Combined exercise radionuclide and hemodynamic evaluation of left ventricular aneurysmectomy

Acute decrease of left ventricular mechanical dyssynchrony and improvement of contractile state and energy efficiency after left ventricular restoration

OBJECTIVE

Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency.

METHODS

Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a conductance volume catheter to analyze pressure-volume relationships, energy efficiency, and mechanical dyssynchrony. The end-systolic elastance was used as a load-independent index of contractile state. Left ventricular energy efficiency was calculated from stroke work and total pressure-volume area. Segmental volume changes perpendicular to the long axis were used to calculate mechanical dyssynchrony. Statistical analysis was performed with the paired t test and least-squares linear regression.

RESULTS

Endoventricular patch aneurysmectomy reduced end-diastolic volume by 37% (P < .001), with unchanged stroke volume. Systolic function improved, as derived from increased +dP/dt(max), by 42% (P < .03), peak ejection rate by 28% (P < .02), and ejection fraction by 16% (P < .0002). Early diastolic function improved, as shown by reduction of -dP/dt(max) by 34% (P < .006) and shortened tau by 30% (P < .001). Left ventricular end-systolic elastance increased from 1.2 +/- 0.6 to 2.2 +/- 1 mm Hg/mL (P < .001). Left ventricular energy efficiency increased by 36% (P < .002). Left ventricular mechanical dyssynchrony decreased during systole by 33% (P < .001) and during diastole by 20% (P < .005).

CONCLUSIONS

Left ventricular restoration induced acute improvements in contractile state, energy efficiency, and relaxation, together with a decrease in left ventricular mechanical dyssynchrony.

Local myocardial overexpression of growth hormone attenuates postinfarction remodeling and preserves cardiac function

BACKGROUND

Ventricular remodeling with chamber dilation and wall thinning is seen in postinfarction heart failure. Growth hormone induces myocardial hypertrophy when oversecreted. We hypothesized that localized myocardial hypertrophy induced by gene transfer of growth hormone could inhibit remodeling and preserve cardiac function after myocardial infarction.

METHODS

Rats underwent direct intramyocardial injection of adenovirus encoding either human growth hormone (n = 9) or empty null vector as control (n = 9) 3 weeks after ligation of the left anterior descending coronary artery. Analysis of the following was performed 3 weeks after delivery: hemodynamics, ventricular geometry, cardiomyocyte fiber size, and serum growth hormone levels.

RESULTS

The growth hormone group had significantly better systolic cardiac function as measured by maximum left ventricular pressure (73.6 +/- 6.9 mm Hg versus control 63.7 +/- 7.8 mm Hg, p < 0.05) and maximum dP/dt (2845 +/- 453 mm Hg/s versus 1949 +/- 605 mm Hg/s, p < 0.005), and diastolic function as measured by minimum dP/dt (-2520 +/- 402 mm Hg/s versus -1500 +/- 774 mm Hg/s, p < 0.01). Ventricular geometry was preserved in the growth hormone group (ventricular diameter 12.2 +/- 0.7 mm versus control 13.1 +/- 0.4 mm, p < 0.05; borderzone wall thickness 2.0 +/- 0.2 mm versus 1.5 +/- 0.1 mm, p < 0.001), and was associated with cardiomyocyte hypertrophy (6.09 +/- 0.63 microm versus 4.66 +/- 0.55 microm, p < 0.005). Local myocardial expression of growth hormone was confirmed, whereas serum levels were undetectable after 3 weeks.

CONCLUSIONS

Local myocardial overexpression of growth hormone after myocardial infarction resulted in cardiomyocyte hypertrophy, attenuated ventricular remodeling, and improved systolic and diastolic cardiac function. The induction of localized myocardial hypertrophy presents a novel therapeutic approach for the treatment of ischemic heart failure.

Radio frequency heating of chronic ovine infarct leads to sustained infarct area and ventricular volume reduction

OBJECTIVE

Myocardial infarct expansion and subsequent left ventricular remodeling are associated with increased incidence of congestive failure and mortality. Collagen is known to denature and contract when heated above 65 degrees C. We therefore tested the hypothesis that radio frequency heating of myocardial infarct tissue with application of a restraining patch causes a sustained reduction in myocardial infarct area and left ventricular volume.

