Abstract 3576: Mechanical Dyssynchrony and the Relationship between QRS Duration, Left Ventricular Systolic Function and Time to Peak Aortic Flow: the Strong Heart Study
Background QRS duration on the surface electrocardiogram has been used to as a measure of ventricular mechanical dyssynchrony in the selection of heart failure patients for cardiac resynchronization therapy. It is not known whether components of the central arterial pressure waveform reflect ventricular mechanical dyssynchrony.
Methods We investigated the relationship between QRS duration, time to peak aortic flow (T1) on the central arterial pressure waveform (determined using radial applanation tonometry and a generalized transfer function; Figure⇓) and echo-derived left ventricular ejection fraction (EF) in 2,450 American Indian participants in the Strong Heart Study.
Results Participant characteristics were: age 40±17 years, 60% female, diabetes in 18% and hypertension in 32%. In univariate analysis, there was a significant positive association between QRS duration (93±14 msec.) and T1 (108±18 msec.; p<0.001) and a significant inverse association between QRS duration and EF (60±6%; p<0.001). Also, there was a significant inverse association between T1 and EF (p<0.001). In multivariate linear regression analysis, with EF and T1 as independent variables, the relationship between QRS duration and T1 remained significant (β0.06 per msec.T1; p<0.01).
Conclusions In this large population-based sample of adults, time to peak aortic flow on the central arterial pressure waveform is positively related to QRS duration, independent of EF. This suggests that analysis of the central arterial pressure waveform may play a role in the identification and treatment of ventricular mechanical dyssynchrony in patients being evaluated for cardiac resynchronization therapy.