Postextrasystolic T wave changes and angiographic coronary disease.

The significance of postextrasystolic T wave changes in beats following induced extrasystoles was assessed by angiography in 55 patients. These T wave changes were found in 81 per cent of coronary artery disease patients but also in 68 per cent of patients with normal coronary arteries (PNS). All patients with normal baseline electrocardiograms and normal coronary arteries showed postextrasystolic T wave changes. In electrocardiographic leads corresponding to the distribution of major coronary arteries, T wave changes occurred just as frequently when the artery was normal (54%) as when the artery was stenosed (55%). Left ventricular asynergy was not associated with an increased frequency of postextrasystolic T wave changes and in fact ejection fraction was greater end-diastolic pressure lower in patients with T wave changes. Thus, postextrasystolic T wave changes appear not to be useful in diagnosing or localising coronary artery disease.     

Evaluation of postextrasystolic T wave alterations in identification of patients with coronary artery disease or left ventricular dysfunction

This study was performed (1) to assess the value of postextrasystolic T wave alterations in identification of patients with cardiac disease and (2) to determine if their frequency depends on length of compensatory pause. In 52 patients a pacing catheter was placed in the right ventricular (RV) apex, and premature beats were programmed to occur 30 msec beyond RV refractory period. Postextrasystolic T wave alterations occurred in 32 patients, 13 with an 19 without coronary artery disease (CAD) (NS). Such alterations were also not related to presence of abnormal left ventricular (LV) ejection fraction (less than 0.55) or end-diastolic pressure (greater than 12 mm Hg). In 33 patients, premature beats were also introduced 330 msec beyond the RV refractory period to compare effects of long and short compensatory pauses on frequency of postextrasystolic T wave alterations. When the pause was near maximal, 18 patients had alterations in 60 ECG leads; when it was shorter, seven patients had alterations in 10 leads (p less than 0.001). Thus, judging from provoked postextrasystolic T wave alterations, such spontaneous changes appear neither sensitive nor specific in the identification of patients with cardiac disease. The frequency of postextrasystolic T wave changes depends on the length of the compensatory pause.     

Significance of minor ST segment and T wave changes in the resting electrocardiogram of asymptomatic subjects.

Sixteen thousand resting electrocardiograms were performed on 14000 United Kingdom professional aircrew and air traffic control officers over a two-year period; 103 asymptomatic men with minor ST segment and T wave changes at rest were assessed by exercise electrocardiography and 19 responded abnormally. Five subjects had proven coronary artery disease, one hypertrophic obstructive cardiomyopathy, and one left ventricular dilatation on echocardiography. Eleven subjects were not investigated, of whom three had strongly positive exercise responses. One subject had a false positive response and assuming a false negative response of less than 2 per cent, then a sensitivity of 80.0 per cent, a specificity of 89.1 per cent, a predictive value for the exercise electrocardiogram of 44.46 per cent and for the resting electrocardiogram of 7.8 per cent is obtained. T wave changes induced by hyperventilation were common (53.4% of all). Ten (18.2%) subjects with hyperventilation-induced T wave changes responded abnormally to exercise, three having angiographically proven coronary artery disease lending little support to the contention that the two entities rarely coexist. In spite of the low return from routine electrocardiograms in a population with a low prevalence of coronary artery disease, three-eighths of those with significant coronary artery disease presented with minor ST segment and T wave changes on their resting electrocardiograms.     

The diagnostic value of resting electrocardiography in stable coronary artery disease

The relation of resting electrocardiographic (ECG) patterns to angiographic features was assessed in 566 patients with chest pain regarded as definite or probable stable angina pectoris. The indications for catheterization in each patient were determined at the discretion of the attending physician. All patients underwent diagnostic coronary angiography (clinically important coronary artery disease was defined as > or = 70 per cent narrowing of the diameter of at least one major vessel or > or = 50 per cent of the left main coronary artery) and standard 12 lead electrocardiography which was interpreted by 2 cardiologists independently in coordinating centre. The signs of impaired coronary blood flow were assessed by abnormalities of repolarization (among others S-T segment, the T wave), depolarization and presence of disturbances of cardiac rythm. The resting routine electrocardiogram was assigned to one of three categories: normal, nonspecific abnormalities or typical for coronary insufficiency. The typical pattern for ischemia was present in 104 patients (18%), nonspecific abnormalities were present in 185 patients (33%) and electrocardiogram was normal in 277 patients (49%). Sensitivity and specificity of the typical for coronary insufficiency resting ECG was calculated: 23% and 87% respectively for the entire group, 33% and 81% in women, 20% and 93% in men. In the group with normal resting electrocardiographic pattern 55% of patients have significant stenosis in at least one major coronary artery.     

