Abstract

MIGLIORE, Ricardo A. et al. Effects of Changes in Atrioventricular Delay on dP/dt in Patients with Dilated Cardiomyopathy. Rev. argent. cardiol. [online]. 2006, vol.74, n.5, pp.276-280. ISSN 1850-3748.

Background Left ventricular LV dP/dt is an index used to assess ventricular function and prognosis in dilated cardiomyopathy, but it is preload and afterload-dependent. Changes in the coupling interval between atrial and ventricular contraction may influence ventricular end-diastolic load (preload) and hence modify the dP/dt. Objective To analyze the effects of changes in atrioventricular (AV) delay on dP/dt in patients with dilated cardiomyopathy. Material and Methods Twelve patients (6 men and 6 women; mean age: 51±13 years), with dilated cardiomyopathy, programmable dualchamber pacemakers and mitral regurgitation were studied. The dP/dt was assessed with Bargiggia's method. In all patients, the AV delay was modified within the maximum and minimum possible values, at 50 msec decrements (3 to 6 AV delays per patient) without any change in heart rate. Thus, for different AV delays, a wide range of dP/dt values were obtained. For correlation analysis, dP/dt values and AV delays were expressed as the percent change (% D) from the minimum dP/dt value and the maximum AV delay. Results The minimum dP/dt was 491 ± 114 mmHg/sec with an AV delay of 246 ± 70 msec, and the maximum dP/dt was 729± 98 mmHg/sec with an AV delay of 75 ± 34 msec (p<0.0001). Decreases in AV delay correlated with an increase in dP/dt: r = -0.74, y = 0.59 -28.x (p<0.001). Conclusion In patients with dilated cardiomyopathy, dP/dt is sensitive to changes in AV delay, thus demonstrating its preload-dependence. This finding should be taken into account when measuring dP/dt to assess systolic function and prognosis in dilated cardiomyopathy.

Keywords : Echocardiography; Ventricular function; Pacemaker, artificial.