Nonfatal myocardial infarction in medically treated patients with coronary artery disease

The purpose of this study was to identify patient characteristics associated with nonfatal myocardial infarction as the first event after cardiac catheterization in medically treated patients with coronary artery disease. Multiple logistic risk analyste of 81 baseline characteristics in 354 patients who died or had nonfatal infarction identified 10 characteristics (5 clinical and 5 cardiac catheterization variables) as independently discriminating between the two events. Left ventricular function, specific coronary anatomy, previous myocardial infarction and age were the most important discriminators. Poor left ventricular function and left main coronary stenosis were associated with death. Subtotal left anterior descending and right coronary arterial stenosis, normal hemodynamics, absence of previous infarction and young age were associated with nonfatal infarction. Thus, in any subset of patients who have a uniform risk of ischemic events (nonfatal infarction or death), nonfatal infarction is most likely to occur in those who are young, have had no previous infarction, have subtotal left anterior descending and right coronary arterial stenosis and normal hemodynamics.     

An improving prognosis over time in medically treated patients with coronary artery disease

The national mortality rate from coronary heart disease has decreased during the past decade, for reasons that are not yet clear. The mortality rate and the total number of cardiovascular events both decreased during the last 10 years in 1,911 medically treated patients with significant coronary artery disease. This decrease cannot be explained by less sick patients being referred for evaluation. This study suggests that at least part of the decrease in coronary heart disease mortality observed nationally is occurring in patients with established coronary disease.     

Prospective evaluation of radionuclide angiocardiography for the diagnosis of coronary artery disease

This investigation assesses prospectively the accuracy of rest and exercise radionuclide angiocardiography (RNA) in detecting coronary artery disease (CAD). By retrospective analysis of 496 patients, optimal RNA criteria were determined for the presence or absence of CAD. Multivariate analysis of patients with normal coronary arteries on catheterization provided a formula to predict normal exercise ejection fraction (EF) in a given patient. The presence of CAD was indicated by 1 or more of the following RNA measurements: (1) rest EF < 0.50, (2) exercise EF at least 0.06 less than the predicted value, (3) exercise increase in end-systolic volume > 20 ml, (4) exercise-induced wall motion abnormality. The absence of CAD was indicated by the absence of all 4 criteria. After applying these criteria to 221 consecutive patients, the RNA determinations were compared with the catheterization determinations. Significant CAD was present in 71 % of the patients studied. The sensitivity of the test was 0.87 and the specificity 0.54. Thus, because of its high sensitivity, RNA is of value in screening patients under consideration for cardiac catheterization. No patient with significant left main coronary narrowing and only 4 of 65 patients with 3-vessel disease were misdiagnosed. The poor specificity of the test, however, limits its overall accuracy.     

Prognostic implications of ventricular arrhythmias during 24 hour ambulatory monitoring in patients undergoing cardiac catheterization for coronary artery disease

The prognostic importance of ventricular arrhythmias detected during 24 hour ambulatory monitoring was evaluated in 395 patients with and 260 patients without significant coronary artery disease. Ventricular arrhythmias were found to be strongly related to abnormal left ventricular function. A modification of the Lown grading system (ventricular arrhythmia score) was the most useful scheme for classifying ventricular arrhythmias according to prognostic importance. When only noninvasive characteristics were considered, the score contributed independent prognostic information, and the complexity of ventricular arrhythmias as measured by this score was inversely related to survival. However, when invasive measurements were included, the ventricular arrhythmia score did not contribute independent prognostic information. Furthermore, ejection fraction was more useful than the ventricular arrhythmia score in identifying patients at high risk of sudden death.     

Assessment of the use of the age- and sex-specific United States population as a control group for analysis of survival in coronary artery disease

The use of the age- and sex-specific U.S. population as a control group for analysis of survival in coronary artery disease was assessed. Population-based survival rates were calculated for nonsurgically treated patients evaluated for coronary artery disease at Duke University Medical Center. Survival of the overall group of medically treated patients with significant coronary artery disease was lower than the corresponding age- and sex-specific U.S. population rates. However, survival of patients with significant disease who had normal left ventricular contraction and stable chest pain was similar to the age- and sex-specific population survival rates. Both the observed survival and the population-based survival estimates for patients with normal left ventricular contraction and stable pain were lower than the survival of patients with normal coronary arteriograms. Even after deaths from ischemic heart disease are eliminated from the population rates, survival of patients with normal coronary arteries exceeded the age- and sex-specific population survival. Because of biases inherent in the selection of patients for cardiac catheterization and the presence of other serious diseases in persons in the general population, the age- and sex-specific U.S. population is not an adequate control group for rigorous analysis of the effect of therapy in coronary artery disease.     