New coronary artery disease index based on exercise-induced QRS changes

Exercise-induced changes in Q, R, and S wave amplitudes have been reported to detect coronary artery disease but with low specificity, low sensitivity, or both; it was hypothesized that their incorporation into a composite index (Athens QRS score) might improve specificity and sensitivity. For this purpose 246 patients were analyzed retrospectively and 160 prospectively. All patients underwent maximal exercise testing with a standard Bruce protocol and coronary arteriography as part of the diagnostic evaluation for possible or definite coronary artery disease. The Athens QRS score was decreased as the number of obstructed coronary arteries increased (normal coronary arteries = 7.85 +/- 5.23 mm, one-vessel disease = 5.2 +/- 5.3 mm, two-vessel disease = -0.85 +/- 5.4 mm, three-vessel disease = -3.5 +/- 5.8 mm; p less than 0.0001); the score was unrelated to exercise-induced ST segment depression, and negative (less than 0) scores were always associated with coronary artery disease. An Athens QRS score of 5 mm predicted coronary artery disease with sensitivity ranging from 75% to 86% and a specificity ranging from 73% to 79%, values higher than those of the Q wave (75% and 50%, respectively), R wave (65% and 55%), and S wave (70% and 10%) and of the ST segment depression (62% and 70%). It is concluded that exercise-induced changes in the QRS complex provide a useful index not only for the diagnosis but also for the assessment of severity of coronary artery disease.     

The significance of hypotension developing during treadmill exercise testing

The significance of hypotension developing during treadmill exercise testing was evaluated and correlated with the findings at cardiac catherization in two groups of patients. Twenty-five patients (Group I) had a fall in systolic pressure during exercise and were compared to 50 consecutive unselected patients (Group II) with a normal blood pressure response. Clinical characteristics were similar in both groups. Females comprised 48 per cent of the patients in Group I and only 30 per cent in Group II. The incidence of significant coronary artery disease was not different when the two groups were compared as a whole, 56 per cent in Group I and 36 per cent in Group II (P = NS). When males and females were considered separately, it was noted that the incidence of coronary artery disease was higher in hypotensive males (77 per cent) when compared to control males (40 per cent) (p < 0.01). Females in both groups had a lower but comparable incidence of coronary artery disease (25 per cent and 27 per cent, respectively). Resting hemodynamics and angiographic characteristics, such as contraction abnormalities, and the number and distribution of diseased coronary vessels, were similar in both groups of patients. These findings suggest that hypotension in females does not necessarily connote coronary artery disease. Males with hypotension have a higher incidence of coronary artery disease, but the extent and distribution of their disease is no different from that of patients with a normal blood pressure response to exercise.     

Left ventricular ejection fraction in severe chronic obstructive airways disease.

The subject of left ventricular involvement in chronic obstructive airways disease is controversial. We measured left ventricular ejection fraction (LVEF) in 120 patients with severe chronic obstructive airways disease, 92 of them acutely decompensated and 28 stable. A bedside radionuclide technic using a scintillation probe was used to measure LVEF. Of the 28 patients with acute respiratory failure, LVEF was normal (larger than or equal to 55 per cent) in 60 and subnormal in 32. Of the 28 patients with stable chronic obstructive airways disease, LVEF was normal in 12 and low in 16. Coronary artery disease could be demonstrated clinically or at autopsy in 13 of the patients with acute and in 7 of the patients with stable chronic obstructive airways disease. LVEF was 28 plus or minus 10.4 per cent (average plus or minus SEM) in the patients with acute chronic obstructive airways disease and coronary artery disease which was significantly different (P smaller than 0.001) from LVEF in patients without coronary artery disease (61 plus or minus 1.9 per cent). In the patients stable with chronic obstructive airways disease and coronary artery disease, LVEF was (42 plus or minus 3.5 per cent), significantly different (P smaller than 0.001) from LVEF in those without coronary artery disease (55 plus or minus 2.1 per cent). There was no relationship between LVEF and arterial oxygen, or carbon dioxide tension, or pH. Results suggest that LVEF is normal in patients with severe lung disease alone and that reduced LVEF in patients with chronic obstructive airways disease can reasonably be ascribed to coronary artery disease.     

