Left ventricular endocardial pacing predicts the reduction of left ventricular outflow tract pressure gradient immediately after percutaneous transseptal myocardial ablation in patients with hypertrophic obstructive cardiomyopathy refractory to medication.
BACKGROUND
Hypertrophic obstructive cardiomyopathy (HOCM) carries an increased risk for sudden cardiac death. No data regarding the percutaneous transseptal myocardial ablation (PTSMA) and epicardial left ventricular pacing (LVP) were reported.


METHODS
Seven patients with recurrent symptoms and increased resting left ventricular outflow tract pressure gradient (LVOTG) after PTSMA and another 14 patients with HOCM without history of PTSMA were studied. Both resting and dobutamine stress echocardiography, PTSMA and LVP were routinely performed.


RESULTS
In patients without previous PTSMA procedure, mild reduction of resting LVOTG was detected at 5 minutes after left ventricular pacing, and this reduction became significant at 10 minutes. All patients were divided into successful and unsuccessful groups according to their response to LVP. In contrary to patients in unsuccessful group, resting and R-S2 stimuli-induced LVOTG during PTSMA procedure were decreased dramatically ((9 +/- 5) mmHg vs (58 +/- 12) mmHg, (12 +/- 2) mmHg vs (113 +/- 27) mmHg, P < 0.001). Analysis of Logistic regression demonstrated that only LVOTG level during left ventricular pacing was an independent factor predicting the reduction of LVOTG immediately after PTSMA (odds ratio (OR), 0.59; 95% CI 2.67 to 5.82; P = 0.0002).


CONCLUSIONS
Left ventricular endocardial temporary pacing plays a critical role in predicting acute effect on the reduction of LVOTG immediately after PTSMA procedure.
Chen
Shao-liang
SL
Department of Cardiology, Nanjing First Hospital of Nanjing Medical University, Nanjing 210006, China. chmengx@126.com
Dai
Zhen-lin
ZL
Li
Zhan-quan
ZQ
Hu
Zuo-Ying
ZY
Ye
Fei
F
Zhang
Jun-jie
JJ
Zhang
Fen-fu
FF
Luo
Jun
J
Zhu
Zhong-sheng
ZS
Lin
Song
S
Wu
Cheng-quan
CQ
Tian
Nai-liang
NL
D000328:Adult; D002304:Cardiac Pacing, Artificial; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D017115:Catheter Ablation; D004452:Echocardiography; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011312:Pressure; D016277:Ventricular Function, Left