Prognostic value of echocardiographic evaluation of septal function in acute anteroseptal myocardial infarction

Electrocardiographic diagnosis of ventricular septal infarction

To find electrocardiographic criteria for ventricular septal infarction, two series of ECGs were studied, all without fascicular/bundle branch block and complete heart block. One series consisted of the ECGs recorded at thallium-201 scintigraphy in 49 patients 2-3 weeks after an acute myocardial infarction (AMI): in this series the 14 patients with a defect in the septal wall of the left anterior oblique view were compared with the 35 without. The other series consisted of the last premortal ECGs in 20 AMI patients with and in seven without a septal involvement of the infarct at autopsy. The best criterion from earlier literature ws absence of a q wave in lead V6, showing a sensitivity of 53% in the combined scintigraphy and autopsy series. The predictive value of a positive test was 75%. The very first QRS vector in the frontal plane tended to discriminate better than absence of a q in lead V6. With a similar predictive value, 71%, the sensitivity of a deviating vector (+ 120 degrees to -60 degrees and -120 degrees to -180 degrees) was 65% in the combined scintigraphy and autopsy groups. Most of the patients with a deviating vector showed this on admission. The clinical importance of an early diagnosis of septal involvement in AMI remains to be settled.

Long-term prognostic significance of M mode echocardiography in young men after myocardial infarction

OBJECTIVE

To evaluate the power of measurements of left ventricular size and function for predicting long term (82 month) mortality by performing echocardiography in 97 men who had survived an acute myocardial infarction.

SETTING

University hospital specialising in cardiology.

PARTICIPANTS

97 consecutive male patients who had survived a myocardial infarction.

MAIN OUTCOME MEASURES

The additive prognostic value of functional measurements to that provided by primary risk factors (smoking habits and lipoprotein levels), radiological heart size, exercise capacity, and number of major coronary arteries with haemodynamically significant stenoses was evaluated. An echo index was calculated from three echocardiographic variables (yielding one score point each if: left ventricular diameter at the end of diastole (LVDD) > or = 5.7 cm, left ventricular fractional shortening < or = 24%, and E point-separation (EPSS) > or = 10 mm).

MAIN OUTCOME

17 cardiac deaths occurred during follow up.

RESULTS

Univariate analysis showed that treatment with loop diuretics for heart failure (P < 0.01), LVDD (P < 0.01), left ventricular diameter at the end of systole (LVDS) (P < 0.001), left atrial diameter (P < 0.001), fractional shortening (P < 0.05), and echo index (P < 0.001) were all associated with cardiac death. Angiographically determined regional wall motion disturbances (P < 0.005) and angiographic ejection fraction (P < 0.001) were also associated with cardiac death, as was the number of major coronary arteries with significant stenosis (P < 0.05). When all significant echocardiographic variables from univariate analysis were entered into Cox proportional hazards survival analysis, LVDS and left atrial diameter contributed independently to the prediction of cardiac death. If angiographic data were also entered into the model, the echo index made an independent contribution to the prediction of cardiac death.

CONCLUSIONS

Among young male patients with a previous myocardial infarction, a simple M mode echocardiographic examination can identify high and low risk patients and improve the prediction of cardiac death made from clinical information, exercise test, chest x ray and angiographically determined ejection fraction.

Relationship between septal perfusion, viability, and motion before and after coronary artery bypass surgery

The etiology of abnormal interventricular septal motion occurring after open-heart surgery using cardiopulmonary bypass has not been clarified. Intraoperative ischemic septal injury has been proposed as one explanation for this finding. To examine this possibility, resting septal perfusion and viability were studied using rest and redistribution thallium-201 scintigraphy in 16 patients before and after coronary artery bypass surgery. The results were compared with septal motion on preoperative and postoperative resting gated blood pool scans. Preoperatively, septal thallium uptake was normal in 10 of 16 patients, and septal motion was normal in 14 of 16. Postoperatively, septal thallium uptake was normal in 11 of 16 patients, while septal motion was abnormal in all. Thus abnormal postoperative septal motion is usually associated with normal septal perfusion and viability on thallium scans and therefore is not the result of septal ischemic injury in a majority of patients.

