute, Royal Brompton and Harefield Hospital, Imperial College of Science, Technology and Medicine, London.
Yousufuddin
Mohammed
M
Wang
Duolao
D
Henein
Michael
M
Seggewiss
Hubert
H
Flather
Marcus
M
Coats
Andrew J S
AJ
Sigwart
Ulrich
U
D000704:Analysis of Variance; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D025401:Echocardiography, Stress; D004562:Electrocardiography; D000431:Ethanol / Q000627:therapeutic use*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000503:physiopathology; D006346:Heart Septum / Q000000981:diagnostic imaging; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000139:chemically induced; D016896:Treatment Outcome
D000431:Ethanol