Abstract
OBJECTIVE--To investigate the nature of ventricular activation and its relation with mechanical events in patients with dilated cardiomyopathy. STUDY DESIGN--Retrospective and prospective study with 12 lead electrocardiograms, signal averaged electrocardiograms, and M mode and Doppler echocardiograms. SETTING--Tertiary cardiac referral centre. PATIENTS--77 patients (mean (SD) age 59(13)) with dilated cardiomyopathy, four after aortic valve replacement and three after coronary bypass surgery, and six patients with a normal sized left ventricle and complete right bundle branch block were studied. 15 normal subjects (age 45(20)) were used as controls. RESULTS--In patients with dilated cardiomyopathy, QRS duration was longer (127(25) ms v 90(10), P < 0.05) than normal and was normally distributed (r = 0.991, P < 0.01) on a normal probability plot. 20 had classic left bundle branch block, 29 intraventricular conduction delay, four right bundle branch block, and one bifascicular block. The PR interval was prolonged (185(30) ms v 150(15), P < 0.05). Electromechanical delay, Q to the onset of thickening of the interventricular septum as seen on the transverse M mode echocardiogram, was 75(15) ms in controls, but reduced to 43(15) ms in the patients (P < 0.01). Q to the onset of mitral regurgitation was also short (50(15)) ms, and correlated inversely with PR interval (r = -0.67, n = 73, P < 0.01). Early potentials (< 40 microV) were recorded on the signal averaged electrocardiogram in 33 representative patients and in all controls. Their overall duration was 30(12) ms in the patients, much longer than normal (12(7), P < 0.01)). Early potential time correlated positively with PR interval (r = 0.75, P < 0.01) and QRS duration (r = 0.60, P < 0.01) on a 12 lead electrocardiogram, and negatively with apparent electromechanical delay (r = -0.71, P < 0.01, n = 33), but not with true electromechanical delay (73(15)ms) or true PR interval (163(30)ms), calculated by correcting apparent values for early potential. The onset of left ventricular free wall motion was delayed with respect to the septum beyond 95% of the upper normal limit in all the patients with classic left bundle branch block and intraventricular conduction defect. Motion in the right ventricular free wall was delayed in 13 of 20 patients with left bundle branch block and 24 of 29 with intraventricular conduction defect by 65(20) ms, similar to that (75(10) ms) in patients with right bundle branch block. CONCLUSION--In most patients with dilated cardiomyopathy and an electrocardiographic pattern of left bundle branch block or intraventricular block, the onset of mechanical systole is strikingly and symmetrically delayed in both ventricles, compatible with bilateral bundle branch block. Complete atrioventricular block does not occur. The ventricle is activated through the upper septum and this activation is detectable only by signal averaged electrocardiography. The anatomical substrates for this abnormal activation could be the high connections described by Mahaim and Winston.
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Selected References
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- Brecker S. J., Xiao H. B., Sparrow J., Gibson D. G. Effects of dual-chamber pacing with short atrioventricular delay in dilated cardiomyopathy. Lancet. 1992 Nov 28;340(8831):1308–1312. doi: 10.1016/0140-6736(92)92492-x. [DOI] [PubMed] [Google Scholar]
- Brecker S. J., Xiao H. B., Stojnic B. B., Mbaissouroum M., Gibson D. G. Assessment of the peak tricuspid regurgitant velocity from the dynamics of retrograde flow. Int J Cardiol. 1992 Mar;34(3):267–271. doi: 10.1016/0167-5273(92)90023-v. [DOI] [PubMed] [Google Scholar]
- Breithardt G., Cain M. E., el-Sherif N., Flowers N. C., Hombach V., Janse M., Simson M. B., Steinbeck G. Standards for analysis of ventricular late potentials using high-resolution or signal-averaged electrocardiography. A statement by a Task Force Committee of the European Society of Cardiology, the American Heart Association, and the American College of Cardiology. Circulation. 1991 Apr;83(4):1481–1488. doi: 10.1161/01.cir.83.4.1481. [DOI] [PubMed] [Google Scholar]
