Effects of recent and remote infarction on the predictive accuracy of the ST segment/heart rate slope

The exercise electrocardiographic ST segment/heart rate slope accurately identifies three vessel coronary disease in patients with stable angina, but the method is less accurate in predischarge testing after recent myocardial infarction. To assess the effect of both recent (less than 3 weeks) infarction and remote (greater than 8 weeks) Q wave infarction on the ST segment/heart rate slope, the predictive value of a slope greater than 6.0 microV/beat per min for the identification of three vessel coronary artery disease was evaluated in 113 patients. The 58 patients with stable angina, including 17 with remote Q wave myocardial infarction, were similar to the 55 patients with recent myocardial infarction with respect to age and peak exercise heart rate. In patients with stable angina and no prior Q wave myocardial infarction, an ST segment/heart rate slope greater than 6.0 had a sensitivity of 92% (11 of 12), a specificity of 97% (28 of 29) and a positive predictive value of 92% (11 of 12) for three vessel coronary artery disease. In patients with stable angina and remote Q wave infarction, sensitivity was 83% (5 of 6), specificity was 91% (10 of 11) and positive predictive value was 83% (5 of 6). After recent infarction, test specificity for three vessel disease was preserved at 95% (39 of 41), but test sensitivity was poor (3 of 8). This was confirmed by evaluation of six additional recent patients with infarction and three vessel disease. Among the combined group with recent infarction, test sensitivity for three vessel disease was only 29% (4 of 14), significantly lower than in patients with stable angina (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized double-blind trial of intravenous streptokinase for acute myocardial infarction

To determine the efficacy of intravenously administered streptokinase (SK) on infarct artery patency, global left ventricular (LV) function and clinical course in transmural acute myocardial infarction (AMI), 38 patients were studied using a randomized, double-blind, placebo-controlled scheme. Nineteen patients received 1.0 million units of SK followed by 72 hours of heparin infusion and 19 received placebo followed by heparin infusion, all within 5 hours (mean 3.3 hours) after AMI onset. Patients ineligible for inclusion in the randomized trial were followed as a second, "historical control" group. Compared with placebo, SK caused a higher frequency of enzymatic evidence of reperfusion (6% vs 79%, p less than 0.001) and of patent infarct-related arteries at predischarge coronary arteriography (64% vs 88%, difference not significant). (Patients in the control group had a relatively low frequency of spontaneous thrombolysis--28%.) In the SK group LV ejection fraction increased from early (average 7.3 hours after AMI) to late (predischarge) study (from 40% early to 47% late, p less than 0.05); in the placebo group LV ejection fraction did not change significantly (from 41% to 42%). Predischarge exercise radionuclide ventriculography showed mild and similar degrees of inducible ischemia in both groups. After a mean of 12.8 months of follow-up, 1 SK patient and 4 placebo patients had died (difference not significant). In conclusion, intravenous SK is efficacious for thrombolysis in patients with AMI. It improves global LV function without augmenting exercise-inducible ischemia.

Mitral regurgitation: relationship of noninvasive descriptors of right and left ventricular performance to clinical and hemodynamic findings and to prognosis in medically and surgically treated patients

To determine objective predictors of survival, 53 patients with chronic, hemodynamically severe mitral regurgitation underwent rest and exercise radionuclide cineangiography, echocardiography, treadmill exercise testing, and ambulatory electrocardiographic monitoring before prospective (average 30 month) follow-up. At entry, symptom status correlated best with radionuclide-based right ventricular ejection fraction (RVEF) and left atrial size, while treadmill exercise tolerance correlated best with RVEF during exercise (r = .48, p less than .005). Correspondingly, in 23 patients who underwent cardiac catheterization, pulmonary arterial systolic and wedge pressures were significantly inversely related to RVEF. On the 24 hr ambulatory electrocardiogram, nonsustained ventricular tachycardia was present in 29% of patients, most frequently when both RVEF and left ventricular ejection fraction (LVEF) were subnormal (p = .03 vs other patients). Since entry, 35 patients have been managed without surgery for 9 to 57 months (average 28); three of these who subsequently underwent operation also are among the 21 patients who have undergone mitral valve replacement (MVR). During the average 28 months of observation under medical treatment five of 35 nonoperated patients have died; all five were among the six nonoperated patients with RVEFs of 30% or less at entry, a descriptor that significantly identified those at high mortality risk (p less than .0001 vs patients with RVEFs greater than 30%). All five also were among the eight nonoperated patients with LVEFs of 45% or less (lower limit of normal), a descriptor that also significantly predicted mortality. Three of the 21 patients who underwent surgery have died, all late after MVR. Among operated patients, only age was a predictor of postoperative survival. A trend toward improved survival was found in the patients with depressed right or left ventricular ejection fraction who underwent surgery compared with those who did not.