METHODS

Thirteen male Dorset sheep underwent surgical coronary artery ligation. At least 14 weeks later, animals were randomized to either radio frequency infarct heating (95 degrees C) with application of a restraining patch or a sham operation. Before treatment, after treatment, and 10 weeks later, left ventricular volume was measured with transdiaphragmatic echocardiography and myocardial infarct area was measured with an array of sonomicrometry crystals.

RESULTS

Radio frequency infarct heating causes an acute decrease of 34% (-215 +/- 82 mm(2); P =.0002) in infarct area at end-diastole that is maintained at 10 weeks (-144 +/- 79 mm(2); P =.0002). Radio frequency infarct heating causes a downward trend in end-diastolic left ventricular volume measured by echocardiography of 20% (-15.7 +/- 6.3 mL; P = no significant difference) and end-systolic left ventricular volume of 32% (-17.1 +/- 9.8 mL; P =.09), which are significantly decreased at 10 weeks (-13.6 +/- 22.3 mL; P =.007 and -15.3 +/- 21.9 mL; P =.008, respectively). Radio frequency infarct heating causes an acute improvement in systolic function (P <.001), a sustained increase in left ventricular ejection fraction (+0.11%; P =.06), and preserved stroke volume.

CONCLUSION

Radio frequency heating of chronic left ventricular myocardial infarct causes a sustained reduction in infarct area and left ventricular volume. This technique may beneficially reverse infarct expansion and left ventricular remodeling after myocardial infarction.

Ventricular volume, chamber stiffness, and function after anteroapical aneurysm plication in the sheep

OBJECTIVE

The success of left ventricular aneurysm plication depends on how the procedure affects both end-systolic elastance and diastolic compliance and how those changes affect ventricular function (stroke work/end-diastolic volume [PRSW] and stroke volume/end-diastolic pressure [Starling] relationships).

METHODS

Five male Dorsett sheep were surgically instrumented with coronary artery snares, an inferior vena caval occluder, and an ascending aortic ultrasonic flow probe. One week later an anteroapical myocardial infarction was produced by tightening the coronary snares. Ten weeks after myocardial infarction, the left ventricular aneurysm was plicated. Absolute left ventricular volume was measured by long-axis transdiaphragmatic echocardiography, and relative changes in left ventricular volume were measured with a conductance catheter. End-systolic elastance, diastolic compliance, PRSW, and Starling relationships were measured immediately before myocardial infarction, 10 weeks after myocardial infarction (immediately before plication), and immediately after and 6 weeks after aneurysm plication.

RESULTS

After plication, end-diastolic and end-systolic left ventricular volumes return to preinfarction values. The slopes of end-systolic elastance, diastolic compliance, and PRSW decrease 10 weeks after myocardial infarction, increase with aneurysm plication, and then decrease 6 weeks after aneurysm plication. The Starling relationship undergoes a downward parallel shift with aneurysm plication.

CONCLUSION

Aneurysm plication abruptly decreases left ventricular volume and diastolic compliance, increases end-systolic elastance and PRSW, but decreases the Starling relationship. The net effect on left ventricular function is mixed. Furthermore, left ventricular remodeling 6 weeks after aneurysm plication causes left ventricular volume, end-systolic elastance, diastolic compliance, PRSW, and the Starling relationship to return to preplication values.

Effect of aneurysmectomy on left ventricular shape and function: case studies

The three dimensional (3D) conformational changes in three patients with large anterior aneurysm in the left ventricle (LV) were examined before and two years after aneurysmectomy by using 3D Cine-computerized tomography (CT). Endocardial and epicardial tracings of 6-9 short axis images encompassing the entire LV were used to reconstruct the LV in 3D. Thickness and percent thickening were calculated using our 3D-volume element approach. A regional wall stress index (stress/pressure) was calculated from regional curvature and thickness. The analysis showed that following resection of the aneurysm the end-diastolic volume was reduced from 257+/-39 to 183+/-39 ml, end-systolic volume from 172+/-39 to 92+/-46 ml and, ejection fraction increased from 34+/-7 to 51+/-13%. The endocardial aneurysm area decreased from 19.7+/-15.9 to 10.1+/-6.5 cm2, whereas the normal zone area was minimally reduced from 87.4+/-17.6 to 79.8+/-10.8 cm2. The percent thickening of the normal zone increased significantly. It is documented here for the first time by detailed 3D analysis that the resection of the LV aneurysm reduces the aneurysmal area and LV size and improves the global and regional function of the remote normal zone. Therefore, the 3D approach can help to design better surgical technique for this complex operation.

