Endocardial radiofrequency ablation for hypertrophic obstructive cardiomyopathy: acute results and 6 months' follow-up in 19 patients.

OBJECTIVES: The purpose of this study was to examine the efficacy and safety of endocardial radiofrequency ablation of septal hypertrophy (ERASH) for left ventricular outflow tract (LVOT) gradient reduction in hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Anatomic variability of the vessels supplying the obstructing septal bulge can limit the efficacy of transcoronary ablation of septal hypertrophy in HOCM. Previous studies showed that inducing a local contraction disorder without reducing septal mass results in effective gradient reduction. We examined an alternative endocardial approach to transcoronary ablation of septal hypertrophy by using ERASH. METHODS: Nineteen patients with HOCM were enrolled; in 9 patients, the left ventricular septum was ablated, and in 10 patients, the right ventricular septum was ablated. Follow-up examinations (echocardiography, 6-min walk test, bicycle ergometry) were performed 3 days and 6 months after ERASH. RESULTS: After 31.2 ± 10 radiofrequency pulses, a significant and sustained LVOT gradient reduction could be achieved (62% reduction of resting gradients and 60% reduction of provoked gradients, p = 0.0001). The 6-min walking distance increased significantly from 412.9 ± 129 m to 471.2 ± 139 m after 6 months, p = 0.019); and New York Heart Association functional class was improved from 3.0 ± 0.0 to 1.6 ± 0.7 (p = 0.0001). Complete atrioventricular block requiring permanent pacemaker implantation occurred in 4 patients (21%); 1 patient had cardiac tamponade. CONCLUSIONS: ERASH is a new therapeutic option in the treatment of HOCM, allowing significant and sustained reduction of the LVOT gradient as well as symptomatic improvement with acceptable safety by inducing a discrete septal contraction disorder. It may be suitable for patients not amenable to transcoronary ablation of septal hypertrophy or myectomy.

Survival after transcoronary ablation of septal hypertrophy in hypertrophic obstructive cardiomyopathy (TASH): a 10 year experience.

BACKGROUND: Catheter-based treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM) by alcohol ablation (transcoronary ablation of septal hypertrophy, TASH) leads to symptomatic and haemodynamic improvement. However, little is known regarding the survival and its evolution since the introduction of the method in 1995. Theoretically, the method may be harmful, because widening of the obstructed left ventricular outflow tract is achieved by a septal infarction and subsequently by a potentially arrhythmogenic scar. OBJECTIVE: This study sought to determine the impact of TASH on the survival of all patients with HOCM treated in our institution between 1995 and 2005. METHODS: Survival was assessed from the early beginning in each of 644 consecutive patients to April 2005. Group A comprises a first series of 329 patients who were treated in a dose finding strategy with decreasing amounts of ethanol until December 2001, on average, from 2.9 ml to 0.93 ml/patient. The survival of this group was analysed using Kaplan-Meier estimates, multivariate Cox regression and Log-Rank testing. Group B comprises 315 patients of the following "low alcohol dose era" (mean amount of ethanol 0.8 +/- 0.4 ml, range 0.3-1.5 ml) and their mid-term survival (period to first regular 6-month post-procedural control). RESULTS: All patients (age 58 +/- 15 years, 99.2% follow up, mean 1.4 years): 33 patients died (5.1% all cause mortality), including perioperative deaths. 14/33 (42%) died from cardiac reasons. Annual total (all cause) mortality was 3.2%, total in-hospital mortality 1.2% in all patients (8 of 644 patients, 6 of them with severe comorbidity) and 0.4% in low risk patients. Annual cardiac mortality after hospital discharge was 0.7% (6 patients, all with sudden death). Group A (age 58 +/- 15 years, 98.8% follow up, mean 2.1 years, maximum 6.2 years): 29 patients died (total annual mortality 4.3%), 10 of them from hypertrophic cardiomyopathy related reasons resulting in a total in-hospital mortality of 1.8% (6 deaths), a cardiac annual mortality of 1.5% (including hospital mortality) and 0.6%/year after hospital discharge. Age was identified as an independent predictor of increased overall mortality (P = 0.002) and lower alcohol dosage and the absence of atrial fibrillation as independent predictors of reduced cardiac mortality (P = 0.005 and P = 0.039, respectively). With focus on the median value of the alcohol quantity (2.0 ml), patients treated with high amounts (>2.0 ml) showed a higher total mortality than patients treated with small amounts (< or =2.0 ml) (P = 0.031) and alcohol turned out to be an independent predictor of survival (P = 0.047). The same holds true for a homogenous subset of 262 patients with respect to cardiac mortality (P = 0.018). Group B (age 57 +/- 14 years, 99.7% follow up, mean 7.3 months): Total in-hospital mortality was 0.6% (2 of 315 patients; P = 0.173, group A/B) and cardiac in-hospital mortality 0% (P = 0.016, group A/B). During follow up two patients died, both of them experienced a sudden death reflecting an annual mortality of 1.0%. CONCLUSION: These data represent the largest available database on survival after alcohol septal ablation of HOCM from a single centre with large experience, and its evolution over 10 years with increasing procedural experience including the pronounced reduction of ethanol quantity in a systematic doses finding strategy. The in-hospital mortality has become very low. Cardiac survival during follow up was excellent, however, the well-known risk of sudden death is not completely eliminated. Longer follow-up time would be desirable for definite evaluation of this relatively new therapeutic option in the management of HOCM.