Left atrial myxoma: diagnosis by digital subtraction intravenous angiography

Digital subtraction intravenous angiography (DSIVA) represents an important technical advance in angiographic diagnosis. Herein we present three patients with left atrial myxoma assessed by DSIVA. We review the role of DSIVA in evaluation of patients with suspected cardiac tumors and the importance of careful atrial-phase scrutiny in examinations obtained for other purposes (ie, pulmonary angiography and assessment of ventricular function).

Increased cardiac performance in mild essential hypertension. Left ventricular mechanics

To analyze cardiovascular dynamics in essential hypertension, 81 subjects with untreated mild essential hypertension (mean blood pressure, 112 +/- 14 mm Hg) and 87 normotensive subjects from the same working population were studied by echocardiography and simultaneous blood pressure determination. Hypertensive subjects had significantly higher pulse pressure, stroke volume index, cardiac index, left ventricular internal dimension, end-systolic pressure/volume ratio, end-systolic stress, left ventricular mass index, and relative wall thickness than normotensive subjects. Among both normotensive and hypertensive subjects, cardiac performance was closely dependent on afterload, as indicated by close inverse linear relationships between left ventricular fractional shortening and log end-systolic stress (r = -0.83 and -0.78 respectively; both, p less than 0.001). However, 19 of 81 hypertensive patients (23%) fell above the 95% confidence limits of this relationship in normotensive subjects (p less than 0.001 compared with that in normotensive subjects), with a bimodal distribution of fractional shortening as a percent of predicted in relation to end-systolic stress among patients with essential hypertension. This subgroup of hypertensive subjects, with increased resting cardiac performance independent of afterload, was similar in age to the remaining hypertensive subjects but had higher fractional shortening (41 +/- 5% vs 35 +/- 7%; p less than 0.001) and cardiac index (4.3 +/- 1.3 L/min/m2 vs 3.4 +/- 1.0 L/min/m2; p less than 0.005) and lower total peripheral resistance (1257 +/- 502 dyn sec cm-5 vs 1582 +/- 584 dyn sec cm-5 p less than 0.05) and left ventricular relative wall thickness (0.34 +/- 0.06 vs 0.42 +/- 0.10; p less than 0.005). Thus, analysis of cardiac mechanics detected a subset of patients with essential hypertension in whom increased cardiac function cannot be attributed either to relative youth or to supercompensatory left ventricular hypertrophy.

Relation of hemoglobin A1 and blood glucose to cardiac function in diabetes mellitus

To examine the relation of short- and long-term changes in glucose metabolism to cardiac function, radionuclide cineangiography and echocardiography were performed in 10 young insulin-dependent diabetic patients without clinical evidence of heart disease. Cardiac assessments were performed before and after both acute variations in blood glucose, and induction of chronic "tight glucose control" involving normalization of hemoglobin A1 concentrations. In diabetic patients, left ventricular (LV) ejection fraction (EF) at normal blood glucose concentration was indistinguishable from values in 11 normal subjects. However, during hyperglycemia (about 300 mg/dl), the average EF at rest was 61%, significantly higher than that during normoglycemia (56%, p less than 0.001). No significant change in LV diastolic dimension was noted in association with shifts between high and normal blood glucose concentrations. Normalization of hemoglobin A1 was achieved within 6 to 25 weeks. This alteration had no significant effect on LVEF, mitral valve E-F slope, or the response of systolic function to blood glucose levels. In addition, no correlation was found between LVEF and hemoglobin A1 concentrations in 4 of 5 evaluation periods. Thus, in young insulin-dependent diabetic patients without overt heart disease, variation in blood glucose concentration is associated with small but significant variation in EF at rest; normalization of hemoglobin A1 has no significant effect on LVEF or the response of systolic function to blood glucose levels.

