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.     

Differentiation of septal from free wall accessory pathway location: observations during bundle branch block in reciprocating tachycardia in the presence of type I antiarrhythmic drugs

In patients with Wolff-Parkinson-White syndrome, observations during bundle branch block (BBB) in reciprocating tachycardia are of value in accessory pathway localization. Most importantly, an increase in the ventriculoatrial (VA) interval of greater than or equal to 35 ms has indicated an ipsilateral free wall location and excluded a septal location. The present study examined whether data collected in the presence of type I antiarrhythmic drugs retained localizing value. Review of retrospective data showed that observations in the drug-free state were precluded by the need to suppress atrial arrhythmia during electrophysiologic study in 20% of patients with Wolff-Parkinson-White syndrome who underwent preoperative workup. Prospectively, in 15 patients with left free wall or posteroseptal pathways, we observed transient left BBB during tachycardia before and after administration of procainamide, disopyramide or quinidine. Serum drug levels ranged from 4.6 to 6.9 mg/liter, except in 1 patient with a serum procainamide level of 18 mg/liter. Drugs increased the VA interval during narrow QRS tachycardia by 17% (p less than 0.01). However, the change in the VA interval with left BBB was not significantly affected. The baseline and drug values averaged 73 ms (range 39 to 94) and 70 ms (range 39 to 90), respectively, for left free wall pathways (n = 8), and 19 ms (range 0 to 28) and 21 ms (range 2 to 35), respectively, for posteroseptal pathways (n = 7). Among the latter, the interval increased less than 30 ms during left BBB except in the patient with the high serum procainamide level, in whom the increase was 35 ms. Thus, the VA interval change that accompanied left BBB remained of localizing value with moderate blood levels of type I drugs, and an increase greater than or equal to 35 ms indicated a left free wall rather than posteroseptal pathway.     

Clinical spectrum of ventricular tachycardia with left bundle branch morphology

Twenty-nine patients with apparent ventricular tachycardia (VT) of left bundle branch block (LBBB) morphology were evaluated. Tachycardia was associated with an organic basis in 24 of 29 patients: 7 had Mahaim fibers of the nodoventricular type, 7 had arrhythmogenic right ventricular dysplasia, 5 had coronary heart disease, 3 had biventricular cardiomyopathy, and 2 had associated congenital heart disease. In many patients the underlying cardiac disease was not readily apparent. In the patients with a Mahaim fiber, the electrocardiogram taken during sinus rhythm was frequently normal. A reentry tachycardia with anterograde conduction over the nodoventricular fiber could mimic VT as diagnosed by the usual criteria; nodoventricular fibers were, therefore, often unsuspected before electrophysiologic evaluation. In patients with arrhythmogenic right ventricular dysplasia, cineangiography demonstrated abnormalities of the right ventricle, but only minor or no abnormalities of the left ventricle. Clinical and electrocardiographic features were not distinctive. Of the 29 patients, 22 had serious symptoms accompanying the tachyarrhythmia or had required cardioversion. Patients were followed up for an average of 20 months: 4 patients died. Thus, VT exhibiting an LBBB morphology is not uncommon and is frequently associated with organic heart disease, serious symptoms, and significant mortality. Right ventricular angiography and electrophysiologic study may clarify the diagnosis in these patients.     

"Left main equivalent" coronary artery disease: its clinical presentation and prognostic significance with nonsurgical therapy

The clinical characteristics and nonsurgical prognosis of 55 patients with "left main (LM) equivalent" coronary artery disease (CAD) were evaluated and defined as: (1) greater than or equal to 75% diameter reduction of the left anterior descending coronary artery (LAD) before the takeoff of any large septal perforator or anterolateral (diagonal) branches; (2) greater than or equal to 75% diameter reduction of the left circumflex artery (LC) before the takeoff of any large marginal branch; and (3) absence of greater than or equal to 50% stenosis of the LM coronary artery. Compared with nonsurgically treated patients with greater than or equal to 75% stenosis of the LM artery, patients with LM equivalent CAD had a shorter duration of symptoms (median of 51 months vs 66 months) and more often had a Q wave on the electrocardiogram (60 vs 39%). Survival in patients with LM equivalent CAD (78% at 1 year and 55% at 5 years) was better than that in patients with LM disease with nonsurgical therapy (65% at 1 year and 40% at 5 years) (p = 0.02), although the rate of freedom from cardiovascular events was not significantly different. Compared with other nonsurgically treated patients with 2- or 3-vessel CAD involving the LAD and LC (28 and 42%, respectively, with progressive angina), patients with LM equivalent CAD had more severe anginal symptoms (55% with progressive angina) and a longer duration of symptoms (medians of 20 months in 2-vessel CAD, 36 months in 3-vessel CAD and 51 months in LM equivalent CAD).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

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.     

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.     

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.     