Predictors of complete heart block after transcoronary ablation of septal hypertrophy: results of a prospective electrophysiological investigation in 172 patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study analyzed changes in intracardiac conduction during transcoronary ablation of septal hypertrophy (TASH) to identify predictors for pacemaker dependency after TASH. BACKGROUND: Transcoronary ablation of septal hypertrophy is an accepted therapeutic option in hypertrophic obstructive cardiomyopathy (HOCM). However, atrioventricular conduction disorders, requiring permanent pacemaker implantation, remain a major adverse effect. METHODS: This study measured changes in intracardiac conduction in 172 consecutive patients during TASH by simultaneously recording electrophysiological parameters and correlated these parameters with the occurrence of complete heart block during continuous electrocardiographic monitoring for 8 days. RESULTS: Intraprocedural complete heart block occurred in 36 patients (20.1%) and was associated with a pre-existing bundle branch block (p = 0.010) or advanced age (p = 0.023). All patients with delayed complete heart block during follow-up (n = 15, 8.7%), occurring 1 to 6 days after TASH, showed lack of retrograde atrioventricular nodal conduction after TASH (p = 0.018). None of the patients with intact retrograde conduction after TASH developed delayed complete heart block. Further risk factors for delayed block were advanced age, intraprocedural complete heart block, and prolonged QRS duration before or after TASH (p < 0.05 for all). Permanent pacemaker implantation was performed in 20 patients. CONCLUSIONS: Measurement of intracardiac conduction during TASH improves the safety of the procedure by enabling identification of patients who are at risk of complete heart block after TASH. The duration of prophylactic temporary pacemaker backup should be prolonged up to day 6 after TASH in patients at increased risk (patients with retrograde atrioventricular block and at least 1 additional risk factor).

Transcoronary ablation of septal hypertrophy does not alter ICD intervention rates in high risk patients with hypertrophic obstructive cardiomyopathy.

INTRODUCTION: Transcoronary ablation of septal hypertrophy (TASH) is safe and effectively reduces the intraventricular gradient in patients with hypertrophic obstructive cardiomyopathy (HOCM). To analyze the potential of anti- and proarrhythmic effects of TASH, we studied the discharge rates of implanted cardioverter defibrillators (ICD) in patients with HOCM who are at a high risk for sudden cardiac death. METHODS: ICD and TASH were performed in 15 patients. Indications for ICD-implantation were secondary prevention in nine patients after resuscitation from cardiac arrest with documented ventricular fibrillation (n = 7) or sustained ventricular tachycardia (n = 2) and primary prevention in 6 patients with a family history of sudden deaths, nonsustained ventricular tachycardia, and/or syncope. All the patients had severe symptoms due to HOCM (NYHA functional class = 2.9). RESULTS: During a mean follow-up time of 41 +/- 22.7 months following the TASH procedure, 4 patients had episodes of appropriate discharges (8% per year). The discharge rate in the secondary prevention group was 10% per year and 5% in the group with primary prophylactic implants. Three patients died during follow-up (one each of pulmonary embolism, stroke, and sudden death). CONCLUSION: In conclusion, on the basis of ICD-discharge rates in HOCM-patients at high risk for sudden death, there is no evidence for an unfavorable arrhythmogenic effect of TASH. The efficacy of ICD treatment for the prevention of sudden cardiac death in HOCM could be confirmed, however, mortality is high in this cohort of hypertrophic cardiomyopathy patients.