Natural history of patients with single-vessel disease suitable for percutaneous transluminal coronary angioplasty

To permit comparison of percutaneous transluminal coronary angioplasty (PTCA) with conventional therapy, the clinical outcome was established in patients who would have been suitable candidates for PTCA but who presented before the technique was available. Coronary angiograms were reviewed of patients who met the following criteria: single-vessel disease with proximal subtotal coronary stenosis, chest pain of at least class II, and cardiac catheterization before 1981. Angiograms were evaluated according to established criteria for PTCA by an experienced angiographer. One hundred ten patients (2.1% of the patient population) were judged suitable for PTCA. Clinical and catheterization findings closely resembled those of patients in the national PTCA registry. Five years after catheterization, 97% of PTCA candidates treated medically were alive and 85% had not had myocardial infarction. Forty-six patients had coronary artery bypass surgery within 6 months of catheterization and 10 other patients had subsequent surgery. Five years after surgery, 91% were alive and 87% had not had myocardial infarction. At 6 months of follow-up, 78% of all patients had improved at least 1 functional class, and 86% of all patients working before catheterization were still employed. Functional capacity was well maintained during long-term follow-up (median 6.5 years, range 1.4 to 12.2). These data indicate that PTCA candidates have an excellent prognosis for survival, a low risk of infarction, and well-maintained functional capacity when revascularization is reserved for those with inadequate control of symptoms by medical therapy.     

Left bundle branch block: angiographic segmental wall motion abnormalities.

Ventricular wall motion as studied with contrast ventriculography has been judged normal in the few previously reported cases of patients with left bundle branch block who have neither coronary artery disease nor diffuse cardiomyopathy. However, recent echocardiographic studies have demonstrated a high frequency of segmental asynergy of the septal wall in such patients. In this study left ventricular wall motion was analyzed in 15 patients with left bundle branch block and without significant coronary artery disease or diffuse cardiomyopathy. Biplane cineangiograms from these patients were compared with those from 100 consecutive patients with normal intraventricular conduction and without coronary artery disease or cardiomyopathy using two techniques: qualitative visual inspection and a computer-assisted quantitative method. By qualitative review, 6 of 15 patients with left bundle branch block had regional akinesia or dyskinesia as compared with none of 100 patients with normal intraventricular conduction (chi square = 42.3; P less than 0.001). By quantitative review, 10 of 12 patients with left bundle branch block had abnormal wall motion along at least one hemiaxis. It is concluded that angiographic regional wall motion abnormalities are common in patients with left bundle branch block, even in the absence of coronary artery disease or diffuse cardiomyopathy. The abnormalities may result from the abnormal sequence of ventricular activation rather than from myocardial fibrosis.     

Hemodynamics at rest and during exercise after oral hydralazine in patients with cor pulmonale

Oral hydralazine has been shown to be effective in decreasing pulmonary arteriolar resistance and increasing cardiac output in some patients with primary pulmonary hypertension. To determine whether a similar response could be observed in patients with chronic cor pulmonale, the hemodynamic status before and after the oral administration of hydralazine (25 mg, then 50 mg every 6 hours for 48 hours) were evaluated in 12 patients at rest and in 8 during upright exercise. After hydralazine, there was an increase in cardiac output at rest, from 4.3 to 6.3 liters/min (p <0.001), and reductions in arterlovenous oxygen difference, from 8.1 to 6.1 volume percent (p <0.001), mean pulmonary arterial pressure, from 52 to 44 mm Hg (p <0.01), and pulmonary arteriolar resistance, from 11.2 to 6.2 units (p <0.0005). Similar hemodynamic changes occurred during exercise, including an increase in pulmonary arterial saturation from 27 to 39 percent (p <0.001) and a decrease in total pulmonary resistance from 12.7 to 8.9 units (p <0.01). Results of pulmonary function tests performed before and after hydralazine did not change with drug administration. These findings indicate that the lung vascular bed in some patients with cor pulmonale is capable of responding to hydralazine with a reduction in pulmonary resistance and an increase in cardiac output both at rest and during exercise.     

