Author + information
- L. Cassaniti1,
- G. Romano2,
- G. Busacca1,
- G.F. Muscio2,
- F. Di Gregorio3,
- M. Contarini2 and
- G. Licciardello1
Atrial contraction timing should be considered in AV-delay setting, to avoid AV-valve closure before the end of active filling.
Tricuspid and mitral flows were assessed by echo-Doppler in 22 pacemaker patients, measuring the latency between P-wave onset and A-wave onset and end (P-Aon; P-Aend). Implants were all dual-chamber, with leads in right appendage and apex.
With atrial sensing (As), the tricuspid flow featured P-Aon and P-Aend of 71±43 and 241±77 ms, respectively (mean±sd). These latencies increased to 119±57 and 304±88 ms in pacing (Ap). Mitral P-Aon and P-Aend were 94±6 and 281±69 ms with As, and 131±53 and 330±65 ms with Ap. All pacing-induced increments were significant (P<2*10-5; paired t-test). The figures show sensed and paced P-Aend distribution. In 55% of the cases, any paced AV delay <128 ms entailed mitral A-wave shortening, suggesting ventricular interference on active filling.
The latency to end of mitral or tricuspid A-wave can be long in a relevant fraction of patients, particularly after Ap. Echocardiographic evaluation is advisable before programming a short AV delay, which might affect the active flow.