[Clinical features of five patients with delayed third degree atrioventricular block after ethanol septal ablation for hypertrophic obstructive cardiomyopathy].
OBJECTIVE
To analyze the clinical features of patients with delayed third degree atrioventricular block after ethanol septal ablation for hypertrophic obstructive cardiomyopathy.


METHODS
The clinical data of cases with delayed third degree atrioventricular block after septal ablation for hypertrophic obstructive cardiomyopathy at our hospital from 2000 to 2011 were collected.


RESULTS
Five out of 235 patients (2.1%) developed delayed third degree atrioventricular block. Delayed third atrioventricular block occurred at 32 h post ablation (28 - 120 h). Their average age is 46 (33 - 64) years old, there are 4 males and 1 female. Left ventricular outflow gradient before ablation was 70 - 100 mm Hg (1 mm Hg = 0.133 kPa). Intraprocedural third degree atrioventricular block occurred in 4 patients. The average injected dose of Ethanol was 1.8 (1.4 - 4.3) ml. Syncope occurred in 3 patients. Temporary pacemaker was reimplanted to all 5 patients and removed after an average of 8 d (3 - 18 d). All 5 patients were in normal sinus rhythms at discharge without the need of implanting permanent pacemaker. There was no syncope in these 5 patients after discharge during the telephone follow up for an average of 9 (1 - 72) months.


CONCLUSIONS
The incidence of delayed third degree atrioventricular block after septal ablation is rare. Prolonged electrocardiography monitoring and prophylactic temporary pacemaker backup post ablation are necessary to detect this event and to prevent syncope related to delayed third degree atrioventricular block after septal ablation.
Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
Rong
R
Liu
Shu-bin
SB
Qiao
Feng-huan
FH
Hu
Wei-xian
WX
Yang
Jian-song
JS
Yuan
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000628:therapy*; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D006327:Heart Block / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies