Single Beat Determination of Intraventricular Systolic Dyssynchrony in Patients with Atrial Fibrillation and Systolic Dysfunction.

BACKGROUND: Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia. However, diagnosis of intraventricular dyssynchrony in patients with AF is difficult due to beat-to-beat variation. Additionally, evaluation of mechanical dyssynchrony in the traditional method is based on average of 5 to 10 beats, which is exhausting and time consuming. Single-beat evaluation of a beat with equal subsequent cardiac cycles has been proposed as an accurate method in patients with AF. OBJECTIVES: We proposed to evaluate intraventricular mechanical dyssynchrony by measuring time-to-peak systolic velocity between basolateral and basoseptal segments (septum to lateral wall delay) using Tissue Doppler Study (TDI) by two different methods. MATERIALS AND METHODS: 31 patient (68 ± 10.3 years) with heart failure (EF < 35%) and AF rhythm, R-R cycle length more than 500 msec were evaluated. We found a target beat in which preceding R-R (R-R1) to pre-preceding R-R (R-R2) ratio was 1(RR1/RR2 = 1) then measured the intraventricular dyssynchrony in that cycle. Intraventricular dyssynchrony was also determined and averaged for 8 consecutive cardiac cycles. The values at RR1/RR2 = 1 were compared with the average of intraventricular dyssynchrony in eight cycles and the relationship between dyssynchrony were evaluated by paired T-test, linear Pearson correlation (r2), linear regression analysis. RESULTS: The average of dyssynchrony in eight cycles showed a positive correlation with dyssynchrony in target beat RR1/RR2 = 1. Average of dyssynchrony in target beat was 46.77 msec, and average of 8 cycle was = 47.701, (P value = 0.776, Pearson linear correlation 0.769). CONCLUSIONS: Measurement of intraventricular dyssynchromy in basoseptal and basolateral segments in AF and heart failure patients in a single beat with RR1/RR2 = 1 , were very similar to the average value of eight cardiac cycle.