Predictors of complete heart block after transcoronary ablation of septal hypertrophy: results of a prospective electrophysiological investigation in 172 patients with hypertrophic obstructive cardiomyopathy.
OBJECTIVE
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).
Lawrenz
Thorsten
T
Klinikum Bielefeld-Mitte, Department of Cardiology and Internal Intensive Care, Bielefeld, Germany. thorsten.lawrenz@sk-bielefeld.de
Lieder
Frank
F
Bartelsmeier
Markus
M
Leuner
Christian
C
Borchert
Bianca
B
Meyer zu Vilsendorf
Dorothee
D
Strunk-Mueller
Claudia
C
Reinhardt
Jens
J
Feuchtl
Andre
A
Stellbrink
Christoph
C
Kuhn
Horst
H
D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000628:therapy*; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006327:Heart Block / Q000453:epidemiology* / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006346:Heart Septum / Q000473:pathology*; D006801:Humans; D006984:Hypertrophy; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D012307:Risk Factors