DIAGNOSTIC-VALUE OF LEFT-VENTRICULAR DYSSYNERGY PATTERNS IN ISCHEMIC AND NONISCHEMIC CARDIOMYOPATHY

Background: The distinction between ischemic and non-ischemic cardiomyopathy has important clinical implications. The objective of the present study was to investigate whether left ventricular dyssynergy patterns, detected by quantitative analysis of ultrasound images, differed in these two pathological processes. Methods: Fifty-six consecutive patients with congestive heart failure (New York Heart Association functional class II-IV) secondary to depressed left ventricular systolic function (ejection fraction less-than-or-equal-to 35% during diagnostic cardiac catheterization) were studied. Twenty patients were eliminated from further analysis because they met one or more exclusion criteria. The remaining 36 were divided into two groups based on the presence (ischemic cardiomyopathy) or absence (non-ischemic cardiomyopathy) of a greater-than-or-equal-to 50% narrowing of the luminal diameter in one or more coronary arteries. In all patients, a standard two-dimensional echocardiographic study was obtained. Apical four- and two-chamber views with optimal endocardial and epicardial resolution were selected for analysis, and the left ventricular contour was divided into six segments of interest. Optimal endocardial and epicardial resolution were defined according to an original internal quality score system. For each of the six segments of interest, regional ejection fraction and regional segmental thickening were estimated. Data analysis was then performed on the average values of regional ejection fraction and regional segmental thickening obtained across the entire left ventricular contour. In each patient, regional ejection fraction range and regional segmental thickening range were calculated by subtracting the minimum from the maximum value of regional ejection fraction and regional segmental thickening obtained across a left ventricular contour. Results: Regional ejection fraction and regional segmental thickening did not differ significantly between the two groups. However, regional ejection fraction range and regional segmental thickening range were significantly greater in patients with ischemic cardiomyopathy than in patients with non-ischemic cardiomyopathy [28.32+/-11.17 versus 14.74+/-7.73% (P<0.001) and 47.80+/-16.00 versus 24.64+/-9.39% (P<0.001), respectively]. Overlap of findings was observed in 20% of the values for regional ejection fraction range but in only 14% of those for regional segmental thickening range. Conclusions: Patients with ischemic cardiomyopathy demonstrate a non-uniform dyssynergy that can be differentiated from a more uniform hypokinesis observed in those with non-ischemic cardiomyopathy. Computerized ultrasonic image analysis can distinguish characteristic dyssynergic patterns in patients with cardiomyopathy. Measurements of segmental wall thickening provide a more accurate assessment of regional function.