The effect of pharmacological stress on intraventricular dyssynchrony in left ventricular systolic dysfunction

Abstract

Background: Cardiac resynchronisation therapy (CRT) improves symptoms and exercise capacity in many patients with heart failure (HF) who have left ventricular systolic dysfunction (LVSD) and markers of dyssynchrony. LV dyssynchrony is conventionally measured at rest but the symptoms of heart failure occur predominantly on exercise. Induction or exacerbation of dyssynchrony during stress might identify additional patients who could benefit from CRT. Methods and results: Seventy-seven patients (47 with QRSd b 120 ms and 30 with QRSd N 120 ms) with heart failure due to left ventricular systolic dysfunction and 22 normal subjects underwent dobutamine stress echocardiography using colour tissue Doppler imaging. Left intraventricular dyssynchrony was measured as the standard deviation of the time to peak velocity from the onset of the QRS (Ts-SD) and the difference between the maximum and minimum time to peak velocity (Tscor-diff) in the 12 non-apical segments at rest and during peak stress. Timings were corrected for heart rate. The mean values of these indices increased with stress in both groups of patients but not in control subjects ( p b 0.001). The prevalence of conventionally-defined dyssynchrony also increased with stress. Conclusion: In patients with heart failure, the severity and the prevalence of intraventricular dyssynchrony increase with stress. Whether stress-induced dyssynchrony will identify patients who might benefit from CRT awaits further research.

Response of Functional Mitral Regurgitation during Dobutamine Infusion in Relation to Changes in Left Ventricular Dyssynchrony and Mitral Valve Geometry

“…Third, LV mechanical dyssynchrony trends toward a deteriorated state as heart rate increases in patients with non-ischemic LV systolic dysfunction 23,24. As both exercise and dobutamine stress increase heart rate, the increased response of LV dyssynchrony during both exercise and dobutamine stress in DCM might be associated with increased heart rate 8,9,25. Nevertheless, the maximal heart rate achieved by dobutamine stress in the present study seemed to be lower than that by exercise in previous studies 9,12,14.…”

Synchronicity of systolic deformation in healthy pediatric and young adult subjects: a two-dimensional strain echocardiography study

“…Correction for the influence of variation in heart rate on time to peak systolic strain values was achieved by dividing time to peak systolic strain measurements by the square root of the R-R interval in these subjects (i.e., Bazett's formula; Refs. 7,18,32,66). All offline measurements with EchoPAC were performed by a single observer (K. A. Marcus).…”

Cardiac resynchronization therapy: dyssynchrony imaging from a heart failure perspective

“…However, ultimately it may be our lack of understanding about the nature of cardiac dyssynchrony that is the problem. A recent study [79 ] shows that stress will induce dyssynchrony in most dilated dysfunctional LV. Thus, dyssynchrony may be a near-universal problem of the diseased LV, in which case there is no need to try to detect it.…”