title: Relationship between atrial function, left ventricular isovolumic relation time, and early filling in dual chamber-paced patients.
abstract: This investigation was performed to study atrial systolic function is response to modification of atrioventricular delay in a sample of 36 patients with a DDD pacemaker implanted for complete atrioventricular block. The relation between atrial systolic performance and diastolic-related parameters was also evaluated. Isovolumic relaxation time, early diastolic peak velocity, late (atrial) diastolic peak velocity, atrial filing fraction, and atrial ejection force were recorded at a pacing rate of 70 impulses/min and at atrioventricular delay of 200, 150, and 100 msec. Our data showed that the progressive shortening of atrioventricular delay induced a gradual increase in early peak velocity (median value 46 to 53 to 61.5 cm/sec, respectively, at 200, 150, and 100 msec intervals) and a gradual decrease in isovolumic relaxation time (median 92.6 to 81.5 to 69.7 msec at 200, 150, and 100 msec, respectively), atrial peak velocity (59 to 52 to 44.5 cm/sec at 200, 150, and 100 msec, respectively), atrial filling fraction (50.5% to 40% to 23.5% at 200, 150, and 100 msec, respectively), and atrial ejection force (17.2 to 14.7 to 8.5 kilodynes at 200, 150, and 100 msec, respectively). For every atrioventricular delay value detected, we found a significant correlation between isovolumic relaxation time and early peak velocity with atrial filling fraction and atrial ejection force. In addition, atrial ejection force was related directly to atrial filling fraction at studied atrioventricular delays. The two indexes of atrial systolic performance showed a parallel decrease by shortening the atrioventricular delay, and they can quantify atrial systolic performance equally in sequentially paced patients. Furthermore, our results are in accordance with the hypothesis that the interaction between the effectiveness of active left atrial emptying and isovolumetric relaxation time may play an important role in maintaining an ideal ventricular filling despite changes in atrial systolic function.
authors.affiliation: Department of Internal Medicine, University of Modena, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Rossi
authors.forename: N
authors.initials: N
authors.lastname: Muia
authors.forename: M G
authors.initials: MG
authors.lastname: Modena
mesh_terms: D000368:Aged; D016279:Atrial Function, Left; D001783:Blood Flow Velocity; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology; D009200:Myocardial Contraction; D015588:Observer Variation; D010138:Pacemaker, Artificial; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left