Exercise responses before and after physical conditioning in patients with severely depressed left ventricular function

The ability of patients with severely impaired left ventricular function to perform short-term exercise and to participate in a cardiac rehabilitation program and attain physical training effects was evaluated. Treadmill exercise tests were performed before and after physical conditioning in 10 patients with a prior myocardial infarction and a left ventricular ejection fraction at rest of less than 27 percent (range 13 to 26) determined by radionuclide angiography. All patients participated in a supervised exercise program with a follow-up period of 4 to 37 (mean 12.7) months. Baseline exercise capacity showed marked variability, ranging from 4.5 to 9.4 (mean 7.0 ± 1.9) METS, and improved to 5.5 to 14 (mean 8.5 ± 2.9) METS after conditioning (p = 0.05). The oxygen pulse (maximal oxygen uptake/maximal heart rate) before and after conditioning was used to assess a training effect and increased significantly from 12.8 ± 2.0 to 15.7 ± 3.2 ml/beat (p < 0.01). There was no exercise-related morbidity or mortality, although two patients died during the study period. It is concluded that selected patients with severely impaired left ventricular function can safely participate in a conditioning program and achieve cardiovascular training effects.     

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.     

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.     

Effects of exercise training on left ventricular function in normal subjects: A longitudinal study by radionuclide angiography

Radionuclide angiocardiography provides accurate hemodynamic information during maximal exercise in erect subjects. Cardiac function was studied with this noninvasive technique in 12 male and 6 female college athletes before (BT) and after (AT) 6 months of swimming training. Measurements at rest and during maximal exercise of heart rate, left ventricular ejection fraction, end-diastolic volume, cardiac output and total body blood volume were determined from first pass and equilibrium precordial counting techniques. The results were as follows:

     

15.

Cardiac function during rest and exercise in patients with mitral valve prolapse: Role of radionuclear angiocardiography     

Glenn E. Newman  Raymond J. Gibbons  Robert H. Jones 《The American journal of cardiology》1981,47(1):14-19

The clinical features of mitral valve prolapse syndrome and ischemic coronary disease overlap, making differentiation of the two conditions difficult. Furthermore, many patients have both conditions. This study assessed changes in ventricular function during rest and exercise in patients with mitral valve prolapse alone and in patients with prolapse and concomitant coronary artery disease. Twelve patients with angiographically documented mitral valve prolapse and normal coronary anatomy and 11 patients with normal coronary anatomy and no mitral valve prolapse had increased ejection fraction and demonstrated no wall motion abnormality during exercise. Changes in ventricular function during exercise in 11 additional patients with mitral valve prolapse demonstrated on echocardiography were similar to those in the group with mitral valve prolapse and normal coronary anatomy seen on angiography. In contrast, 6 of 11 patients with mitral valve prolapse and coronary arterial stenosis demonstrated on angiography had a decreased ejection fraction and exhibited wall motion abnormalities during exercise. These results suggest that mitral valve prolapse alone has no detrimental effect on ventricular function during rest and exercise and that exercise-induced abnormalities in ventricular function are related to the presence and severity of coronary artery disease and not to mitral valve prolapse.     

16.

Transvenous ablation of the atrioventricular conduction system in dogs: Electrophysiologic and histologic observations     

Gust H. Bardy MD  Raymond E. Ideker MD  PhD  Jack Kasell  Seth J. Worley MD  William M. Smith PhD  Lawrence D. German MD  John J. Gallagher MD   《The American journal of cardiology》1983,51(10):1775-1782

The correlation of histologic and electrophysiologic findings in dogs undergoing transvenous ablation of atrioventricular (AV) conduction has not been described. The creation of complete AV block in 10 dogs was attempted by delivering a direct-current shock transvenously through a standard tripolar electrode catheter. The catheter was positioned to record the largest unipolar atrial and His bundle electrograms. A 280 J shock was delivered to the recording electrode by a standard cardioversion unit. After 1 shock, all dogs were in complete AV block refractory to isoproterenol (1 to 4 μg/min) and atropine (0.5 to 2.0 mg). Four weeks later, 5 dogs remained in complete AV block, 1 had first-degree block, and 4 had resumed normal AV conduction. Each dog with complete heart block had histologic evidence of severe damage to the AV node, His bundle, or both. On gross examination, these dogs were found to have discrete scars at the base of the septal leaflet of the tricuspid valve. Of the 5 dogs that had resumption of AV conduction, only 1 had histologic evidence of significant damage to the AV conduction system. That animal manifested a marked increase in the P-R interval (100 to 210 ms). Although temporary heart block occurred in each animal, chronic interruption of AV conduction was more difficult. Catheter location, atrial and His bundle electrogram relations, and the electrode used for delivery of energy were factors determining the effectiveness of this technique.     

17.