- Caceres J., Jazayeri M., McKinnie J., Avitall B., Denker S. T., Tchou P., Akhtar M. Sustained bundle branch reentry as a mechanism of clinical tachycardia. Circulation. 1989 Feb;79(2):256–270. doi: 10.1161/01.cir.79.2.256. [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]
- Denereaz D., Zimmermann M., Adamec R. Significance of ventricular late potentials in non-ischaemic dilated cardiomyopathy. Eur Heart J. 1992 Jul;13(7):895–901. doi: 10.1093/oxfordjournals.eurheartj.a060289. [DOI] [PubMed] [Google Scholar]
- Ellenbogen K. A., Ramirez N. M., Packer D. L., O'Callaghan W. G., Greer G. S., Sintetos A. L., Gilbert M. R., German L. D. Accessory nodoventricular (Mahaim) fibers: a clinical review. Pacing Clin Electrophysiol. 1986 Nov;9(6 Pt 1):868–884. doi: 10.1111/j.1540-8159.1986.tb06636.x. [DOI] [PubMed] [Google Scholar]
- Flowers N. C. Left bundle branch block: a continuously evolving concept. J Am Coll Cardiol. 1987 Mar;9(3):684–697. doi: 10.1016/s0735-1097(87)80065-7. [DOI] [PubMed] [Google Scholar]
- Hollman A. The history of bundle branch block. Med Hist Suppl. 1985;(5):82–102. doi: 10.1017/s0025727300070538. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jones C. J., Raposo L., Gibson D. G. Functional importance of the long axis dynamics of the human left ventricle. Br Heart J. 1990 Apr;63(4):215–220. doi: 10.1136/hrt.63.4.215. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lau C. P., Davies D. W., Mehta D., Ward D. W., Camm A. J. Flecainide acetate in the treatment of tachycardias associated with Mahaim fibres. Eur Heart J. 1987 Aug;8(8):832–839. doi: 10.1093/oxfordjournals.eurheartj.a062346. [DOI] [PubMed] [Google Scholar]
- Luu M., Stevenson W. G., Stevenson L. W., Baron K., Walden J. Diverse mechanisms of unexpected cardiac arrest in advanced heart failure. Circulation. 1989 Dec;80(6):1675–1680. doi: 10.1161/01.cir.80.6.1675. [DOI] [PubMed] [Google Scholar]
- Mason D. T., Braunwald E., Covell J. W., Sonnenblick E. H., Ross J., Jr Assessment of cardiac contractility. The relation between the rate of pressure rise and ventricular pressure during isovolumic systole. Circulation. 1971 Jul;44(1):47–58. doi: 10.1161/01.cir.44.1.47. [DOI] [PubMed] [Google Scholar]
- Nakayama Y., Shimizu G., Hirota Y., Saito T., Kino M., Kitaura Y., Kawamura K. Functional and histopathologic correlation in patients with dilated cardiomyopathy: an integrated evaluation by multivariate analysis. J Am Coll Cardiol. 1987 Jul;10(1):186–192. doi: 10.1016/s0735-1097(87)80178-x. [DOI] [PubMed] [Google Scholar]
- Rahko P. S., Shaver J. A., Salerni R. Evaluation of mechanical events and systolic function in dilated cardiomyopathy: comparison between patients with and without left bundle branch block. Acta Cardiol. 1988;43(3):179–184. [PubMed] [Google Scholar]
- Vatterott P. J., Hammill S. C., Osborn M. J. Clinical application of the signal-averaged electrocardiogram and "late potentials". J Electrocardiol. 1989;22 (Suppl):13–18. doi: 10.1016/s0022-0736(07)80095-1. [DOI] [PubMed] [Google Scholar]
- Willems J. L., Robles de Medina E. O., Bernard R., Coumel P., Fisch C., Krikler D., Mazur N. A., Meijler F. L., Mogensen L., Moret P. Criteria for intraventricular conduction disturbances and pre-excitation. World Health Organizational/International Society and Federation for Cardiology Task Force Ad Hoc. J Am Coll Cardiol. 1985 Jun;5(6):1261–1275. doi: 10.1016/s0735-1097(85)80335-1. [DOI] [PubMed] [Google Scholar]
- Xiao H. B., Brecker S. J., Gibson D. G. Differing effects of right ventricular pacing and left bundle branch block on left ventricular function. Br Heart J. 1993 Feb;69(2):166–173. doi: 10.1136/hrt.69.2.166. [DOI] [PMC free article] [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]