Comparison of tomographic and planar radionuclide ventriculography in the assessment of regional left ventricular function in patients with left ventricular aneurysm before and after surgery

METHODS AND RESULTS

To compare tomographic and planar radionuclide ventriculography (RNVG) in assessing regional left ventricular (LV) function and predicting improvement in LV ejection fraction (LVEF) after operation in patients with LV aneurysm, 18 patients with aneurysm underwent both tomography and planar RNVG 1 month before and 3 weeks to 6 months after aneurysmectomy and coronary artery bypass grafting. All patients also underwent preoperative contrast angiography at catheterization. The percent shortening of the apical, anterior, lateral, inferior, and basal segments was calculated from tomographic long-axis and short-axis slices and corresponding planar images (anterior and 30- and 70-degree left anterior oblique views). No significant differences in anterior, apical, and lateral percent shortening were apparent before aneurysmectomy between tomographic and planar studies. However, preoperative basal percent shortening was 47% +/- 13% from tomographic and 28% +/- 14% from planar images (p < 0.001). Preoperative tomography generally agreed better with contrast angiographic results than did planar imaging. After aneurysmectomy, basal function improved to 57% +/- 12% (p < 0.01) by tomography. For all patients, LVEF increased from 29% +/- 8% before to 38% +/- 9% (p < 0.01) after aneurysmectomy. However, the greatest improvement (31% +/- 11% to 41% +/- 9%; p < 0.01) was in the 15 patients with greater than 30% basal shortening by tomography before aneurysmectomy; in contrast, no change of LVEF occurred in the three patients with lesser preoperative basal percent shortening. Moreover, greater than 30% basal percent shortening by tomography before aneurysmectomy identified the group most likely to have an increase in LVEF of 5% or more from before to after aneurysmectomy. Prediction of postoperative results was not possible from preoperative planar data. Thus in patients with LV aneurysm, tomographic RNVG appears to provide information that is different and more accurately predictive of results after aneurysmectomy than that available from planar imaging.

Linear left ventricular aneurysmectomy: modern imaging studies reveal improved morphology and function

It remains uncertain whether left ventricular aneurysmectomy (LVA) improves ventricular function and whether LVA improves or distorts left ventricular contour. We applied the powerful imaging techniques of multiple-gated acquisition scanning, intraoperative transesophageal echocardiography, and magnetic resonance imaging to assess functional and morphologic changes after LVA in 75 consecutive patients undergoing LVA by conventional resection and linear closure. Fifty-two patients (69%) underwent concomitant coronary artery bypass grafting, 25 (33%) had directed endocardial resection, and 4 (5%) had valve replacement. The hospital mortality rate was 6.7% (5/75). Actuarial survival rates were 86%, 80%, and 64% at 1 year, 2 years, and 5 years, respectively. Mean anginal class improved from 3.49 to 1.24 (p < 0.0001). Mean congestive heart failure class improved from 3.04 to 1.70 (p < 0.0001). By multiple-gated acquisition scan (48 patients), mean ejection fraction improved from 0.25 preoperatively to 0.33 postoperatively (p < 0.0001). Intraoperative transesophageal echocardiography (28 patients) revealed no cases of distortion and demonstrated normalization of left ventricular contour in 69% of patients. Mean wall motion score improved from 16.4 to 18.8 (p < 0.001). Mean cross-sectional area of the left ventricle decreased from 18.7 cm2 to 12.8 cm2 (p < 0.006). Magnetic resonance imaging confirmed normalization of left ventricular contour without distortion. We conclude that linear LVA is clinically effective and objectively improves left ventricular morphology and function. On this basis, we have extended application of LVA to include patients with at least moderate-sized aneurysms undergoing coronary artery bypass grafting, despite the absence of traditional indications of arrhythmia, embolism, and frank congestive heart failure.

Functional results of left ventricular reconstruction

From 1988 to 1991, 48 patients with left ventricular aneurysm underwent endoventriculoplasty with a circular patch to preserve the left ventricular geometry. Of these patients, 98% underwent concomitant myocardial revascularization, and in 77% the left anterior descending coronary artery was bypassed. The overall operative mortality rate was 4.1%. The 3-year survival rate was 91%, and 67% of patients had no further cardiac complications. Cardiac performance was assessed postoperatively by ventriculography in 28 patients. The global ejection fraction rose from 0.39 +/- 0.11 to 0.57 +/- 0.14 (p < 0.001); the left ventricular end-diastolic pressure fell from 20 +/- 7.5 mm Hg to 15 +/- 7.8 mm Hg (p < 0.05). Computerized analysis of regional contraction revealed a significant improvement in the anterolateral and apical segments and in the transitional zone. In 61% of the patients, a normal contraction pattern resumed, whereas in the remaining 39%, a residual deformity of the left ventricular chamber was present. The best results were obtained in patients with a preserved proximal septum at echocardiography.