Evaluation of a QRS scoring system for estimating myocardial infarct size: III. Correlation with quantitative anatomic findings for inferior infarcts     

Steven F. Roark  Raymond E. Ideker  Galen S. Wagner  Daniel R. Alonso  Sanford P. Bishop  Colin M. Bloor  Dean A. Bramlet  Jesse E. Edwards  John T. Fallon  Geoffery J. Gottlieb  Donald B. Hackel  Harry R. Phillips  Keith A. Reimer  William J. Rogers  Wayne K. Ruth  Robert M. Savage  Richard D. White  Ronald H. Selvester 《The American journal of cardiology》1983,51(3):382-389

     

18.

Localization of septal pacing sites in the dog heart by epicardial mapping     

Warren M. Smith  Raymond E. Ideker  William M. Smith  Jack Kasell  Lura Harrison  Gust H. Bardy  John J. Gallagher  Andrew G. Wallace 《Journal of the American College of Cardiology》1983,1(6):1423-1434

     

19.

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

Richard D. Floyd  Galen S. Wagner  Erle H. Austin  David C. Sabiston  Robert H. Jones 《The American journal of cardiology》1983,52(8):943-949

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.     

20.

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

Erle H. Austin MD  Frederick R. Cobb MD  R.Edward Coleman MD  Robert H. Jones MD 《The American journal of cardiology》1982,50(6):1212-1216

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.     

	Heart Rate (beats/ min)	Ejection Fraction (%)	End-Diastolic Volume (ml)	Cardiac Output (liters/ min)	Total Body Blood Volume (liter)
Rest
BT	$\text{74 ± 11}$	$\text{73 ± 6}$	$\text{133 ± 35}$	$\text{6.9 ± 1.1}$	$\text{8.7 ± 0.8}$
AT	$\text{61 ± 7}$	$\text{67 ± 7}$	$\text{167 ± 40}$	$\text{6.7 ± 1.0}$	$\text{11.4 ± 2.2}$
Exercise
BT	$\text{185 ± 10}$	$\text{87 ± 4}$	$\text{166 ± 34}$	$\text{25.5 ± 5.7}$	$\text{8.0 ± 0.9}$
AT	$\text{181 ± 14}$	$\text{86 ± 5}$	$\text{204 ± 39}$	$\text{32.0 ± 8.7}$	$\text{10.8 ± 2.3}$

Cardiac function during rest and exercise in patients with mitral valve prolapse: Role of radionuclear angiocardiography

The clinical features of mitral valve prolapse syndrome and ischemic coronary disease overlap, making differentiation of the two conditions difficult. Furthermore, many patients have both conditions. This study assessed changes in ventricular function during rest and exercise in patients with mitral valve prolapse alone and in patients with prolapse and concomitant coronary artery disease. Twelve patients with angiographically documented mitral valve prolapse and normal coronary anatomy and 11 patients with normal coronary anatomy and no mitral valve prolapse had increased ejection fraction and demonstrated no wall motion abnormality during exercise. Changes in ventricular function during exercise in 11 additional patients with mitral valve prolapse demonstrated on echocardiography were similar to those in the group with mitral valve prolapse and normal coronary anatomy seen on angiography. In contrast, 6 of 11 patients with mitral valve prolapse and coronary arterial stenosis demonstrated on angiography had a decreased ejection fraction and exhibited wall motion abnormalities during exercise. These results suggest that mitral valve prolapse alone has no detrimental effect on ventricular function during rest and exercise and that exercise-induced abnormalities in ventricular function are related to the presence and severity of coronary artery disease and not to mitral valve prolapse.     

Transvenous ablation of the atrioventricular conduction system in dogs: Electrophysiologic and histologic observations

The correlation of histologic and electrophysiologic findings in dogs undergoing transvenous ablation of atrioventricular (AV) conduction has not been described. The creation of complete AV block in 10 dogs was attempted by delivering a direct-current shock transvenously through a standard tripolar electrode catheter. The catheter was positioned to record the largest unipolar atrial and His bundle electrograms. A 280 J shock was delivered to the recording electrode by a standard cardioversion unit. After 1 shock, all dogs were in complete AV block refractory to isoproterenol (1 to 4 μg/min) and atropine (0.5 to 2.0 mg). Four weeks later, 5 dogs remained in complete AV block, 1 had first-degree block, and 4 had resumed normal AV conduction. Each dog with complete heart block had histologic evidence of severe damage to the AV node, His bundle, or both. On gross examination, these dogs were found to have discrete scars at the base of the septal leaflet of the tricuspid valve. Of the 5 dogs that had resumption of AV conduction, only 1 had histologic evidence of significant damage to the AV conduction system. That animal manifested a marked increase in the P-R interval (100 to 210 ms). Although temporary heart block occurred in each animal, chronic interruption of AV conduction was more difficult. Catheter location, atrial and His bundle electrogram relations, and the electrode used for delivery of energy were factors determining the effectiveness of this technique.     

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.     

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.