Beneficial effects of biatrial pacing on cardiac function in patients with bradycardia -- tachycardia syndrome.
BACKGROUND
Biatrial (BiA) pacing prevents atrial fibrillation. By an unknown mechanism. The purpose of this study was to use Doppler echocardiography to evaluate the hemodynamic effects during BiA pacing.


RESULTS
The subjects were 7 patients with bradycardia - tachycardia syndrome with an implanted pacemaker. Atrial pacing sites were the right atrial appendage (RAA) and coronary sinus. P wave duration during BiA pacing (123 +/-16 ms) was significantly shorter than during either RAA pacing (167+/-19 ms, p<0.05) or sinus rhythm (148+/-12 ms, p<0.05). Doppler echocardiography revealed a greater cardiac output during BiA pacing than during RAA pacing (4.1+/-1.1 vs 3.5+/-0.7 L/min, p=0.042). The Doppler waveform of transmitral flow indicated that the left ventricular contraction interrupted the atrial filling wave during RAA pacing. The interval between the end of the atrial filling wave of transmitral flow and the mitral valvular closing sound was significantly increased by BiA pacing compared with RAA pacing (56+/-65 vs 40+/-57 ms, p=0.047).


CONCLUSIONS
Cardiac hemodynamics were improved by BiA pacing and reduction of left atrial load may be one of the mechanisms.
Second Department of Internal Medicine, Yokohama City University School of Medicine, Yokohama, Japan. birth-45@fukuhp.yokohama-cu.ac.jp
Katsumi
K
Matsumoto
Toshiyuki
T
Ishikawa
Shinichi
S
Sumita
Kohei
K
Matsushita
Noriko
N
Kawasaki
Tsukasa
T
Kobayashi
Kazuaki
K
Uchino
Kazuo
K
Kimura
Satoshi
S
Umemura
D000368:Aged; D020517:Atrial Appendage / Q000000981:diagnostic imaging; D016275:Atrial Function; D001783:Blood Flow Velocity; D001919:Bradycardia / Q000000981:diagnostic imaging / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D010138:Pacemaker, Artificial; D011859:Radiography; D013577:Syndrome; D013610:Tachycardia / Q000000981:diagnostic imaging / Q000628:therapy*; D014463:Ultrasonography