Doppler-derived cardiac performance and sequential electrocardiographic activation in patients with atrio-ventricular conduction disturbance and with normal conduction (DEEPER-PR study)

Background Delayed atrioventricular (AV) conduction impairs cardiac performance and promotes adverse outcomes. PR may not optimally reflect hemodynamic effects of AV activation. Objective To compare electrical conduction and Doppler-derived hemodynamics in patients with versus without first-degree AV block (AVB I°) and to evaluate hemodynamic reflection of PR and 6 novel measures of AV conduction. Methods We enrolled 52 patients with AVB I° (A) and 52 matched controls (B). Digitized electrocardiograms and echocardiographic variables were compared and evaluated. We characterized and ranked (correlations, logistic regression, Chi 2 ) the relationship between PR and novel measures of AV conduction and cardiac performance. Results PR differed between groups [A: 228 (212;251)ms, B: 182 (165;190)ms; p<0.001)], as did P duration [A: 127 (114;136,0)ms, B: 113 (103;127)ms; p<0.001], due to left atrial [A: 78 (64;102)ms, B: 69 (58;74)ms; p=0.012] and right atrial [A: 56 (44;63)ms, B: 47 (36;54)ms; p=0.023] delay. Compared to PR, and among other novel parameters, PePV6 (P offset in V1 to R peak in V6) superiorly reflected hemodynamics (LV filling fraction: PR Chi 2 11.67, PePV6 Chi 2 18.41, total LV isovolumic time: PR Chi 2 5.08, PePV6 Chi 2 14.53, Tei Index LV: PR Chi 2 2.26, PePV6 Chi 2 7.66). Similarly, PePV6 over PR and other parameters better predicted RV hemodynamics. Conclusion In this study, PR prolongation in AVB I° comprised delayed atrial and post-atrial AV conduction. The novel parameter of AV conduction PePV6, over PR, best reflected hemodynamic compromise due to delayed AV conduction. Further mechanistic and clinical evaluation of PePV6 and other novel parameters should be undertaken.