Mechanism underlying the absence of ischemic changes on the exercise electrocardiogram in patients with abnormal exercise thallium-201 imaging and coronary artery disease

Patients with coronary artery disease may have reversible abnormalities on a thallium myocardial perfusion study without simultaneous ischemic changes on the exercise electrocardiogram, but the mechanisms responsible for this disparity have not been fully elucidated. A group of 37 patients with angiographically demonstrated coronary artery disease and abnormal thallium perfusion imaging were divided into two groups on the basis of their exercise electrocardiographic ST segment response. Thirteen patients (Group A) had no significant electrocardiographic changes with exercise, while 24 patients (Group B) had ST changes consistent with ischemia during the test. There were no significant differences in clinical or angiographic characteristics between the two groups. Stress test results showed a similar mean duration of exercise in the two groups (6.2 +/- 1.8 versus 6.7 +/- 2.5 min, p = NS), but the patients in Group A achieved a significantly lower mean maximal heart rate (117 +/- 26 versus 132 +/- 21 beats/min, p less than 0.05) and mean maximal double product (19,650 +/- 5116 versus 22,650 +/- 4871, p less than 0.05). There was no consistent pattern of thallium perfusion abnormality noted in Group A to suggest that a particular region of electrically silent myocardium was responsible for ischemia in the absence of electrocardiographic changes. These results suggest that exercise thallium-electrocardiogram discordance is mediated by the level of myocardial workload achieved. An abnormal perfusion scan accompanying an exercise electrocardiogram which does not demonstrate any ischemic ST change may occur when there is sufficient increase in myocardial oxygen demand to result in differential augmentation of myocardial blood flow, but insufficient imbalance of supply and demand to result in signs of ischemia on the surface electrocardiogram.

Functional consequences of interventricular septal involvement in right ventricular infarction: echocardiographic, clinical, and hemodynamic observations

Although ischemic involvement of the interventricular septum (IVS) may occur in patients with right ventricular infarction (RVI), the potential functional significance of such involvement has not been explored. In 10 patients with hemodynamically evident RVI, ischemic involvement of the IVS was assessed by measuring IVS systolic thickening on M-mode echocardiography. Six patients (group I) had decreased IVS systolic thickening, an echocardiographic indicator of ischemia, or infarction, while four (group II) did not. Group I had significantly higher right ventricular filling pressures (19 +/- 3 vs 12 +/- 5 mm Hg, p = 0.04) and right ventricular end-diastolic echocardiographic dimensions (32 +/- 8 vs 20 +/- 3 mm; p = 0.02) than group II. Paradoxic septal motion was noted only in group I patients (p = 0.01). Left ventricular filling pressures, left ventricular end-diastolic dimensions, and systolic thickening of the left ventricular posterior wall (LVPW) were not significantly different between the groups. Three group I patients died; all had decreased systolic thickening of both the IVS and LVPW. In each, autopsy confirmed infarction of the right ventricular free wall, IVS, and LVPW. In patients with right ventricular infarction, ischemic involvement of the interventricular septum may have important consequences for both right and left ventricular function.

Immediate detection of early high-risk patients with acute myocardial infarction using two-dimensional echocardiographic evaluation of left ventricular regional wall motion abnormalities

Forty-three patients with acute myocardial infarction (AMI) were studied with serial two-dimensional echocardiography (2DE) to define a high-risk subset for in-hospital cardiovascular complications including pump failure, life-threatening arrhythmias, or death. A 2DE segment score was developed representing the extent of left ventricular (LV) regional wall motion abnormality (WMA) which was correlated with peak total creatine kinase (CK) release. Patients with transmural AMI had a segment score of 7.2 +/- 3.8, whereas those with nontransmural AMI had a segment score of 4.7 +/- 3.4 (p less than 0.025). Peak total serum CK enzyme level correlated statistically with segment score but with a low correlation coefficient. Thirteen (30%) of the 43 patients had an in-hospital complication and their segment score was 10.0 +/- 3.4 compared to 4.6 +/- 2.7 in those patients without a complication (p less than 0.005). A segment score greater than or equal to 8 was found in 11 of 13 (85%) of those who suffered a cardiac complication and in only five (16%) of the 30 patients without complication (p less than 0.05; sensitivity 85%, specificity 83%). Patient's initial clinical Killip classification was specific but very insensitive in predicting an early complicated course. Thus, 2DE study of LV regional wall motion can predict in the immediate post-AMI stage the in-hospital likelihood of such patients developing a cardiovascular complication during acute myocardial infarction.

Complimentary roles of cardiac ultrasound and cardiovascular nuclear medicine

This review is directed at the clinically useful highlights of ultrasound and radionuclide testing in adults with coronary and valvular heart disease, intracardiac shunts, and hypertrophic and congestive cardiomyopathies. As a clinical toto, the radionuclide procedures are currently more useful than ultrasound examination in evaluating patients with known or suspected coronary artery disease. This includes both primary diagnosis and the more accurate estimation of left ventricular function in the presence of segmental asynergy. In patients with valvular disease, the radionuclide procedures are only indirectly useful, while the ultrasound examination is more often diagnostic. These two techniques are complimentary to one another in their ability to noninvasively evaluate and monitor both chamber size and ventricular function in virtually all patients. Recent research involving noninvasive ventricular imaging during physiologic and pharmacologic intervention holds promise for a more sophisticated noninvasive approach to patient management.