title: Assessment of left ventricular systolic function in patients with chronic atrial fibrillation and dilated cardiomyopathy using the ratio of preceding to prepreceding R-R intervals.
abstract: The objective of this study was to determine the relation between left ventricular (LV) systolic function and the ratio of preceding (RR1) to prepreceding (RR2) R-R intervals in patients with chronic atrial fibrillation (AF) and dilated cardiomyopathy. LV systolic function (Emax) was examined using a conductance catheter with a micromanometer in 13 patients with chronic AF and dilated cardiomyopathy. We calculated Emax as a load-independent index of LV contractility and compared it with RR1, RR2, and the ratio of RR1/RR2. We analyzed 50+/-13 cardiac cycles (range 18-61) in each patient. Average heart rate was 80+/-13 beats/min, and ejection fraction over all cardiac cycle in each patient measured by conductance catheter was 31+/-8%. Emax was positively correlated with RR1 and RR1/RR2 in all patients, and negatively correlated with RR2 in all patients. In each patient, correlation coefficients of Emax with RR1/RR2 were greater than those with either RR1 or RR2. Furthermore, Emax at RR1/RR2=1 in the linear regression line reflected average Emax over all cardiac cycles in each patient. In conclusion, we have shown that LV contractility correlated positively with RR1/RR2 in patients with chronic AF and dilated cardiomyopathy, and LV contractility at RR1/RR2=1 represents the average value of contractility over all cardiac cycles.
authors.affiliation: The First Department of Internal Medicine, Mie University School of Medicine, Tsu, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tanabe
authors.forename: Katsuya
authors.initials: K
authors.lastname: Onishi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Dohi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kitamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nobori
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakano
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000503:physiopathology*; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000503:physiopathology*; D002908:Chronic Disease; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D013599:Systole; D016277:Ventricular Function, Left