Relation between regional electrical activation time and subepicardial fiber strain in the canine left ventricle
- PMID: 8488095
- DOI: 10.1007/BF00374964
Relation between regional electrical activation time and subepicardial fiber strain in the canine left ventricle
Abstract
To determine the relation between regional electrical activation time and fiber strain, epicardial electrical activation and deformation were measured in six open-chest dogs at the left ventricular anterior free wall after 15 min of right atrial, left ventricular free wall, left ventricular apex, or right ventricular outflow tract pacing, when end-diastolic pressure was normal or elevated (volume-loading). Regional electrical activation was measured using a 192-electrode brush. Regional subepicardial fiber strain (ef) was measured simultaneously in 16 regions, using optical markers which were attached to the epicardial surface and recorded on video. When relating regional ef during the ejection phase to regional activation time, the best correlation was found when a hemodynamic time reference rather than an electrophysiological one is used. Using the moment of the maximum rate of change of left ventricular pressure as the time reference for electrical activation, regional electrical activation time (t(ea)) and the degree of ef during the ejection phase could be fitted by a linear regression equation ef = a t(ea) + b, in which a = -3.46 +/- 0.73 s-1 an b = -0.28 +/- 0.05. For electrical activation times ranging from -40 to -80 ms, fiber strain was estimated with an accuracy of +/- 0.026 (+/- SE) with this relation. During right atrial pacing, t(ea) and ef were on the average -48 ms and -0.10 respectively. On further investigation, the relation between ef and t(ea) appeared to be influenced by end-diastolic pressure. For normal (1.1 kPa) and elevated end-diastolic pressure (1.8 kPa), the slope of the linear regression line was -3.96 and -2.86 s-1, respectively. Three conclusions may be drawn. Firstly, the time interval between the moment of regional electrical activation and the moment of the maximum rate of change of left ventricular pressure is an index of regional fiber strain. Secondly, it can be concluded from the above equations that electrical asynchrony of more than 30 ms causes non-uniformities in the degree of ef of the order of mean ef during pacing from the right atrium. Finally, differences in fiber strain during asynchronous electrical activation are less pronounced at larger filling pressures.
Similar articles
-
Regional fibre stress-fibre strain area as an estimate of regional blood flow and oxygen demand in the canine heart.J Physiol. 1994 Jun 15;477 ( Pt 3)(Pt 3):481-96. doi: 10.1113/jphysiol.1994.sp020209. J Physiol. 1994. PMID: 7932236 Free PMC article.
-
Regional electrical activation and mechanical function in the partially ischemic left ventricle of dogs.Am J Physiol. 1996 Dec;271(6 Pt 2):H2411-20. doi: 10.1152/ajpheart.1996.271.6.H2411. Am J Physiol. 1996. PMID: 8997300
-
Redistribution of myocardial fiber strain and blood flow by asynchronous activation.Am J Physiol. 1990 Aug;259(2 Pt 2):H300-8. doi: 10.1152/ajpheart.1990.259.2.H300. Am J Physiol. 1990. PMID: 2386214
-
Relation between the pacing induced sequence of activation and left ventricular pump function in animals.Pacing Clin Electrophysiol. 2002 Apr;25(4 Pt 1):484-98. doi: 10.1046/j.1460-9592.2002.00484.x. Pacing Clin Electrophysiol. 2002. PMID: 11991375 Review.
-
Estimates of regional work in the canine left ventricle.Prog Biophys Mol Biol. 1998;69(2-3):273-87. doi: 10.1016/s0079-6107(98)00012-1. Prog Biophys Mol Biol. 1998. PMID: 9785943 Review.
Cited by
-
Redistribution of myocardial perfusion during permanent dual chamber pacing in symptomatic non-obstructive hypertrophic cardiomyopathy: a quantitative positron emission tomography study.Heart. 1996 May;75(5):522-4. doi: 10.1136/hrt.75.5.522. Heart. 1996. PMID: 8665349 Free PMC article.
-
Simultaneous optical mapping of transmembrane potential and wall motion in isolated, perfused whole hearts.J Biomed Opt. 2011 Sep;16(9):096020. doi: 10.1117/1.3630115. J Biomed Opt. 2011. PMID: 21950934 Free PMC article.
-
Regional fibre stress-fibre strain area as an estimate of regional blood flow and oxygen demand in the canine heart.J Physiol. 1994 Jun 15;477 ( Pt 3)(Pt 3):481-96. doi: 10.1113/jphysiol.1994.sp020209. J Physiol. 1994. PMID: 7932236 Free PMC article.
-
Biomechanics of cardiac electromechanical coupling and mechanoelectric feedback.J Biomech Eng. 2014 Feb;136(2):021007. doi: 10.1115/1.4026221. J Biomech Eng. 2014. PMID: 24337452 Free PMC article. Review.
-
Effects of permanent dual chamber pacing on myocardial perfusion in symptomatic hypertrophic cardiomyopathy.Heart. 1996 Oct;76(4):358-62. doi: 10.1136/hrt.76.4.358. Heart. 1996. PMID: 8983685 Free PMC article.
References
Publication types
MeSH terms
LinkOut - more resources
Miscellaneous