Effect of clofibrate on progression of coronary disease: a prospective angiographic study in man

Lowering blood lipids has been invoked as a means of controlling future coronary events. In this prospective study, the effect of a lipid-reducing agent clofibrate (2 gm. daily) on extent of coronary artery disease was investigated. Forty patients, 32 having aortocoronary bypass, six having Vineberg operations, two having neither, were placed double-blind in placebo (24 patients) and clofibrate (16 patients) groups, and restudied by selective coronary angiography one year later. An additional 24 patients dropped from the study due to adverse drug reactions in eight. Each patient's right, left, anterior descending, and circumflex coronary arteries (with their branches) were separately rated according to degree of obstruction. The clofibrate group showed a significantly greater fall in triglyceride than did the placebo group (?13.7 per cent versus +2.3 per cent; p = 0.45). In the clofibrate group, 19 out of 64 coronary arteries (29.6 per cent) showed progressive coronary narrowing, not significantly different from the placebo group (24 out of 96 coronary arteries narrowed, 25 per cent; p = 0.26). No significant differences between drug groups emerged when the data were corrected for degree of fall of blood lipids, initial lipoprotein type, or effect in bypassed versus nonbypassed vessels (p always >0.2). Regression of coronary artery disease was not seen. We conclude that clofibrate did not significantly influence the rate of progression of coronary artery disease in a one-year period.     

Coronary artery disease in young patients: arteriographic and clinical review of 40 cases aged 35 and under

Coronary arteriography was performed in 60 patients aged 35 or less with suggested coronary artery disease (CAD). Twenty patients (Group 1) had normal coronary arteries and 40 patients (Group 2) had one or more obstructive lesions. The left anterior descending artery was commonly involved followed by the right coronary and left circumflex arteries. The right coronary artery was most commonly completely obstructed. Single-vessel disease (50 per cent or greater obstruction) was found in 60 per cent of the patients, an incidence that is considerably higher than in studies of older patients. A total of 1.6 diseased vessels per patient was present. A hyperlipoproteinemia (HLP) was found in 68 per cent of Group 2 patients. Patients in Group 2 with an HLP had significantly more CAD than Group 2 patients with normal lipoproteins. The incidence of the following clinical features were not significantly different in Groups 1 and 2: typical angina, atypical angina, positive family history, smoking, hypertension, obesity, abnormal electrocardiogram, positive treadmill test, HLP, and diabetes mellitus. A fourth heart sound and a history of a myocardial infarction were significantly common in Group 2. Since almost all of the previously reported cases of myocardial infarction with normal coronary arteries have occurred in young patients, history of a myocardial infarction does not assure the presence of obstructive coronary artery lesions. It is suggested that coronary arteriography is a justifiable procedure in a young patient who presents with a clinical picture that is either compatible with or cannot be clearly distinguished from CAD.     

Variable patterns of ST-T abnormalities in patients with left ventricular hypertrophy and normal coronary arteries.

BACKGROUND--Classically, the ST-T configuration in the electrocardiogram of patients with left ventricular hypertrophy is said to have a typical pattern of ST depression together with asymmetrical T wave inversion (the so-called left ventricular strain pattern). However, many patients with left ventricular hypertrophy may also have ischaemic heart disease. To revise the electrocardiographic criteria for left ventricular hypertrophy the ST-T configuration in patients with left ventricular hypertrophy documented by echocardiography and with normal coronary arteries was assessed. METHODS--24 patients were selected for this study. All had left ventricular hypertrophy documented by echocardiography, normal coronary arteries by cardiac catheterisation, and ST and/or T wave abnormalities in the lateral leads of their electrocardiogram. There were eight patients with aortic valve disease and 16 with hypertension who had coronary angiography as part of an investigation into the risk factors of sudden cardiac death caused by hypertensive left ventricular hypertrophy. No patient was receiving digitalis preparations or had electrolyte disturbances, and none had a previous myocardial infarction or ventricular conduction defect. RESULTS--Typical electrocardiographic evidence of left ventricular strain was found in approximately two thirds (63%) of patients and 95% of this subgroup had asymmetrical T wave inversion. Flat ST segment depression, with or without T wave inversion or isolated T wave inversion (symmetrical or asymmetrical) in the anterolateral leads, was seen in the remaining 37% of patients. CONCLUSIONS--These findings indicate that left ventricular hypertrophy without coronary artery disease can cause variable types of ST-T abnormalities in the anterolateral leads including the typical left ventricular strain pattern and non-specific ST-T changes. Non-specific abnormalities could not be distinguished from those of coronary artery disease and may adversely affect the accuracy of the electrocardiographic criteria for the diagnosis of left ventricular hypertrophy because they do not accord with the criteria for left ventricular strain.     

