Short-term Efficacy Of Percutaneous Transluminal Septal Myocardial Ablation On Hypertrophic Obstructive Cardiomyopathy

1. BackgroundHypertrophic obstructive cardiomyopathy (UOC'M) is characterized by asymmetric hypertrophy of the interventricular septum (IVS), a narrowed left ventricular outflow tract (LVOT) and the subsequent symptoms caused by the obstruction of LVOT. Reducing the left ventricular outflow gradient (LVOTG) is the clinical aim for symptomatic patients with HOCM. Some drug-refractory patients may benefit from the implantation of a DDD pacemaker, wilh a decrease in LVOTG and improvement of symptoms. However, this therapeutic option is not generally recommended. Seplal myectomy is an effective method, but has a high perioperation mortality Percutaneous transluminal septal myocardial ablation (I'TSMA) is a promising non-surgical procedure carried out in recent years, wilh minimal injury, high sai'ety and the same effectiveness as surgical myectomy.2. Objectiveto evaluate the Short-term efficacy of PTSMA on HOCM.3. MethodsPTSMA was performed by Sigwart method in fifty patients with HOCM(8 males. 7 females, mean age 44.6 11.3 years) hospitalized from September, 1999 to July, 2003. The changes left ventricular outflow-tract gradient ( LVOTG) and ECG were measured before and after septal branches were occluded by absolute alcohol . The thickness of septal myocardium (IVSj) , left atrial size (LA) , velocity of left ventricular outflow tract ( LVOT-V ) . stroke volume ( SV) and ejection fraction( EF) were also measured by echocardiography before and after PTSMA. Cardiac enzyme were tested after PTSMA. 4. ResultsThe average LVOTGs at rest and after ventricular premature beats were significantly reduced from (70.6 30.6)mmHg and (128.1 41.0)mmHg respectively before the procedure to (11.3 14.7)mmHg and (30.3 3 1.4)mmHg respectively after the procedure (P< 0.01). LVOT-V reduced from ( 3.9 1.0 ) m/s to ( 3.1 1.0 ) m/s ( P< 0.01). Whereas IVSd . LA. SV. and EF had no significant difference after abiation(P > 0.05 ). Premature ventricular beats, nonsustained ventricular tachycardia, complete atrioventricular block and bundle branch block were observed during and after ablation. VV1 pacemakerwas implanted in one patient because of permanent completeatnoventncular block. Severe hemodynamic obstruction occurred in onecase.5. ConclusionPTSMA can significantly reduced LVOTG and LVOT-V and has a satisfactory short-term efficacy in the treatment of HOCM. Further studies on middle and long-term efficacy should be done.