Surgery for chronic left ventricular aneurysm. Benefits and side effects

Seventy patients who underwent elective resection of symptomatic postinfarction apico-anterior left ventricular (LV) aneurysm with or without coronary revascularization are reviewed. The early (< or = 30 day) mortality was 5.7%. Mural thrombosis occurred in 29 cases (41.4%), unrelated to the degree of preoperative LV impairment and predictable from preoperative LV angiography in only seven cases. The response to surgery comprised significant overall improvement of global LV ejection fraction (LVEF) during rest and of all variables in stress testing. This LVEF recovery correlated significantly with that of peak ejections rate, a variable of myocardial contractility. Contrastingly, right ventricular ejection fraction (RVEF) at rest decreased slightly but significantly without correlation to preoperative RVEF or LVEF. In comparisons between patients with congestive heart failure or angina at rest as dominant symptom, the former group showed greater depression of preoperative watt and LVEF but better postoperative recovery of these variables, while right ventricular deterioration was significant only in the latter. Postoperative recovery was best in patients with poor preoperative LV function (LVEF < or = 20%), even when surgery comprised only aneurysmectomy in isolated but ungraftable LAD disease (5 cases). The observed RV deterioration may be 'nonspecific', but it must be kept in mind as a side effect of the operation, as it detracts unpredictably from postoperative ventricular recovery. Patients with well preserved preoperative LVEF, small LV aneurysm and marginal expected post-aneurysmectomy changes according to LaPlace's law are probably at risk, and surgery should then instead be directed towards preserving the remaining viable myocardium by direct revascularization.

Late results of operation for ventricular tachycardia

We have analyzed results in 54 consecutive patients with recurrent ventricular tachycardia and coronary artery disease in whom we used an aggressive surgical approach involving map-directed ventricular tachycardia ablation, scar excision and left ventricular remodeling, and coronary artery bypass grafting, as well as staged mitral valve replacement when necessary. We have previously shown age greater than 65 years to be an independent predictor of mortality and have excluded such patients from this series. Average age was 56 +/- 7 years. All patients had a previous myocardial infarction; 24% of the infarctions (13/54) were posterior in location. Symptoms included syncope or presyncope in 83% of the patients (45/54), angina in 54% (29/54), and congestive heart failure in 52% (28/54). Extensive coronary artery disease was found in 78% (42/54), and 89% (48/54) had serious compromise of left ventricular function (ejection fraction < 0.40; average ejection fraction, 0.28 +/- 0.12). Only 63% (34/54) appeared to have a resectable left ventricular aneurysm on the preoperative angiogram. Ablation techniques included endocardial excision in 82% (44/54), with the addition of cryoablation in 60% (32/54), and balloon electric shock ablation in 22% (12/54); coronary artery bypass grafting was performed in 85% (46/54). There were four hospital deaths (7%). The surgical cure rate (no inducible VT at postoperative electrophysiologic study was 72% (39/54). During follow-up (mean, 50 +/- 31 months) there have been six late deaths (1 sudden death, 1 stroke, 4 congestive heart failures with or without mitral regurgitation). Four patients with progressive congestive heart failure and serious mitral regurgitation have undergone repeat operation for mitral valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Early hemodynamic results of left ventricular reconstructive surgery for anterior wall left ventricular aneurysm