[Significance of the ejection fraction at rest and by stress using radionuclide ventriculography for the prognosis of myocardial infarct patients--comparison with other study methods]

We examined 221 patients with postmyocardial infarctions 8 weeks after MI using radionuclide ventriculography (RNVA) at rest (EFR) and during supine submaximal exercise (delta EF). Mortality rates were evaluated 2 1/2 and 3 1/2 years later by interviewing patients and/or their homephysicians. Sixteen patients were dead (6.7%) 2 1/2 years after MI, 28 (12.7%) were dead after 3 1/2 years. Thirty percent of patients with a resting EF less than 30% had died 2 1/2 years after MI, and 40% were dead within 3 1/2 years. The mortality rate was significantly higher than in patients who had EF greater than or equal to 30% 8 weeks after MI. Patients with a decrease of delta EF (greater than or equal to 5%) showed a 2 1/2 year mortality of 10.8% and after 3 1/2 years of 18.5%. Mortality was significantly higher in patients with decreasing EF during exercise than in those who increased their EF during exercise. This prognostic value of EFR and delta EF was compared with other parameters (angina pectoris, ECG at rest and during exercise, heart volume, Holter ECG, floating catheter PCP [rest and exercise], coronary angiography). Radionuclide ventriculography at rest and during exercise showed a tendency to be the best determining factor for prognosis, and is therefore recommended to determine prognosis in post-MI patients.

Correlation of the exercise ST/HR slope with anatomic and radionuclide cineangiographic findings in stable angina pectoris

A rate-related change in ST-segment depression with exercise (ST/HR slope) of 6.0 microV/beat/min or more has been proposed as an accurate predictor of 3-vessel coronary artery disease (CAD). To further assess the accuracy and functional correlates of this method, exercise electrocardiograms were compared with radionuclide rest and exercise left ventricular (LV) ejection fraction (EF) and angiography in 35 patients with stable angina. The ST/HR slope was significantly increased in patients with 3-vessel CAD. An ST/HR slope of 6.0 or more identified 3-vessel CAD with a sensitivity of 89% and specificity of 88%. The predictive value for 3-vessel CAD was 73% owing to the presence of 3 false-positive slopes. The patients from whom these slopes were derived had functionally severe 2-vessel CAD, with an average decrease in exercise LVEF of 13%. Two of these 3 had additional left main CAD and the third has unsuspected additional aortic regurgitation. For the entire group, the exercise ST/HR slope was linearly related to the exercise change in LVEF (r = -0.55, p less than 0.001). Mean exercise change in LVEF for stable angina patients with ST/HR slopes of 4.5 or more was significantly different from that for patients with lower ST/HR slopes (-12 +/- 1% vs + 2 +/- 2%, p less than 0.0001). Thus, the ST/HR slope is both sensitive and specific for the identification of 3-vessel CAD, and high ST/HR slopes in patients with less extensive anatomic disease may predict functionally severe ischemia.

Complex arrhythmias in mitral regurgitation with and without mitral valve prolapse: contrast to arrhythmias in mitral valve prolapse without mitral regurgitation

Atrial and ventricular arrhythmias were characterized by ambulatory electrocardiography in 31 patients with nonischemic mitral regurgitation (MR), 17 of whom had echocardiographic evidence of mitral valve prolapse (MVP) and 14 of whom had other causes of MR. Frequent and complex arrhythmias were common and equally prevalent in each MR subgroup, whether or not MVP was present. Multiform ventricular ectopy was found in 77% (24 of 31), ventricular couplets in 61% (19 of 31), and ventricular salvos or ventricular tachycardia in 35% (11 of 31) of patients with MR. Arrhythmias in patients with MR were significantly more prevalent than in 63 patients with MVP who had no evidence of MR. Among patients with MVP, excess arrhythmias associated with MR were most striking with respect to frequent ventricular premature complexes (41% with MR vs 3% without MR), multiform ventricular ectopic activity (88% vs 43%), ventricular couplets (65% vs 6%), and ventricular salvos or ventricular tachycardia (35% vs 5%) (p less than 0.005 for each comparison). These data demonstrate that complex arrhythmias are common in patients with nonischemic MR irrespective of etiology, and that these arrhythmias are more strongly associated with hemodynamically important MR than with MVP alone.

