Progressive decrease of outflow gradient and septum thickness after percutaneous alcoholization of the interventricular septum in hypertrophic obstructive cardiomyopathy.

BACKGROUND

The aim of this study was to evaluate the immediate- and mid-term results of percutaneous transluminal septal myocardial ablation (PTSMA) of the interventricular septum performed in 15 consecutive patients with hypertrophic obstructive cardiomyopathy between 1996 and 1999.

METHODS

Prior to intervention, all patients (7 males, 8 females, mean age 62 +/- 11 years) complained of severe dyspnea (NYHA functional class III-IV) despite medical treatment with beta-blockers and/or verapamil. Family history of hypertrophic cardiomyopathy was present in 2 cases. Dehydrated alcohol (4.8 +/- 1.5 ml/pt) was selectively infused into the first septal perforator artery through over-the-wire balloon catheters. In 5 patients a second or a third septal branch was treated because the intraventricular gradient persisted above 50 mmHg after the initial alcohol infusion.

RESULTS

Alcohol infusion induced an average peak creatine phosphokinase level of 1,524 +/- 427 IU/l. No iterating ventricular arrhythmias occurred during the procedure or in the 2-3 days of continuous ECG monitoring after the procedure. Two patients (13%) developed a complete atrioventricular block after the procedure, requiring permanent double-chamber pacing. Electrocardiographic changes included a > 2 mm ST segment elevation and transient right bundle branch block or left anterior/left posterior hemiblock in all patients. Peak basal intraventricular gradient decreased from 80 +/- 27 to 24 +/- 27 mmHg (p < 0.01) during cardiac catheterization and from 81 +/- 27 to 35 +/- 25 mmHg (p < 0.01) at the echocardiographic control performed during the hospital stay. At follow-up (mean 5.1 +/- 3.6 months), all patients were in NYHA functional class I or II. Repeat echocardiography showed a further significant decrease in intraventricular gradient to 25 +/- 26 mmHg (p < 0.01) and a progressive decrease in intraventricular septum thickness (25 +/- 5 mm before treatment, 21 +/- 6 mm before hospital discharge, 17 +/- 3 mm at follow-up, p < 0.01).

CONCLUSIONS

PTSMA of the intraventricular septum effectively relieves symptoms in selected patients with hypertrophic obstructive cardiomyopathy. The immediate decrease in intraventricular gradient is followed by a further decline at follow-up with a progressive reduction in the intraventricular septum thickness.