quinta-feira, junho 17, 2010
Congresso Mundial : Edema pulmonar
The Role of Cardiac Dyssynchrony in the Pathogenesis of Acute
Hypertensive Pulmonary Edema
Andrei-Dumitru Margulescu1,, Roxana Cristina Sisu1,2, Maria Florescu2, Mircea
Cinteza1,2, Dragos Vinereanu
Introduction: The role of acute cardiac dyssynchrony during acute hypertensive pulmonary edema (AHPE) has not been evaluated. Methods: 51 consecutive patients (69 11 years, 31 women), admitted to an intensive cardiac care unit with the diagnosis of AHPE, were evaluated by conventional and tissue Doppler echocardiography, during the acute episode, and again at 48 to 92 hours. Inclusion criteria were: acute respiratory distress within the preceding 8 hours with clinical and radiological pulmonary congestion, systolic BP 160 mmHg, and sinus rhythm; patients with acute myocardial infarction or moderate and severe left-sided valvar diseases were excluded. Inter-ventricular dyssynchrony was assessed from aorto-pulmonary
flow delay (APD), and maximal difference between peak-to-peak myocardial velocity tracings of any LV segment and the RV segment (Inter). Intra-ventricular dyssynchrony was assessed from maximal delay of peak-to-peak systolic myocardial velocities (MxS) and peak systolic displacement (MxD) in 6 basal segments of opposing LV walls, standard deviation of time-to-peak myocardial systolic velocity in 12 myocardial segments (Yu index), and aortic pre-ejection time (APT). Atrio-ventricular (AV) synchrony was assessed from diastolic filling time (% of the cardiac cycle,%DFT). Severity and mechanisms of secondary mitral regurgitation (MR) were assessed using qualitative (visual grading by a scale from 1 to 4), and quantitative
measurements (vena contracta, MR area, tenting area of the mitral valve, and diameter of the mitral annulus).
Results: Complete left bundle branch block (LBBB) was present in 12 patients during ACPE and in 13 at follow-up (p 0.5). Inter-ventricular (APD: 26 vs. 25 ms, p 0.88; Inter: 45 vs. 54 ms; p 0.36) and intra-ventricular dyssynchrony indexes (MxS: 42 vs. 61 ms,p 0.12; MxD: 28 vs. 29 ms, p 0.44; Yu index: 35 vs. 37 ms, p 0.63; APT: 90 vs. 89 ms, p 0.82) showed that AHPE was not associated with acute dyssynchrony, after adjustment for differences in heart rate (94 vs. 75 bpm, p 0.001).%DFT was reduced during AHPE compared with follow-up (40% vs. 48%, p 0.001), suggesting impaired AV synchrony induced by the increased HR. Duration of the A wave did not differ between evaluations (138 ms vs. 140 ms, p 0.7). The severity of MR was similar between evaluations.
Conclusion: Impaired atrio-ventricular synchrony, but not acute inter- and intra- ventricular dyssynchrony are involved in the pathogenesis of AHPE.