The Effect of Application of Negative Hysteresis AV Delay on Duration of QRS in Cardiac Resynchronization Therapy patients

Abstract

The aim of the present study was to investigate the effect of application of negative hysteresis AV Delay on duration of QRS as an indicator of synchronization in patients undergoing CRT. Materials and methods: In a descriptive-analytical study, 30 patients who underwent CRT at Shahid Madani Educational-Medical Center of Tabriz University of Medical were included in the study. The CRT device was set in intrinsic method and also set on negative AV hysteresis method with reduction of 30, 50, 80 and 110 ms in AV delay. Finally, in each of the mentioned methods, QRS widths were measured and compared with each other and with the patient's intrinsic QRS width. QRS duration was measured in each method with Screen Caliper software and the resulting data were collected and recorded. Results: The mean age of patients was 61.77±11.91 years in the range of 36 to 80 years old. 13 patients (43.3%) were male and 17 patients (56.7%) were female. The average duration of QRS in all leads before implantation of CRT was 150.53±16.33 in the range of 131 to 200 milliseconds, after implantation of CRT and in intrinsic mode was 150.10±29.03 in the range of 80 to 232 milliseconds, after implantation CRT was 127.53±23.23 in the range of 91 to 178 ms and in the negative AVD hysteresis mode with reduction 80 ms of AVD was 124.33±19.70 in the range of 90 to 168 ms. The use of negative AVD hysteresis significantly reduced the mean of leads QRS duration (P=0.001, CI95%: 115.83-132.90).