Key result
Increasing body weight was significantly associated with a decline in active and passive resting tension in isolated human atrial myocardium (p < 0.0001), with a more pronounced effect in women.
Why the study?
Does increasing body weight correlate with decreased myocardial performance in isolated human atrial myocardium?
Cross-Sectional (n=183)
Does increasing body weight correlate with decreased myocardial performance in isolated human atrial myocardium?
Increasing body weight is associated with a significant decline in active and passive tension in isolated human atrial myocardium, suggesting a direct cardio-depressant effect of obesity.
Obesity may impair atrial contractility; this Level 5 observation in isolated tissue leaves open in vivo relevance and clinical impact.
OBJECTIVE: The present study was performed as an attempt to analyze the relationship between body weight and human myocardial performance. As overweight is frequently associated with hypertension, stenosis of epimyocardial coronary arteries and other factors that influence myocardial performance, the experimental model of isolated human atrial myocardium was selected. Atrial contractile performance does neither depend on the extent of stenosis of epicardial coronary arteries nor on the degree of hypertension and its secondary pathology. METHODS: Right atrial muscle preparations (0.5 x 6 mm) of 183 patients undergoing coronary artery bypass surgery were electrically stimulated at optimal length. Active tension (stimulation) and passive resting tension (relaxation) were measured (measurement conditions: 37 degrees C, Krebs-Henseleit solution, optimal length and supramaximal electrical stimulation). The relationship of body weight with the measured parameters was analyzed statistically by using linear regression model and Student's t-test. RESULTS: Active tension (mN/mm2) and passive resting tension (mN/mm(2)) declined significantly with increasing body weight (p < 0.0001). The ratio passive resting tension/active tension correlated significantly with body weight (p < 0.0001). The negative association between body weight and active tension amplitude was more pronounced in women (p < 0.05). The following linear regression was calculated: for men: force = -0.04 x body weight + 8.74 (R = 0.505, p < 0.0001, n = 106); for women: force = -0.08 x body weight + 12.03 (R = 0.717, p < 0.0001, n = 77). CONCLUSION: The experimental data are in accordance with the hypothesis, that obese tissue may exert a direct cardio-depressant effect on electromechanical coupling.
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Denk et al. (2009) conducted a cross-sectional in Coronary artery disease (undergoing CABG) (n=183). Increasing body weight vs. Lower body weight was evaluated on Active tension and passive resting tension (p=<0.0001). Increasing body weight was significantly associated with a decline in active and passive resting tension in isolated human atrial myocardium (p < 0.0001), with a more pronounced effect in women.
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