Potential triggering of Repetitive Nonreentrant Ventriculoatrial
Synchrony (RNRVAS) by loss of atrial capture.
Abstract
Background Data on the factors that trigger repetitive
non-reentrant ventriculoatrial synchrony (RNRVAS) are limited. We
hypothesize that loss of atrial capture may trigger RNRVAS. We aimed to
use an atrial threshold test to observe the development of RNRVAS upon
loss of atrial capture in patients with implantable cardiac electronic
devices (CIED). Methods Patients with DDD mode CIEDs [177
patients, 67.5 ± 14.8 (70) years; 70 women] were included. Atrial
threshold test was done in DDD mode at a rate at least 10 beats above
the basal heart rate, with an AV delay of 300 ms (range 250 - 350). A
multivariable logistic regression model was used to assess the
independent predictors of RNRVAS. Results RNRVAS was observed
in the 69 of 177 patients (39.0%). In patients with VA conduction,
incidence of RNRVAS increased to 76.7%. The patients with RNRVAS were
younger than those without RNRVAS ( P = .038). History of
complete AV block, any AV node conduction defect ( P <
.001) and ventricular pacing ratio ( P = .001) were significantly
higher and VA conduction ( P < .001) significantly less
in patients without RNRVAS than in patients with RNRVAS. History of
complete AV block ( P = .009) and ventricular pacing ratio (
P = .029) appeared as independent factors indicating decreased
risk of RNRVAS development. Conclusion In this study we
demonstrated that loss of atrial capture results in RNRVAS in one third
of patients with a CIED in DDD mode, and in three fourths of those with
VA conduction under certain predisposing CIED settings.