Enhanced rate of progression of coronary artery disease following aortocoronary saphenous vein bypass surgery

To evaluate the fate of the coronary arteries after aortocoronary bypass, 40 patients underwent serial selective coronary angiographic studies 1 year apart, and the frequency of progression of coronary artery disease was estimated. Thirty-two had saphenous vein bypass surgery after the first procedure, six had Vineberg operations, and two had no interim operation. In each patient, the right, left, anterior descending and circumflex coronary arteries (including their branches) were separately evaluated. Progressive narrowing was evident in 31 of 50 (62 per cent) bypassed vessels and in only 11 of 113 (9.7 per cent) nonbypassed arteries (p < 0.001). Coronary arteries with moderate to severe obstruction initially (50 to 99 per cent occluded) manifested progressive disease more frequently (33 of 70 arteries) than did arteries that were normal or mildly narrowed initially (4 of 71) (p < 0.001). Considering only those vessels with 50 to 99 per cent obstruction initially, 27 of 35 (77 per cent) of the bypassed arteries and only 6 of 35 (17 per cent) of the nonbypassed arteries showed progression (p < 0.001). We conclude that moderately or severely narrowed coronary arteries are more likely to show progressive narrowing than normal or mildly obstructed ones and that progression of coronary disease is greater in bypassed vessels than in nonbypassed vessels. In view of potential graft closure, the implications of these findings must be considered in selecting patients for aortocoronary bypass.     

Correlation of heart size with clinical and hemodynamic findings in patients with coronary artery disease.

The clinical, hemodynamic, and angiographic findings were correlated with the heart size in 207 patients with proved coronary artery disease. Cardiomegaly was noted in 34 patients and normal heart size in 173. In these two groups, the patients' age range, duration of disease, and history of myocardial infarction were similar. There was no statistical difference in incidence of shortness of breath, hypertension, left ventricular hypertrophy, or abnormal glucose tolerance. Patients with cardiomegaly had a significantly higher incidence of congestive heart failure (26 per cent) as compared to patients with normal heart size (2.9 per cent) (P less than 0.001). Patients with enlarged heart presented a high incidence of anterior wall or multiple myocardial infarction (73 per cent) (P less than 0.001). The cardiomegaly group had a high incidence of elevated end-diastolic volumes, elevated end-diastolic pressures, and diminished ejection fractions when compared to patients with normal heart size (P less than 0.01). Double and triple coronary artery disease was more frequent in patients with cardiomegaly and total coronary score was also higher in this group (P less than 0.005). Asynergy was present in 55 per cent of patients with normal heart size but in 82 per cent of those with enlarged hearts (P less than 0.01). The group of patients with cardiomegaly and documented congestive heart failure had ejection fractions less than 0.30. Cardiac catheterization is probably not advisable in these patients in the absence of associated significant mitral regurgitation, ventricular septal defect, or ventricular aneurysm.     

Evaluation of left ventricular residual function using postextrasystolic potentiation. Relation between systolic time intervals and angiographic study

The effects of postextrasystolic potentiation (PESP) on systolic time intervals and left ventricular wall motion were studied during diagnostic cardiac catheterization in 20 patients (4 normal individuals, 11 patients with coronary artery disease and 5 patients with idiopathic dilated cardiomyopathy). Postextrasystolic changes in the aortic pressure and systolic time intervals were measured from the electrocardiogram and aortic pressure tracing. After a micromanometer-tipped catheter was positioned in the ascending aorta just above the aortic valve, a single ventricular premature beat was introduced using an R-wave coupled stimulator. PESP was then studied during left ventriculography which was undertaken simultaneously in the right anterior oblique 30 degrees and left anterior oblique 60 degrees positions. Following two or three normal sinus beats, a right ventricular extrastimulus was delivered again under the same stimulating condition. PESP in all patients caused a decrease in the ratio of the preejection period to the left ventricular ejection time (PEP/ET). The average percent decrease was 21% (from 0.429 +/- 0.162 to 0.339 +/- 0.102, p less than 0.001). The left ventricular ejection fraction (EF) increased in all patients with PESP from 0.52 +/- 0.20 to 0.61 +/- 0.17 (p less than 0.001). The postextrasystolic changes in the PEP/ET ratio and EF were greater in patients with low cardiac performance. There was a good correlation (r = -0.85, p less than 0.001) between the changes in the EF and those in PEP/ET in PESP. Thus, it is possible to determine left ventricular residual function (the postextrasystolic change in the global EF) using the postextrasystolic change in PEP/ET in patients with coronary artery disease and dilated cardiomyopathy.     