Predictive value and limitations of the ST/HR slope

To assess the value and predictive limitations of the exercise ST/HR slope, exercise test results were compared in 50 patients with stable angina and in 17 normal subjects with those in two groups known to have a high prevalence of inaccurate electrocardiographic responses to exercise. The last two groups included 51 patients tested within three weeks of acute myocardial infarction and 17 with important aortic regurgitation but no coronary disease. Of the normal subjects, 16 (94%) had ST/HR values less than or equal to 1 X 1 microV/beat/min. Of those with stable angina pectoris, 42 of 46 (91%) patients with coronary artery disease had ST/HR slopes ranging from 1 X 2 to 20 X 0 microV/beat/min, with false negative findings (slopes less than or equal to 1 X 1 microV/beat/min) in only four (9%). In contrast, of those with recent myocardial infarction, 15 of 42 (36%) with coronary disease had false negative slopes, including 12 of 20 (60%) with anterior wall injury. Of those with aortic regurgitation, conversely, 14 of 16 (88%) patients with calculable ST/HR slopes had values greater than 1 X 1 microV/beat/min despite the absence of coronary disease. Despite the accuracy of the test in patients with stable angina, false negative results are common in those after recent myocardial infarction, and false positive results occur often in those with abnormal volume loading due to aortic regurgitation.

Hemodynamic assessment of intravenous bepridil administration in ischemic heart disease

The hemodynamic effects of intravenous administration of bepridil were evaluated in 17 patients with chronic coronary artery disease who underwent cardiac catheterization. Of the 17 patients, 8 received bepridil, 2 mg/kg of body weight, for 15 minutes followed by 1 mg/kg for 15 minutes (group A), and 9 received 3 mg/kg followed by 1 mg/kg (group B). In group A, the systemic blood pressure (BP) decreased (p less than 0.05) and left ventricular end-diastolic pressure increased minimally (p less than 0.05). Heart rate (HR), pulmonary artery pressure, cardiac output (CO), stroke index, pulmonary vascular resistance and systemic vascular resistance (SVR), stroke work index, "contractility" (+dP/dt) and double product (HR X systolic BP) showed no significant change after bepridil infusion. In contrast, in group B, while +dP/dt decreased (p less than 0.01), SVR also showed a strong downward trend and changed significantly more than in group A; in the context of the latter alteration, CO increased significantly. In addition, the double product (less than 0.025) and systemic BP (p less than 0.05) decreased, though other parameters did not vary significantly. Thus, although a modest dose-related negative inotropic effect (decreased +dP/dt) was seen, dose-related direct systemic vasodilatation (decreased SVR) led to improved cardiac performance (increase in cardiac index) at the larger dose.

Improved accuracy of the exercise electrocardiogram: identification of three-vessel coronary disease in stable angina pectoris by analysis of peak rate-related changes in ST segments

Exercise electrocardiography has relatively poor specificity and predictive accuracy for 3-vessel coronary artery disease (CAD) when conventional diagnostic criteria are used. However, electrocardiographic evaluation using linear regression analysis of the heart-rate (HR)-related change in ST-segment depression (ST/HR slope) is reported to accurately distinguish patients with from those without CAD, and to accurately separate patients with 1-, 2- and 3-vessel CAD. To assess the applicability of this method and to compare it with conventional interpretation, retrospective evaluation of 50 patients in whom exercise electrocardiography and coronary cineangiography had been performed for suspected CAD was conducted using a modified ST/HR slope analysis limited to leads V5, V6 and aVF. Eighteen patients had 3-vessel, 22 had 2-vessel, 6 had 1-vessel and 4 had no CAD. Standard electrocardiographic criteria (1 mm or more of horizontal or downsloping ST depression) identified 3-vessel CAD with a sensitivity of 78%, specificity of 56% and positive predictive value of only 50%. Peak ST/HR slope criteria (greater than or equal to 6.0 microV/beat/min) identified 3-vessel CAD with a sensitivity of 78%, specificity of 97% and positive predictive value of 93%. The overall test accuracy using measured peak ST/HR slope was 90%, compared with 64% for standard ST-depression criteria. In conclusion, analysis of the peak ST/HR slope can greatly improve the diagnostic accuracy of exercise electrocardiography, and further prospective study of this method is indicated.

