Pacemaker pseudodysfunction with a coronary sinus pacemaker

A permanent transvenous coronary sinus pacemaker functioned effectively for 22 months both as an atrial and ventricular pacemaker. Slow atrial flutter resulted in failure of the pacemaker to capture the myocardium and thus incorrectly suggested pacemaker dysfunction. Transtelephonic evaluation of this phenomenon was particularly difficult and could have resulted in unnecessary replacement of the pacing unit     

Vectorcardiographic changes following coronary artery bypass surgery

Myocardial infarction (MI) has been reported to occur in about 15 per cent of patients following coronary artery bypass (CAB) surgery. Preoperative and postoperative electrocardiograms (ECG) were evaluated in 85 patients. Thirty-four of these patients also had pre- and postoperative vectorcardiograms (VCG). Fifteen additional patients undergoing open heart surgery were used as controls. These included aortic valve replacement (in 4), mitral valve commissurotomy (in 6), mitral valve replacement (in 1), atrial septal defect repair (in 3), and repair SVC to LA shunt (in 1). Pre- and postoperative VCG's were analyzed in three planes. The angle of each 10 msec. vector was measured. The maximal voltage was determined along each axis in each plane. Mean changes in these parameters were determined for the controls. Change exceeding two standard deviations from the control mean was considered abnormal and not explainable by trauma of open heart surgery itself. Excluding the six intraoperative deaths, $\text{19}\text{79}$ (24 per cent) had QRS changes of myocardial infarction by ECG. Changes were considered significant in the postoperative VCG if they occurred in at least two consecutive angles in one plane or in the maximum voltage in one axis. The postoperative VCG depicted MI in 34 per cent ($\text{12}\text{34}$). In the absence of classic criteria for MI a significant change in VCG angle occurred in 26.4 per cent ($\text{9}\text{34}$). The voltage in at least one axis changed significantly in 11.8 per cent ($\text{4}\text{34}$). A change in the postoperative VCG was demonstrated in 73.5 per cent ($\text{25}\text{34}$). The pre- and postoperative VCG is a sensitive method of detecting subtle changes in conduction or loss of myocardium seen in the majority of patients following CAB surgery.     

Perioperative myocardial infarction related to coronary bypass surgery.

Frank lead electrocardiograms were recorded from 149 normal and abnormal adult males using four different electrode placements. All chest electrodes were placed at: (1) the fourth intercostal space level, (2) the fifth intercostal space level, (3) the fourth intercostal space level with V₄ substituted for C, and (4) the fifth intercostal space level with V₄ substituted for C.Differences in mean values of many commonly used amplitudes and orientations were not statistically significant among the four recording methods, but amplitude differences for individual subjects were often large and difficult to predict. When V₄ is substituted for C, as commonly done in some laboratories, R_x decreased and R_z increased by more than 10 per cent in about 40 per cent of the cases. In about 70 per cent of the cases, R_x and R_z changed significantly when electrode level was shifted from the fifth to the fourth intercostal space. For these 70 per cent, it does not appear possible to accurately predict increase or decrease of R_x, R_z, or QRS_m.Analysis programs which depend on individual amplitude measurements are likely to be significantly affected by electrode placement. It is suggested that criteria for analysis programs developed using a specified version of the Frank system should ideally be applied only to electrocardiograms recorded in the same manner.     

Cardiac rehabilitation following coronary artery bypass surgery

Early expectations of coronary revascularization prolonging life and reducing coronary events have been modified by 15 years' experience to mostly initial palliation of ischemic symptoms. Bypass surgery represents only a single therapeutic aspect for coronary atherosclerosis. Technically successful operations often fail miserably without overall risk factor alteration and functional capacity optimization which progressive exercise initiates during the postoperative period. Regular activity program participation improves physical conditioning, raises the symptom-limited exertional level, lessens post surgical musculoskeletal discomfort, and improves morale. Yet exercise alone without comprehensive secondary prevention and risk factor modification will be no more successful at arresting atherosclerosis than any other single measure. Both operative intervention and vigorous exertion are valuable components of coronary artery disease therapy, but must be part of an all-embracing effort. Whether regular exertion combined with overall risk factor modification will prolong life and reduce future cardiac events or beneficially alter the process of atherogenesis remain areas of avid investigation.     

