Abstract
Objective—To investigate the effects of QRS duration on characteristics of the left ventricular pressure pulse derived from the time course of functional mitral regurgitation by continuous wave Doppler.
Design—Retrospective and prospective study of 50 patients with dilated cardiomyopathy, by electrocardiography, echocardiography, and Doppler cardiography.
Setting—Tertiary cardiac referral centre.
Patients—50 patients (mean age (SD) 58 (16)) with dilated cardiomyopathy, all with functional mitral regurgitation.
Results—The values of QRS duration ranged widely, from 70 to 190 ms with a mean value of 110 ms, and were unimodally distributed. The overall duration of mitral regurgitation correlated positively with QRS time (r=0·65) over the entire range of values. When the duration of mitral regurgitation was divided into contraction, aortic ejection, and relaxation times, increased QRS duration prolonged contraction (r=0·51) and relaxation (r=0·52) times. Aortic ejection time was affected by RR interval (r=0·74). Duration of QRS correlated negatively with peak rate of rise in left ventricular pressure (+dP/dt) (r=−0·48), and positively with the time intervals from Q to peak pressure (r=0·49) and to peak +dP/dt (r=0·72), and also with those from the start of mitral regurgitation to peak pressure (r=0·49) and to peak +dP/dt (r=0·76). Duration of QRS did not directly affect the peak rate of left ventricular pressure fall (−dP/dt), or the isovolumic relaxation period.
Conclusions—Values of QRS duration are unimodally distributed in patients with dilated cardiomyopathy, without evidence of a discrete group of patients with left bundle branch block. Prolonged QRS duration reduces peak +dP/dt, prolongs overall duration of the pressure pulse, the time to peak +dP/dt, and relaxation time. Duration of QRS must therefore be taken into account in assessing standard measurements of myocardial function in patients with dilated cardiomyopathy.
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bargiggia G. S., Bertucci C., Recusani F., Raisaro A., de Servi S., Valdes-Cruz L. M., Sahn D. J., Tronconi L. A new method for estimating left ventricular dP/dt by continuous wave Doppler-echocardiography. Validation studies at cardiac catheterization. Circulation. 1989 Nov;80(5):1287–1292. doi: 10.1161/01.cir.80.5.1287. [DOI] [PubMed] [Google Scholar]
- Chen C., Rodriguez L., Guerrero J. L., Marshall S., Levine R. A., Weyman A. E., Thomas J. D. Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography. Circulation. 1991 Jun;83(6):2101–2110. doi: 10.1161/01.cir.83.6.2101. [DOI] [PubMed] [Google Scholar]
- Ng K. S., Gibson D. G. Impairment of diastolic function by shortened filling period in severe left ventricular disease. Br Heart J. 1989 Oct;62(4):246–252. doi: 10.1136/hrt.62.4.246. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nikolic S., Yellin E. L., Tamura K., Tamura T., Frater R. W. Effect of early diastolic loading on myocardial relaxation in the intact canine left ventricle. Circ Res. 1990 May;66(5):1217–1226. doi: 10.1161/01.res.66.5.1217. [DOI] [PubMed] [Google Scholar]
- Ross J., Jr Cardiac function and myocardial contractility: a perspective. J Am Coll Cardiol. 1983 Jan;1(1):52–62. doi: 10.1016/s0735-1097(83)80010-2. [DOI] [PubMed] [Google Scholar]
- Xiao H. B., Lee C. H., Gibson D. G. Effect of left bundle branch block on diastolic function in dilated cardiomyopathy. Br Heart J. 1991 Dec;66(6):443–447. doi: 10.1136/hrt.66.6.443. [DOI] [PMC free article] [PubMed] [Google Scholar]