Relation between QRS changes and left ventricular function after coronary artery bypass grafting

Preoperative and serial postoperative electrocar-diograms (ECGs) were reviewed in 104 patients undergoing rest and exercise radionuclide angiocardiography before and 1 to 12 months after coronary artery bypass grafting (CABG). Five patient groups were defined by ECG findings before and after CABG: Group I—normal ECG before and no ECG change after CABG; Group II—prior myocardial infarction by ECG before but no QRS change after CABG; Group III—all patients with a minor QRS change (< 0.04-second Q wave, loss of R-wave amplitude) after CABG; Group IV—all patients with a major QRS change (≥ 0.04-second Q wave) after CABG; Group V—all patients without new Q waves or loss of R-wave amplitude but with a major QRS change (conduction disturbance) after CABG. Mean resting ejection fraction changed little after CABG in all groups, although the 0.03 increase in Group I was significant (p < 0.05). Group IV had the largest decrease in resting ejection fraction after CABG (0.04), but this was not statistically significant. Mean exercise ejection fraction increased significantly (p < 0.0001) in Groups I, II and III but not in Groups IV and V. QRS changes do not consistently reflect impairment of left ventricular (LV) function after CABG.     

Subvalvular left ventricular pseudoaneurysm after mitral valve replacement: two-dimensional echocardiographic findings

Disruption of the posterior mitral anulus is a rare complication of mitral valve replacement that may result in subvalvular left ventricular pseudoaneurysm formation. Such pseudoaneurysm formation was easily recognized by two-dimensional echocardiography in a 54 year old man 3 years after his second mitral valve replacement. The finding was confirmed by cineangiography and direct surgical inspection. Recognition of this rare complication of mitral valve replacement has therapeutic importance because surgical correction is necessary.     

Ventricular tachycardia induced by atrial stimulation in patients without symptomatic cardiac disease

Ten patients with an unusual form of ventricular tachycardia (VT) are described. All were young (mean age 21 years) at the onset of VT, symptoms were of long duration (mean 7 years), none had symptomatic organic heart disease, VT was induced by atrial and ventricular stimulation, VT had a characteristic QRS morphologic picture resembling right bundle branch block with left-axis deviation and 9 had early retrograde His deflections during VT. Supraventricular tachycardia (SVT) was excluded in every patient by electrophysiologic study, although QRS morphologic characteristics and clinical stability of these patients during tachycardia frequently led to the diagnosis of SVT before referral. Four patients received verapamil during electrophysiologic testing. Verapamil slowed and terminated VT in all. Three patients are being treated chronically with oral verapamil, 3 patients with conventional antiarrhythmic agents and 1 with a radiofrequency ventricular pacemaker.     

Surgical treatment of arrhythmias: current status and future directions.

A variety of surgical interventions have evolved for the treatment of intractable or life-threatening arrhythmias unresponsive to conventional pharmacologic or pacemaker therapy. Supraventricular arrhythmias associated with rapid ventricular responses can be indirectly treated with ablation of the atrioventricular conduction system and insertion of a pacemaker. Ventricular tachyarrhythmias have previously been treated with sympathectomy, resection of tissue or revascularization. More recent approaches include the simple ventriculotomy, encircling endocardial ventriculotomy, cryosurgical ablation and insertion of the automatic implantable defibrillator. Refinement of methods to localize more precisely the origin of ventricular arrhythmias may allow design of more direct surgical procedures. The surgical treatment of arrhythmias related to the preexcitation syndromes remains the model of electrophysiologic surgery. It is now feasible to divide accessory pathways with a high degree of success and at low risk in selected patients.     