To assess the efficacy of left ventricular (LV) reconstruction after aneurysmectomy, 35 consecutive patients with anterior LV aneurysm were studied before and after surgery. Surgical technique was performed by applying a circular patch after aneurysmectomy to maintain a "more physiological" LV cavity. Myocardial revascularization was performed in all but 1 patient concurrently. Global perioperative mortality was 4.8%. LV filling pressure and volumes and regional wall motion were assessed before and after surgery. The major indication for surgery was angina; 8 patients were in New York Heart Association class III/IV. The results showed a significant decrease in end-diastolic volume index (from 120 +/- 55 ml/m2 to 76 +/- 22 ml/m2, p less than 0.001), end-systolic volume index (from 74 +/- 44 ml/m2 to 40 +/- 18 ml/m2, p less than 0.001) and end-diastolic pressure (from 17 +/- 7 mm Hg to 13 +/- 5 mm Hg, p less than 0.05). Ejection fraction significantly increased (from 39 +/- 13% to 49 +/- 15%, p less than 0.001). LV wall motion significantly improved in all but the anterobasal region; the extent of LV asynergy significantly decreased after surgery. Six of the 35 patients had a deterioration of postintervention ejection fraction (from 44 +/- 14% to 34 +/- 9%). They had no reduction in LV volumes and no improvement in wall kinetics. It is concluded that LV reconstruction after aneurysmectomy induces significant early improvement of global and regional LV function in most patients; postoperative functional improvement is mainly related to the increase in inferior LV wall motion.

Left ventricular aneurysmectomy in patients with poor left ventricular function

Physical performance and left ventricular (LV) function in the resting state were assessed in 22 patients with postinfarction anterior-apical left ventricular aneurysm (LVA) and global ejection fraction less than or equal to 20% who subsequently underwent radical LVA resection. The basic findings in the 20 survivors of surgery were significant improvement of global systolic LV function and more or less complete recovery of regional ejection fraction in the predominantly viable low and high lateral LV wall. This improvement was evident in patients with concomitant bypass grafting as well as in those with isolated and ungraftable lesions of the left anterior descending (LAD) coronary artery. We conclude that postinfarction anterior-apical LVA in a poorly functioning LV is suitable for surgical treatment, which can be accomplished with acceptable risk. All graftable stenotic major coronary arteries should be bypassed, in addition to the LVA resection, but a minority of patients with isolated, ungraftable LAD disease are likely to benefit from aneurysmectomy alone.

Late follow-up after repair of left ventricular aneurysm and (usually) associated coronary bypass grafting

This study assesses clinical and operative data (LV) aneurysm was repaired to determine factors that might predict in-hospital and long-term outcome. Long-term follow-up study was obtained in 296 of 298 patients undergoing LV aneurysm repair with or without coronary artery bypass grafting between 1974 and 1986. No patient had sustained a myocardial infarction within 2 weeks of surgery or was undergoing other concurrent cardiac surgery. The average age of the study patients was 57 +/- 9 years and the average ejection fraction was 35 +/- 13%. Ninety percent of the patients underwent concurrent bypass grafting, with an average of 2.2 +/- 1.3 grafts placed. Fourteen (5%) patients died in the hospital, with most deaths attributable to LV dysfunction. Advanced age and less extensive revascularization were correlates of in-hospital mortality. The 10-year survival was 57%, myocardial infarction-free survival 43%, and freedom from death, myocardial infarction and reoperative coronary surgery 41%. Advanced age, systemic hypertension, significant left main coronary artery narrowing and emergent operative status were multivariate correlates of long-term mortality. A low-risk population was defined by the absence of these risk factors, and high-risk by the presence of greater than or equal to 1 risk factors. The 10-year survival was 71% in the low-risk and 41% in the high-risk groups (p = .0006). The 10-year myocardial infarction free survival was 55% in the low-risk and 31% in the high-risk groups (p = 0.0017). LV aneurysm repair may be performed with acceptable in-hospital mortality, and the long-term risk may be stratified.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative analysis of regional systolic function with left ventricular aneurysm

Left ventricular aneurysm (LVA) remains a poorly understood entity, often resulting in congestive failure that is not consistently improved by standard resection with linear closure. Although other surgical approaches have been proposed, current methods to assess their effect on left ventricular function are not adequate. The purpose of the present study was to quantitatively define regional systolic function in patients with LVA and to assess acute changes in regional function after standard repair. Seven patients underwent resection of an anteroapical LVA. Intraoperative two-dimensional echocardiography was performed off cardiopulmonary bypass immediately before and after resection. In all patients, short-axis views at the papillary muscle (apex) level showed anteroseptal paradox and distorted geometry, whereas at the mitral valve (base), symmetric wall motion and geometry were preserved. Videotaped echo images were divided into octants by a floating axis fitted to internal landmarks. Myocardial area and midwall perimeter were obtained for each octant, and wall thickness was calculated at end diastole (ED), isovolumetric systole (IS), and end systole (ES). Wall thickening (delta t) for each segment was calculated as the percent increase in thickness from ED and averaged for all seven patients. At the apex level before resection, isovolumetric thinning occurred in the aneurysm as well as bordering segments, with delta t ranging from -17 +/- 5% (+/- SEM) in the anteroseptal segment to 12 +/- 6% posterolaterally (p less than 0.05). The isovolumetric bulge was followed by late-systolic thickening, however, with delta t ranging from 13 +/- 7% to 27 +/- 8% (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical improvement and long-term survival after surgical treatment of postinfarction left ventricular aneurysm

