Clinical benefit of rigorous atrioventricular delay optimisation in patients with a dual chamber pacemaker. The role of an interatrial conduction delay in left atrioventricular asynchrony.

Abstract

In case of an interatrial conduction delay (IACD), the left ventricle will contract before the left atrial contraction has ended and the mitral valve will close prematurely. This leads to left atrioventricular dyssynchrony. An IACD is frequent in pacemaker patients, but often neglected during follow-up. Therefore, the atrioventricular delay (AVD) will be left at nominal values which are usually too short. Consequently, these patients develop left atrioventricular dyssynchrony, causing dizziness, fatigue and dyspnoea. This could be prevented by lengthening the AVD. Otherwise, some of the patients have a too long AVD, leading to a suboptimal diastolic filling time. In these patients, the optimal AVD could be achieved by shortening the delay.

Previous studies showed beneficial hemodynamic effects after AVD optimisation in cardiac resynchronisation therapy, biatrial and dual chamber pacemaker patients. We hypothesised that AVD optimisation would result in a better clinical outcome and left atrial function in dual chamber pacemaker patients.

We set up a randomised cross-over study in which we optimised the AVD via transthoracic echocardiography (TTE). The benefit of optimisation was evaluated through an ergospirometry, a 6 minute walk test, TTE, HeartQoL questionnaire, NYHA class and BNP.

Our study showed that individualised AVD optimisation by TTE improved the functional capacity and thus should be considered in every dual chamber pacemaker patient.