Postextrasystolic T wave changes in normal canine hearts

Premature ventricular beats were induced at variable coupling intervals and postextrasystolic T wave changes were observed following various postextrasystolic cycle lengths in 19 closed chest dogs with normal hearts. Following relatively longer postextrasystolic cycle lengths, reversal of the T wave polarity was seen in six dogs (31%), only T wave amplitude changes were seen in 6 dogs (31%), and no significant T wave changes were seen in seven dogs (38%). It was concluded that postextrasystolic T wave changes occur in normal hearts and have no useful diagnostic values.     

Noninvasively induced postextrasystolic potentiation of ischemic and infarcted myocardium in patients with coronary artery disease.

To evaluate noninvasively-induced postextrasystolic potentiation (PESP) of ischemic or apparently infarcted regions of myocardium, an external mechanical cardiac stimulator (develoepd by Zoll) was used to induce ventricular extrasystoles during M-mode echocardiography in 29 patients with coronary artery disease and in four control subjects. Twenty-five patients had > 75 per cent stenosis of the left anterior descending artery including 13 with ECG evidence of anteroseptal myocardial infarction; 21 patients had > 75 per cent stenosis of the right coronary and/or left circumflex arteries, including 11 with ECG evidence of inferior and/or posterior myocardial infarction. Twenty-four regions with reduced wall excursion showed varying effects of PESP: eight regions improved to the normal range, while 16 did not. Twelve of the latter had ECG evidence of prior infarction. Similarly, regions of asynergy that did not respond at all to PESP were usually, but not always, seen in patients with infarctions. Based on prior ventriculographic-histopathologic correlates, non-responding regions are probably totally scarred with irreversible contraction abnormalities, whereas regions with evidence of contractile reserve are potentially viable. Because the ECG and resting echocardiogram are not totally accurate predictors of contractile reserve, noninvasively induced PESP may be a useful adjunct technique in delineating local contractile reserve in patients with echocardiographic evidence of hypocontractile myocardium of uncertain viability.     

Coronary artery disease in patients dying from cardiogenic shock or congestive heart failure in the setting of acute myocardial infarction.

Pathological findings in the heart and particularly in the coronary arteries are reported from 70 patients dying from pump failure after acute myocardial infarction. Fifty of the patients had died in cardiogenic shock, the remainder from refractory congestive heart failure. Three-vessel disease (greater than or equal to 75% occlusion) was present in 68 per cent of the group with cardiogenic shock but in only 35 per cent of those with fatal congestive heart failure (P less than 0-02). In both groups there was an almost equal incidence (84% for cardiogenic shock and 80% for congestive heart failure) of severe disease (greater than or equal to 75% occlusion) over a long segment of the left anterior descending artery. However, there were differences between the two groups regarding the involvement of the other coronary arteries. Whereas patients with cardiogenic shock generally showed severe disease over a long segment in all coronary arteries, in 60 per cent of those with congestive heart failure there was only local severe narrowing of the right coronary artery with little or no narrowing of the peripheral part. Similarly, 60 per cent of those with congestive heart failure had less than 75 per cent narrowing in the left circumflex artery. These anatomical findings may be of relevance with regard to desirability of acute coronary bypass surgery in patients with pump failure after acute myocardial infarction.     