Ultrasound diagnosis of pseudoaneurysm and contiguous ventricular septal defect complicating inferior myocardial infarction

Two patients with recent inferior myocardial infarction were found by two-dimensional and Doppler echocardiography to have both an inferior wall pseudoaneurysm and a contiguous rupture of the posterior ventricular septum. The pseudoaneurysm was not suspected clinically in either patient. In one patient, a complex or dissecting septal rupture was visualized in detail. To our knowledge, the combined defect has not previously been diagnosed during life by noninvasive methods.     

Effects of exercise and isoproterenol during atrial fibrillation in patients with wolff-parkinson-white syndrome

The effects of exercise and isoproterenol on atrial fibrillation (AF) were studied in 17 patients with Wolff-Parkinson-White syndrome (WPW) to assess the risk of developing a rapid ventricular response. Mean cycle length (R-R interval) and shortest R-R interval between both preexcited and nonpreexcited QRS complexes were recorded, as well as the percentage of preexcited complexes during control periods, during bicycle exercise, and during isoproterenol infusion. Exercise resulted in significantly shorter mean cycle length and the shortest R-R interval between nonpreexcited complexes. Exercise also resulted in a significantly lower percentage of preexcited complexes during AF, but had no effect on the R-R intervals between preexcited complexes. Isoproterenol had a variable effect on the percentage of preexcited QRS complexes, but resulted in significant shortening of mean cycle length and the shortest R-R interval between both normal and preexcited complexes. With isoproterenol, 12 of 17 patients had shortest preexcited R-R intervals ≤215 ms, compared with 6 of 17 in the control state. Isoproterenol infusion increased the rate of conduction over the accessory pathway during AF and allowed better assessment of the risk of excessively rapid rates occurring during AF. Exercise is not an adequate test for this purpose.     

Ischemic cardiomyopathy: the myopathy of coronary artery disease. Natural history and results of medical versus surgical treatment

Clinical, hemodynamic and angiographic data were analyzed in 66 patients with coronary artery disease and severe generalized left ventricular dysfunction (ischemic cardiomyopathy) in order to determine their prognosis and examine the results of medical and surgical management. Seventy-six percent of patients had angina, 85 percent a history of one or more myocardial infarctions, 73 percent cardiomegaly, 38 percent mitral regurgitation, 98 percent severe stenosis of two or three major coronary arteries, and 100 percent a left ventricular ejection fraction of 25 percent or less.Forty-two patients were managed medically, and 24 surgically with aortocoronary bypass grafts or ventricular plication, or both. The clinical and hemodynamic findings in both groups were nearly identical. In a follow-up period of 12 months, the mortality rate was 31 percent in the medical group and 50 percent in the surgical group, with 83 percent of the surgical deaths occurring within 1 month of operation. There was no significant difference in the functional status of medical and surgical survivors. Regardless of therapy, patients with mitral regurgitation or a left ventricular end-diastolic pressure of 24 mm Hg or greater had a significantly higher mortality rate than patients without these findings. This study indicates that patients with ischemic cardiomyopathy have a poor prognosis, and surgical intervention with current available techniques has a high operative mortality rate without significantly altering the symptoms in the survivors.     

Myocardial depression by anesthetic agents (halothane, enflurane and nitrous oxide): quantitation based on end-systolic pressure-dimension relations

The end-systolic pressure-diameter relation of the left ventricle was used to examine the effect of halothane, enflurane and nitrous oxide on left ventricular (LV) contractility in 10 dogs chronically instrumented with dimension transducers to measure LV diameter and micromanometers to measure LV transmural pressure. Contractility was assessed by the slope (EES) of the end-systolic pressure-diameter relation. A new index that identifies the dose of anesthetic necessary to depress the inotropic state by 20% (ID20) was calculated to be 0.63% for halothane and 1.55% for enflurane, indicating a greater apparent myocardial depressant effect of halothane than enflurane. However, when these agents were compared at equi-anesthetic concentrations by normalizing the ID20 to the minimal alveolar concentration of each drug, they had comparable degrees of myocardial depressant effects. This measurement technique was used in 7 patients undergoing coronary artery bypass grafting conducted under narcotic anesthesia showing that halothane induced a similar depression of contractility. The use of ID20 should allow reclassification of anesthetic agents according to their myocardial depressant effects.