Percutaneous septal ablation for symptomatic hypertrophic obstructive cardiomyopathy: managing the risk of procedure-related AV conduction disturbances.
OBJECTIVE
To provide tools for predicting the course of AV conduction disturbances after ethanol-induced septal ablation (PTSMA) for hypertrophic obstructive cardiomyopathy (HOCM).


RESULTS
Based on a scoring system developed 1996-1998 and including parameters from baseline ECG, heart rate profile, severity of outflow obstruction (LVOTO), peri-interventional enzyme kinetics, and peri-interventional conduction problems, the risk of permanent AV block following PTSMA was assessed in 155 consecutive HOCM patients (pts.; mean age: 53+/-13 years) between 1999 and 2004. During PTSMA with 2.1+/-0.5 ml of ethanol, transient complete AV block occurred in 71 pts. (46%). Pts. were grouped into a low, intermediate, and high risk group for permanent conduction damage, and treated accordingly (early discharge from monitoring, prolonged monitoring, early DDD-PM implantation). Permanent pacing was necessary in 11 cases (7%), 0/116 of these (0%) in the low, 4/31 (13%) in the intermediate, and 7/8 (87%) in the high-risk group. While a new right bundle branch block was the most frequent ECG finding after PTSMA, a left bundle branch block at baseline was associated with 4 of the 11 DDD-PM implantations (p<0.0001). In-hospital mortality was 0%, short-term (3-months) follow up was complete. During follow-up, AV conduction recovered in 4 pts. (46%) with a DDD-PM. New onset AV blocks did not occur. Significant improvement of symptoms was reported by 141 pts. (91%).


CONCLUSIONS
Catheter-based septal ablation is an effective non-surgical technique for reducing symptoms and outflow gradients in HOCM. The proposed scoring system appears to reliably discriminate pts. with a high risk for permanent PM dependency from those with stable AV conduction after PTSMA. Pts. with left bundle branch block at baseline should undergo DDD-PM implantation prior to ablation.
Faber
Lothar
L
Department of Cardiology, Heart and Diabetes Center NRW, Ruhr-University Bochum, Georgstr. 11, D-32545 Bad Oeynhausen, Germany. lfaber@hdz-nrw.de
Welge
Dirk
D
Fassbender
Dieter
D
Schmidt
Henning K
HK
Horstkotte
Dieter
D
Seggewiss
Hubert
H
D000704:Analysis of Variance; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000188:drug therapy*; D003287:Contrast Media; D015150:Echocardiography, Doppler; D000431:Ethanol / Q000008:administration & dosage*; D005260:Female; D006327:Heart Block / Q000139:chemically induced* / Q000517:prevention & control*; D006346:Heart Septum; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides; D012307:Risk Factors; D016896:Treatment Outcome
D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508; D000431:Ethanol