Patients with severe aortic stenosis are classified according to flow-gradient patterns. We investigated whether left ventricular (LV) mechanical dispersion, a marker of dyssynchrony and predictor of mortality, is associated with low-flow status in aortic stenosis. 316 consecutive patients with aortic stenosis and QRS duration < 120 ms were included in the retrospective analysis. Patients with severe aortic stenosis (aortic valve area ≤ 1.0 cm 2) were classified as normal-flow (NF; stroke volume index > 35 ml/m 2) high-gradient (HG; mean transvalvular gradient ≥ 40 mmHg) (n = 79), NF low-gradient (LG) (n = 62), low-flow (LF) LG ejection fraction (EF) ≥ 50% (n = 57), and LF LG EF < 50% (n = 23). Patients with moderate aortic stenosis (aortic valve area 1.5-1.0 cm 2 ; n = 95) served as comparison group. Mechanical dispersion (calculated as standard deviation of time from Q/S onset on electrocardiogram to peak longitudinal strain in 17 left ventricular segments) was similar in patients with NF HG (49.4 ± 14.7 ms), NF LG (43.5 ± 12.9 ms), LF LG EF ≥ 50% (47.2 ± 16.3 ms) and moderate aortic stenosis (44.2 ± 15.7 ms). In patients with LF LG EF < 50%, mechanical dispersion was increased (60.8 ± 20.7 ms, p < 0.05 vs. NF HG, NF LG, LF LG EF ≥ 50% and moderate AS). Mechanical dispersion correlated with global longitudinal strain (r = 0.1354, p = 0.0160) and heart rate (r = 0.1587, p = 0.0047), but not with parameters of aortic stenosis. Mechanical dispersion was similar among flow-gradient subgroups of severe aortic stenosis with preserved LVEF, but increased in patients with low-flow low-gradient and reduced LVEF. These findings indicate that mechanical dispersion is rather a marker of systolic myocardial dysfunction than of aortic stenosis.

Purpose Patients with severe aortic stenosis are classified according to flow-gradient patterns. We investigated whether left ventricular (LV) mechanical dispersion, a marker of dyssynchrony and predictor of mortality, is associated with low-flow status in aortic stenosis. Methods and results 400 consecutive patients with QRS duration &lt;120ms were included in the retrospective analysis. Patients with severe aortic stenosis (aortic valve area ≤1.0cm2) were classified as normal-flow (NF; stroke volume index &gt;35ml/m2) high-gradient (HG; mean transvalvular gradient ≥40mmHg) (n=79), NF low-gradient (LG) (n=62), low-flow (LF) LG ejection fraction (EF) ≥50% (n=57), and LF LG EF&lt;50% (n=23). Patients with moderate aortic stenosis (aortic valve area 1.5–1.0cm2; n=95) and patients with chronic systolic heart failure (n=84) without aortic stenosis served as comparison groups. Similar values of mechanical dispersion (calculated as standard deviation of time from Q/S onset on electrocardiogram to peak longitudinal strain in 17 left ventricular segments) was observed in patients with NF HG (49.4±14.7ms), NF LG (43.5±12.9ms), LF LG EF≥50% (47.2±16.3ms) and moderate aortic stenosis (44.2±15.7ms). Mechanical dispersion was increased in patients with LF LG EF&lt;50% (60.8±20.7ms) and in chronic heart failure (59.4±16.7ms) (p&lt;0.05 for both vs. NF HG‡, NF LG†, LF LG EF≥50%§ and moderate*; Figure). Mechanical dispersion correlated with LV end-systolic volume index (r=0.2530, p&lt;0.0001), LVEF (r=−0.2895, p&lt;0.0001) and global longitudinal strain (r=0.3108, p&lt;0.0001), but not with parameters of aortic stenosis. Conclusion Mechanical dispersion was similar among flow-gradient subgroups of severe aortic stenosis with preserved LVEF, but increased in patients with low-flow low-gradient and reduced LVEF. These findings indicate that mechanical dispersion is rather a marker of systolic myocardial dysfunction than of aortic stenosis. Figure 1 Funding Acknowledgement Type of funding source: None