Left ventricular remodeling in the year after first anterior myocardial infarction: A quantitative analysis of contractile segment lengths and ventricular shape

Gary F. Mitchell*, Gervasio A. Lamas, Douglas E. Vaughan, Marc A. Pfeffer

*Corresponding author for this work

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251 Scopus citations

Abstract

Infarct expansion after myocardial infarction results in early ventricular enlargement and distortion of ventricular geometry. To characterize the components of late volume enlargement, biplane left ventriculography was performed in 52 patients 3 weeks and 1 year after a first anterior myocardial infarction. Biplane diastolic circumference and contractile and noncontractile segment lengths were measured. Global geometry was evaluated by using a sphericity index (angiographic volume of the ventricle divided by the volume of a sphere with the same circumference). Regional geometry was assessed by measurement of endocardial curvature, an important determinant of wall tension. End-diastolic volume was enlarged at baseline and increased at 1 year (230 ± 42 to 244 ± 55 ml, p = 0.01) as a result of increases in contractile segment length (34 ± 5 to 37 ± 5 cm, p < 0.001) and sphericity index (0.74 ± 0.07 to 0.76 ± 0.08, p < 0.001), whereas the noncontractile segment length decreased (15 ± 6 to 12 ± 6 cm, p < 0.005). Curvature analysis revealed a flattening of presumably high tension concavity at the anterobasal (-6.0 ± 4.0 to -4.5 ± 3.7, p < 0.01) and inferior (-4.5 ± 2.0 to -3.6 ± 2.1, p < 0.005) margins of the infarct and less bulging of the anterior wall (9.4 ± 2.5 to 8.2 ± 2.3, p < 0.001). Patients selected for late enlargement (diastolic volume increase >20 ml, n = 19) had an increase in sphericity (0.75 ± 0.05 to 0.80 ± 0.08, p < 0.005) and in diastolic circumference (54 ± 3 to 56 ± 4 cm, p < 0.001) secondary to elongation of the contractile segment (32 ± 4 to 36 ±4 cm, p = 0.001) at 1 year. Thus, late ventricular enlargement after anterior infarction results from an increase in contractile segment length and a change in ventricular geometry and is not a result of progressive infarct expansion. In the group of patients at high risk for late ventricular enlargement because of persistent occlusion of the infarct-related vessel, captopril therapy attenuated late volume enlargement by preventing these changes in contractile segment length and chamber geometry.

Original languageEnglish (US)
Pages (from-to)1136-1144
Number of pages9
JournalJournal of the American College of Cardiology
Volume19
Issue number6
DOIs
StatePublished - May 1992

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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