Left Ventricular Mechanical Dyssynchrony Impairs Exercise Capacity in Patients With Coronary Artery Disease With Preserved Left Ventricular Systolic Function and a QRS Duration ≤120ms

Abstract

Background: Left ventricular (LV) mechanical dyssynchrony can lead to impairment of LV function and is associated with adverse clinical outcomes in coronary artery disease (CAD) patients. The impact of LV dyssynchrony on exercise capacity (EC) in patients with CAD was investigated. Methods and Results:An echocardiographic examination with tissue Doppler imaging and exercise treadmill testing in 151 CAD patients with normal LV ejection fraction was performed. LV intra- and inter-ventricular dyssynchrony were defined by the standard deviation of time interval between LV 6 basal segments (Ts-SD), and the time interval from the right ventricular (RV) free wall to LV lateral wall (Ts-RV) respectively, and EC was measured as metabolic equivalents (METs) on the treadmill. Patients with impaired EC (defined by a METs ≤8, which is the mean MET of the study population) were older (71±7 vs. 62±2 years, P<0.01), however, there were no differences in gender and clinical status such as prevalence of prior myocardial infarction (MI), regional wall motion abnormality (RWMA), and coronary revascularization between patients with (n=90) or without (n=61) impaired EC. Univariate analysis showed that age, body mass index, LV systolic and diastolic volume, mitral inflow A velocity, and Ts-SD were all significantly associated with METs (all P<0.05). However, multivariate regression analysis revealed that old age (odd ratio [OR]: 1.136, 95% confidence interval [CI]: 1.080-1.196, P<0.001), and Ts-SD (OR: 1.026, 95%CI: 1.003-1.049, P=0.027) only were independent predictors for impaired EC. Conclusions:In patients with CAD, LV systolic dyssynchrony predicts impaired EC independently of history of previous MI or RWMA. (Circ J 2012; 76: 682 - 688)

Impact of Physical Activity on Cardiovascular Events in Patients With Chronic Heart Failure

“…It has been reported that LV systolic dyssynchrony predicts impaired physical activity level, independently of history of previous MI or regional wall motion abnormality in patients with IHD. 22 In both stage A/B and C/D, the "high to high" group was characterized by younger age and high baseline level of physical activity. Additionally, the prevalence of valvular heart disease in stage A/B and the use of statins in stage C/D were significantly associated with the yearly change in physical activity level, although the clinical significance of these findings remains to be examined in future studies.…”

Left Ventricular Dyssynchrony by Three‐Dimensional Echocardiography: Current Understanding and Potential Future Clinical Applications

“…Resolution of LV mechanical dyssynchrony via cardiac resynchronization therapy (CRT) has been shown to significantly reduce the morbidity and mortality in patients with symptomatic systolic heart failure . In addition, mechanical dyssynchrony has been detected in various cardiac diseases such as hypertrophic cardiomyopathy and ischemic heart disease, and conditions such as diastolic heart failure, hypertension, and LV hypertrophy …”

Predictive value of left ventricular dyssynchrony for short-term outcomes in three-vessel disease patients undergoing coronary artery bypass grafting with preserved or mildly reduced left ventricular ejection fraction

“…It is important to identify additional indicators that can supplement risk stratification. The impairment of LV systolic synchrony is prevalent among CAD patients, and it can also occur in those patients with preserved or mildly reduced LVEF ( 26 – 28 ). In our study, the LV dyssynchrony parameters, including Tmsv16-SD%, Tmsv12-SD%, Tmsv16-Dif%, and Tmsv12-Dif% were higher in the group with short-term adverse outcomes.…”