Effect of bepridil in patients with chronic stable angina: results of a multicenter trial

The effects of bepridil, a calcium antagonist with a half-life of approximately 42 hr, were assessed in a double-blind, randomized, placebo-controlled crossover trial. Forty-four patients (39 men, five women) with exercise-induced angina pectoris and ST segment depression with exercise testing (modified Bruce protocol) were studied. Compared with placebo bepridil (400 mg daily) increased total exercise time, time to onset of angina, time to 1 mm of ST segment depression, time to 2 mm of ST segment depression, and total work achieved (all p less than or equal to .001). Both frequency of angina and nitroglycerin consumption decreased during the bepridil compared with the placebo period (p = .02 and .03, respectively). Minor side effects were noted during both the bepridil and placebo phases. Four patients experienced side effects that limited therapy (dizziness in three and abnormal results of liver function tests in one) and one patient died during the bepridil phase. This study suggests that bepridil, 400 mg daily, is effective for the treatment of exercise-induced myocardial ischemia and angina pectoris.

Exercise-induced ischemia in mildly symptomatic patients with coronary-artery disease and preserved left ventricular function. Identification of subgroups at risk of death during medical therapy

To determine prospectively whether the severity of reversible left ventricular ischemia provides prognostic information in mildly symptomatic patients with coronary-artery disease and preserved left ventricular function at rest (ejection fraction greater than 40 per cent), we studied 117 patients by means of exercise electrocardiography and radionuclide angiography. No patient had stenosis of the left main coronary artery. Mortality during subsequent medical therapy was significantly associated (by univariate life-table analysis) with three-vessel coronary-artery disease and the magnitude of the ejection fraction during exercise. In patients with three-vessel disease who had both ST-segment depression of 1 mm or more and a decrease in ejection fraction during exercise, in association with an exercise tolerance of 120 W or less, the probability of survival at four years was only 71 +/- 11 per cent (S.E.). All deaths occurred in this subgroup. Thus, objective evidence of left ventricular ischemia during exercise and exercise capacity identify one subgroup of minimally symptomatic patients with three-vessel disease with an excellent prognosis and another subgroup at relatively high risk of dying during subsequent medical therapy.

Hemodynamic effects of nifedipine versus hydralazine in primary pulmonary hypertension

The acute hemodynamic effects of both sublingual nifedipine (N) and intravenous hydralazine (Hy) were studied in 5 patients with primary pulmonary hypertension to ascertain whether the capacity for pulmonary vasodilatation was generalized or drug-specific, and to determine which of the 2 agents had preferential pulmonary vasodilatory effects. For the group as a whole, neither N nor Hy produced changes in heart rate, mean pulmonary capillary wedge or right atrial pressures. Both N and Hy reduced mean systemic arterial pressure (before N 90 +/- 8 mm Hg, after N 76 +/- 7 mm Hg, p less than 0.01; before Hy 92 +/- 11 mm Hg, after Hy 68 +/- 8 mm Hg, p less than 0.05), and decreased systemic vascular resistance (before N 1,558 +/- 645 dynes s cm-5, after N 1,192 +/- 430 dynes s cm-5, p less than 0.05; before Hy 1,700 +/- 415 dynes s cm-5, after Hy 957 +/- 285 dynes s cm-5, p less than 0.05). In addition, N administration resulted in an increased cardiac output (before N 4.5 +/- 2.0 liters/min, after N 4.8 +/- 2.0 liters/min, p less than 0.01); Hy administration was associated with a more varied effect on cardiac output (before Hy 4.0 +/- 1.0 liters/min, after Hy 5.3 +/- 1.8 liters/min, p less than 0.10, difference not significant [NS]).(ABSTRACT TRUNCATED AT 250 WORDS)