Reducing ventricular pacing in sinus node dysfunction.
BACKGROUND
The use of DDIR mode has been limited since the advent of mode switch in the DDDR mode. In patients with AV block, DDDR is necessary to maintain AV synchrony. However, DDIR mode may still be beneficial for patients with intact AV conduction. The aim of this study was to compare the incidence of ventricular pacing and atrial tachyarrhythmia in DDIR and DDDR with mode switch in a randomized, single-blind, crossover study, and discuss the utility of both modes.


RESULTS
Twenty-four patients (8 males) with bradycardia-tachycardia syndrome and no signs of AV block (mean age 70.1 +/- -9.1 years) were enrolled and randomized to DDIR or DDDR modes with the leads placed at the right atrial appendage and right ventricular apex. After 12 weeks, patients were switched to the opposite mode. During the study period, atrial high rate episodes and other pacemaker diagnostic data were collected. Significantly less ventricular pacing was observed in DDIR mode (DDIR versus DDDR; 48.9%, 76.5%, P = 0.0002) and atrial high rate episodes were significantly lower in DDIR mode (DDIR versus DDDR; 1.32, 1.85 per day, P < 0.05).


CONCLUSIONS
In patients with sinus node dysfunction and intact AV conduction, DDIR mode may have important implications for simplifying device programming, device longevity, and to avoid atrial tachyarrhythmia.
Ishikawa
Toshiyuki
T
Second Department of Internal Medicine, Yokohama City University Hospital, Yokohama.
Sumita
Shinichi
S
Kosuge
Masami
M
Giese
Chad
C
Markowitz
Toby
T
Tsunoda
Soichi
S
Uchino
Kazuaki
K
Kobayashi
Tsukasa
T
Matsushita
Kohei
K
Inoue
Noriko
N
Matsushita
Katsumi
K
Taima
Minoru
M
Kimura
Kazuo
K
Umemura
Satoshi
S
D000368:Aged; D000369:Aged, 80 and over; D001146:Arrhythmia, Sinus / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D018592:Cross-Over Studies; D018450:Disease Progression; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D012849:Sinoatrial Node / Q000503:physiopathology*; D016896:Treatment Outcome