Left ventricular aneurysmectomy was performed on 45 men and 12 women (mean age 57 years) during a 12-year period. The hospital mortality was 14% and the cumulative 5-year survival 57% +/- 9 (SE). Of 35 survivors, 33 underwent a follow-up study (mean 28 months post-operatively). The mean cardiothoracic index fell from 0.58 +/- 0.08 (SD) to 0.51 +/- 0.04 and the mean left ventricular ejection fraction (EF) improved from 0.30 +/- 0.08 to 0.38 +/- 0.01 (both changes significant). Echocardiographic parameters showed no significant improvement in left ventricular function. The NYHA classification was I or II in 85% of the patients at follow-up, but in only 23% preoperatively. Preoperative EF greater than or equal to 0.30 was associated with 76% +/- 16 (SE) cumulative 5-year survival as compared with 31% +/- 12 when EF had been less than 0.30. In view of these results, left ventricular aneurysmectomy should be recommended for all symptomatic patients.

Does left ventricular aneurysmectomy improve ventricular function in patients undergoing coronary bypass surgery?

Fourteen consecutive patients undergoing left ventricular aneurysmectomy and coronary artery bypass grafting were studied by multiple gated ventricular scintigraphy at rest and during exercise before and at six weeks and six months after surgery. All had congestive heart failure and 12 angina pectoris. Before operation left ventricular ejection fraction fell significantly with exercise, as did the regional wall motion score. Six weeks after surgery all surviving patients were free of angina, with an improvement in functional class; the total exercise workload improved significantly, but resting left ventricular ejection fraction was unchanged; the regional wall motion score improved in both the anterior and left anterior oblique projections, although extensive areas of abnormal contraction persisted. Exercise left ventricular ejection fraction improved significantly after operation at six weeks, and previous exercise induced abnormalities of regional contraction were abolished. Six months after operation angina pectoris had recurred in one patient, but there was no further change in ventricular function in the remainder. Although resting ejection fraction is not improved, symptoms, exercise workload, and exercise ventricular function can be improved by aneurysmectomy and coronary artery bypass grafting, but the respective contribution of these two procedures remains uncertain.

Phase image characterization of localized and generalized left ventricular contraction abnormalities

To evaluate their phase image characteristics, 61 patients with varying left ventricular contraction abnormalities were studied. In 16 normal patients, the left ventricular phase image revealed a homogeneous pattern, a narrow bell-shaped histogram and an orderly spatial progression of phase angle (phi). In 16 patients with segmental abnormalities, the left ventricular phase image showed a region of uniformly delayed phase angle corresponding to the site of segmental abnormality, a discrete secondary histogram peak and a discontinuous, but orderly, spatial progression of phase angle. The mean phase angle (phi) (23.6 +/- 15.7 degrees) and its standard deviation (17.6 +/- 7.2 degrees) differed from the normal group (7.6 +/- 11.1 degrees, p less than 0.002 and 8.9 +/- 2.8 degrees, p less than 0.001). The percent of end-diastolic volume involved in the segmental abnormality, calculated using phase data in 13 of these and in 11 additional patients with a left ventricular aneurysm on ventriculography, correlated well with the percent akinetic segment on scintigraphic (r = 0.78) and angiographic (r = 0.84) study. In 18 patients with generalized abnormalities, the left ventricular phase image revealed multiple regions of inhomogeneous phase angle, a grossly irregular histogram and a disorderly spatial progression of phase angle. The mean phase angle (56.4 +/- 23.9 degrees) and standard deviation (27.3 +/- 7.1 degrees) differed from values in the normal group and from patients with segmental contraction abnormalities (both p less than 0.001). The mean phase angle and its standard deviation in scattered regions with abnormally prolonged phase angle differed significantly from abnormal regions in patients with segmental abnormalities (both p less than 0.001). These patterns of left ventricular phase angle demonstrate characteristics that may help differentiate between ventricles with segmental and generalized contraction abnormalities. Their relation to underlying pathophysiology and potential clinical implications should be considered.