Key result
Optimal AV delay shows no significant change between rest and exercise in complete AV block.
Why the study?
Optimal programming of the rate-adaptive atrioventricular delay in patients with atrioventricular block is unclear and requires investigation.
Does submaximal exercise significantly change the optimal AV delay in DDD pacemaker patients with third-degree AV block compared to rest?
Observational (n=20)
Does submaximal exercise significantly change the optimal AV delay in DDD pacemaker patients with third-degree AV block compared to rest?
In patients with third-degree AV block and preserved EF, optimal AV delay does not significantly change between rest and submaximal exercise, indicating that a universal recommendation for rate-adaptive AV delay programming cannot be provided.
May inform individualized AV delay programming in preserved-EF DDD pacing; leaves open prospective outcome validation.
AIM: To optimize recommendations for programming of the rate-adaptive atrioventricular (AV) delay. METHODS AND RESULTS: Optimal AV delay (AVD(opt)) is the net effect of the pacemaker-related interatrial conduction time (IACT), duration of the left-atrial electromechanical action (LA-EAC(long)) and duration of left-ventricular latency (S(V)-EAC(short)). It can be calculated by AVD(opt) = IACT + LA-EAC(long)-S(V)-EAC(short). We measured these three components in 20 DDD pacemaker patients (EF >45%) with the third degree AV block (AVB) at rest and submaximal ergometric exercise load of 71 +/- 9 W which resulted in a 31.5 +/- 9.9 bpm rate increase. Between exercise and rest, the components of and the final AVD(opt) showed no significant differences. Interatrial conduction time in VDD and DDD pacing varied by 2.3 +/- 8.4 ms and 1.4 +/- 8.8 ms, respectively, S(V)-EAC(short) changed by -2.6 +/- 21.8 ms and AVD(opt) by -3.5 +/- 33.3 ms and -4.3 +/- 37.8 ms in VDD and DDD operation, respectively. The greatest variation was of LA-EAC(long) by -8.4 +/- 32.7 ms. Linear regressions of the rate-dependent variations (Deltaf) in VDD operation yielded DeltaIACT(f) = 0.04Deltaf + 0.95 ms, DeltaLA-EAC(long) = -0.59Deltaf + 10.1 ms, and DeltaS(V) - EAC(short) = 0.14Deltaf -7.2 ms which resulted in DeltaAVD(opt) = -0.69Deltaf + 18.2 ms. CONCLUSION: A recommendation for programming of rate-adaptive AV delay in AV block patients cannot be given.
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Melzer et al. (2007) conducted an observational in Third degree atrioventricular block (n=20). Submaximal ergometric exercise vs. Rest was evaluated on Optimal AV delay (AVD(opt)). In patients with third-degree AV block, optimal AV delay showed no significant differences between rest and submaximal exercise, precluding a uniform programming recommendation.
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