The role of ambulatory ST-segment monitoring in the diagnosis of coronary artery disease: comparison with exercise testing and thallium scintigraphy

The value of ambulatory ST-segment monitoring in the detectionof underlying coronary artery disease was investigated in onehundred consecutive patients who underwent exercise testingand coronary arteriography for chest pain. Forty-seven alsohad thallium-201 radioisotope imaging performed Six of the 26 patients with normal coronary arteries and 52of the 74 patients with significant coronary artery diseasehad ST-segment changes during 48 h of ambulatory monitoring(sensitivity 77%). In comparison, the sensitivity of conventionalexercise testing was 73% and specificity was 81%. Previous myocardialinfarction did not influence the results, but patients withpoor left ventricular function more often had absence of ambulatoryST-segment changes. Three-vessel coronary artery disease wasdetected more efficiently (sensitivity 80%), compared with singlevessel disease (sensitivity 50%). Thallium scintigraphy demonstrateddefects of uptake in nine patients without ambulatory ST-segmentchanges (sensitivity 82%, specificity 71%). The majority ofthese patients had small inferior or posterior defects in thalliumuptake Only one patient with ambulatory ST-segment changes had normalcoronary arteries and demonstrable spasm. Thus, ambulatory ST-segmentmonitoring is as valuable as stress testing in the detectionof coronary artery disease and in addition helps detect patientswith coronary spasm and normal coronary arteries.     

Changes of Q wave amplitude during exercise for the prediction of coronary artery disease

We have examined the changes of Q wave amplitude during exercise in 156 patients with chest pain with a view to improving the accuracy of stress testing for the diagnosis of coronary artery disease. Coronary arteriography showed significant disease in 127 patients and normal arteries or minimal disease in 29. The Q wave amplitude was measured in lead CM5 from the computer-derived average of 25 consecutive beats immediately before and at the peak of maximal treadmill exercise. The amplitude was greater in the normal subjects at rest and increased with exercise, but the reverse occurred in those with coronary disease. Using the criterion of decrease or no change of Q wave amplitude during exercise as indicating a positive test, the discriminative capacity of Q wave changes was equivalent to that of ST segment depression and was maintained when patients with myocardial infarction were excluded. Using either an abnormal Q wave or ST segment response to exercise improved the test's sensitivity with a loss of specificity but no change of predictive value. In 42% of patients with coronary disease when both the Q wave and ST segment exercise responses were abnormal coronary disease was predicted with an accuracy of 91%. Analysis of subgroups of patients with coronary artery disease suggested a possible explanation for the observed changes in Q wave amplitude, measurement of which can improve the stress test's accuracy for predicting obstructive coronary artery disease.     

A natural history study of the prognostic role of coronary arteriography

Coronary cinearteriograms, clinical records, and left ventriculograms of 304 patients studied for evaluation of chest pain were reviewed. Clinical and follow-up data on survival of the normal subjects and the nonoperative group with abnormal arteriograms are presented.Ninety-two per cent of patients with typical angina pectoris had serious coronary occlusive disease. Ninety-eight per cent of patients with relatively normal coronary arteriograms survived for one to 60 or more months (mean follow-up period 24 months).There was a high mortality rate when the left main coronary artery was involved (47 per cent) and when the left coronary anterior descending branch was seriously occluded (28 per cent when arteriographic scores were high and 14 per cent when total scores were low) and a low mortality rate (0 to 7 per cent) when the LAD was normal. Mean follow-up interval in these groups was 19 months.The mortality rate was nearly three times greater when patients had QRS changes on ECG of prior myocardial infarction and six times greater when left ventricular contraction was significantly impaired.     

Predictive value of electrocardiographic patterns in localizing left ventricular asynergy in coronary artery disease.

Transmural myocardial infarction by ECG (ECG-MI) was correlated with left ventricular asynergy by biplane left cineventriculography in 200 patients with coronary artery disease. The ability of individual ECG-MI patterns to predict and correctly localize asynergy was: anterior--98 per cent (43 of 44), inferior--82 per cent (36 of 44), true posterior--73 per cent (11 of 15). Of various combinations of criteria for true posterior ECG-MI, the pattern of an R wave and upright T wave in Lead V1 was most predictive of posterior asynergy--80 per cent (8 of 10). The LAO projection demonstrated a wall motion abnormality not appreciated in the RAO in 8 per cent (10 of 122) of cases of inferoposterior asynergy and enhanced assessment of asynergy in 30 per cent (36 of 122) of cases. It is concluded that: (1) ECG-MI has a high predictive accuracy for left ventricular asynergy, (2) an R-wave and upright T wave in Lead V1 is the best ECG predictor of posterior asynergy, and (3) the LAO projection makes an important contribution to the assessment of regional asynergy in coronary artery dieseas.