Heterogeneous Fate of Perfusion and Contraction After Anterior Wall Acute Myocardial Infarction and Effects on Left Ventricular Remodeling Claudio Marcassa, MD, Michele Galli, MD, Roberto Bolli, MD, PierLuigi Temporelli, MD, Riccardo Campini, MD, and Pantaleo Giannuzzi, MD After acute myocardial infarction, patency of infarct ves- sel and extent of left venticular (LV) dysfunction are major determinants of ventricular remodeling. Sponta- neous, delayed reperfusion in the infarct zone occurs in a sizeable number of patients well after the subacute phase. The aim of this study was to determine the rela- tion between the occurrence of this spontaneous, de- layed reperfusion and LV remodeling. In 84 patients, resting LV volumes, topography, regional function, and perfusion were quantitatively evaluated by 2-dimen- sional echocardiography and sestamibi tomography 5 weeks (study 1) and 7 months (study 2) after anterior Q-wave infarction. At study 2, LV end-diastolic volume increased by >15% in 17 patients (20%, LV remodel- ing); they had already had at study 1 significantly larger LV volumes, more severe hypoperfusion and wall mo- tion abnormalities, and greater regional dilation than patients with stable LV volumes. Delayed reperfusion occurred in 8 of 17 patients with and in 42 of 67 patients without LV remodeling (47% vs 63%; p  NS). At study 2, LV regional dilation and end-diastolic volumes were stable in patients with, but increased in patients without, spontaneous reperfusion (from 25  24% to 29  26% at study 2 [p<0.05] and from 65  14 to 68  18 ml/m 2 [p <0.05]). At multivariate analysis, however, regional ventricular dilation at study 1 was the sole predictor of further LV remodeling. Thus, after acute myocardial infarction, spontaneous reperfusion occur- ring after 5 weeks plays only a minor role in influencing LV remodeling. Benefits from delayed reperfusion seem limited to patients with preserved LV volumes; patients with an enlarged left ventricle 5 weeks after acute in- farction are prone to further LV remodeling, irrespective of delayed reperfusion. 1998 by Excerpta Medica, Inc. (Am J Cardiol 1998;82:1457–1462) P rogressive left ventricular (LV) dilation is fre- quently observed during the convalescent period after acute myocardial infarction (MI). 1,2 The expan- sion of the infarcted segment in the early phase is followed by dilation of the entire left ventricle due to lengthening of both infarcted and noninfarcted seg- ments (ventricular “remodeling”). 3 Coronary artery reperfusion has been shown to exert a beneficial effect on LV remodeling. 4,5 Recent studies indicate that the interval after coronary occlusion at which reperfusion is of benefit in reducing subsequent LV dilation seems substantially longer than previously thought. 6–8 Even a late increase in flow through the infarct-related ar- tery can restore myocardial function in chronically ischemic, noncontracting but viable myocardium. 9 We recently documented that a spontaneous recovery of perfusion and contraction in the infarcted area may continue well after the subacute phase in a sizeable number of patients with anterior infarction. 10 These findings have been confirmed by other investiga- tors. 11,12 The aim of the present study was to deter- mine whether this spontaneous delayed reperfusion in the infarct zone has a favorable influence on the re- modeling response. METHODS Study cohort: We evaluated 125 consecutive male patients with recent anterior MI, who were enrolled from January 1990 to February 1992 in a prospective trial. 12 All patients met the following inclusion crite- ria: (1) history of recent (4 to 6 weeks) first Q-wave anterior MI; (2) sinus rhythm and no conduction dis- turbances; (3) no angina at rest; and (4) New York Heart Association functional class I or II. The diag- nosis of acute MI was supported by a typical history of chest pain (30 minutes), evolving ST-segment ele- vation and abnormal Q waves in at least 2 adjacent precordial leads and in leads I and/or aVL, and a typical pattern of serum myocardial enzymes. Exclu- sion criteria were severe LV dysfunction (ejection fraction 25%) and residual angina uncontrolled with medical therapy. Study protocol: Resting LV regional myocardial perfusion and function were evaluated on the same day with sestamibi tomography and 2-dimensional echocardiography, respectively. The scintigraphic and echocardiographic studies were performed in all pa- tients 5 weeks after acute infarction (study 1) and then repeated at 7 months (study 2). All patients were clinically stable between the 2 studies. Sixty-five pa- From the Cardiology Division and Nuclear Medicine Laboratory, Salvatore Maugeri Foundation IRCCS, Medical Institute of Rehabilita- tion of Veruno, Italy; and Division of Cardiology, University of Louis- ville, Louisville, Kentucky. This study was supported in part by the Grant Ricerca Corrente 1996/97, from the Ministero della Sanita', Rome, Italy. Manuscript received May 5, 1998; revised manuscript received and accepted July 15, 1998. Address for reprints: Claudio Marcassa, MD, Salvatore Maugeri Foundation, IRCCS, Cardiology Division, via Per Revislate 13, Veruno 28010 (No) Italy. E-mail: cdl@intercom.it 1457 ©1998 by Excerpta Medica, Inc. 0002-9149/98/$19.00 All rights reserved. PII S0002-9149(98)00687-0