Assessment of left atrial systolic dyssynchrony in paroxysmal atrial fibrillation and heart failure using cardiac magnetic resonance imaging: MESA study

Background

Left atrial (LA) remodeling in response to cardiovascular and hemodynamic stress may precede atrial fibrillation (AF) and heart failure (HF). We hypothesized that LA systolic synchronous contraction as a functional measure of LA remodeling is deranged in patients with paroxysmal AF and HF.

Methods

We performed a nested case-control analysis with 1:2 matching for 39 cases of paroxysmal AF (n=28, in sinus rhythm during cardiac magnetic resonance (CMR)) and HF (n=14, AF+HF; n=3) and 78 controls with similar demographic and clinical characteristics at the baseline (Table 1). LA circumferential (short axis) and longitudinal strain rate (horizontal long axis) were measured using Multi-modality Tissue Tracking (Toshiba, Japan) from short and long-axis cine CMR images. Circumferential LA systolic dyssynchrony among 18 LA segments (6 segments x 3 slices) was evaluated as; Standard Deviation (SD) of time to pre atrial contraction Strain rate (PreA Sr^c) and Peak systolic strain rate (Peak Sra^c) (Figure 1). Similarly, longitudinal LA dyssynchrony parameters (among 6 segments) were: SD-Time to pre-atrial contraction strain rate (PreA Sr^L) and SD-Time to peak systolic strain rate (Peak-Sra^L). Wilcoxon-rank sum test (non-parametric) or two sample t-test (parametric) were used for comparison between the groups.

Table 1 Left atrial circumferential and longitudinal systolic dyssynchrony parameters among the cases and the control group.

Figure 1

LA circumferential (panel A) and longitudinal (panel B) strain rate curves during a cardiac cycle using multimodality tissue tracking.

Results

In participants during MESA exam 5 (age 74±8 years, 51.4% men), systolic circumferential dyssynchrony (SD-TP-PreA Sr^c, msec) was significantly higher in the cases compared to controls (45.06 vs. 28.73, p<0.010). Similarly, case group had greater longitudinal dyssynchrony than controls; SD-TP PreA Sr^L (51.62 vs. 36.43, p=0.001) and SD-TP-Peak Sra^L (45.23 vs. 35.92, p=0.027) (Table 1).

Conclusions

Patients with paroxysmal atrial fibrillation and heart failure have significantly higher LA circumferential and longitudinal systolic dyssynchrony compared to normal controls.

Funding

N/A.