Heart Failure -> Cardiac Resynchronization Therapy: -> Surgical & Other D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-070 - Prolonged PR Segment And Not P-wave Duration Is Associated With Poor Outcome To Cardiac Resynchronization Therapy (ID 419)

 F.C. Salden: Nothing relevant to disclose.


Background: Previous studies showed that patients receiving cardiac resynchronization therapy (CRT) have a worse outcome if their PR interval is prolonged. PR interval is determined by atrial conduction (P-wave duration) and atrioventricular (AV) conduction velocity (PR segment).
Objective: To compare PR interval, P-wave duration and PR segment in association with clinical and echocardiographic outcomes in a large cohort of CRT patients.
Methods: A retrospective multicenter study was conducted in 633 CRT patients. PR interval, P-wave and PR segment (time between end P-wave and QRS onset) were determined from baseline 12-lead ECGs. Times were evaluated for their association with occurrence of all-cause mortality, left ventricular assist device implantation (LVAD) and cardiac transplantation (HTX) (combined primary endpoint). Secondary endpoint was echocardiographic reduction in LV end-systolic volume (LVESV).
Results: During a mean follow-up of 4.2 years 28% of patients reached the primary endpoint. These patients had a longer PR interval and PR segment compared to who did not reach the primary endpoint (median 206 vs 185ms and 62 vs 48ms, resp.; both P=0.000). P-wave duration was comparable in both groups. Patients with PR interval or PR segment >median reached the primary endpoint significantly more often and showed less echocardiographic response (figure).
Conclusion: The association of PR prolongation with poor clinical and echocardiographic response to CRT is predominantly determined by prolonged PR segment. These results may be explained by considering slow AV conduction as a marker of advanced cardiac disease and that slow atrial conduction has relatively a minor effect.