A paucity of chronic electrocardiographic changes with adriamycin therapy

Serial electrocardiograms (ECGs) of 49 patients receiving adriamycin were analyzed for the development of persistent changes. The ECG changes were compared with those of a control group of 20 patients receiving other chemotherapeutic drugs, which were comparable to the additional chemotherapy received by the adriamycin patients. The only chronic ECG changes noted with adriamycin over control were the loss of P wave amplitude in the greater than 500 mg/m2 dose subgroup and the clockwise rotation of the precordial QRS in the 250-500 mg/m2 dose subgroup. In contrast, systolic time intervals demonstrated a gradual diminution in left ventricular function at increasing doses of adriamycin. The electrocardiogram itself appears to be of limited value in the assessment of cardiac toxicity with adriamycin therapy.     

The effect of coronary bypass surgery on exercise-induced ventricular arrhythmias.

Ninety-one patients with angiographically proved coronary artery disease and stable angina were randomly assigned into surgical and medical therapy. Graded exercise tests were performed on entry into the study and repeated in 1 year. Ventricular arrhythmias during exercise and 8 minutes of recovery were studied. Arrhythmias were graded on a scale of 0 to 7 by their presumed severity. On entry, both groups were similar in the severity of coronary disease, exercise capacity, and frequency and severity of exercise-induced ventricular arrhythmias. At 1 year, the frequency and severity of arrhythmias remained unchanged in both groups, whereas the surgically treated patients showed a marked improvement in their exercise capacity (p less than 0.005). The medically treated patients had a slight deterioration in their work capacity which, however, did not achieve statistical significance (p = 0.08). Twelve patients died suddenly. In seven medically treated patients who died suddenly, the frequency and severity of ventricular arrythmias on exercise were not different from those of the rest of the medical patients. In the five surgically treated patients who died suddenly, one had multiform premature ventricular beats, a second developed ventricular fibrillation (2 years before dying suddenly), and a third had no arrhythmias during exercise. Two died before the 1 year evaluation. Successful coronary surgery improves exercise capacity without decreasing associated ventricular arrhythmias. Exercise-induced ventricular arrhythmias, with the exception of ventricular fibrillation, may not be closely associated with the risk of sudden death.     

Serial exercise testing after coronary artery bypass surgery

To determine the duration of functional benefit from coronary bypass surgery, 111 patients with angina pectoris were serially evaluated by standard exercise testing prior to and for up to 4 years after surgery. Exercise testing 6 to 18 months after surgery showed greater heart rate-blood pressure product at peak work load, improved work capacity, and less symptomatic and electrocardiographic evidence of ischemia than was demonstrated preoperalively. Twenty patients were tested 37 to 48 months postoperatively and showed improved exercise performance in comparison with preoperative results, but the frequency of positive tests during this period no longer differed. Thus, improved exercise performance appears to persist for at least 4 years after coronary bypass surgery.     

Functional significance of electrocardiographic changes after left ventricular aneurysmectomy.

Electrocardiographic (ECG) changes after left ventricular aneurysmectomy were analyzed in 20 patients, thirteen of whom had additional aorto coronary saphenous vein bypass surgery. ECG changes were correlated with postoperative clinical and hemodynamic results. Out of 14 patients (Group I) who showed hemodynamic and/or clinical improvement, eight had decrease of chronic ST segment elevation that was associated in five with loss of pathologic Q waves. In the remaining six patients (Group II) who showed no hemodynamic or clinical improvement as well as in six patients in Group I, chronic ST segment elevation persisted or increased and in some, new pathologic Q waves developed after surgery. The study suggests that loss of pathologic Q waves and/or decrease of chronic ST segment elevation in patients who undergo a left ventricular aneurysmectomy with aorto coronary saphenous vein bypass surgery may reflect postoperative clinical, hemodynamic and angiographic improvement. On the other hand, failure of these ECG changes to occur or, conversely, increased ST segment elevation and/or appearance of new Q waves may have no predictive value. The mechanisms for these ECG changes are discussed.     

Angina pectoris and coronary bypass surgery: Patterns of prevalence and recurrence in 3105 consecutive patients followed up to 11 years

Many studies document the effectiveness of bypass surgery in relieving angina pectoris. Few, however, have described patterns of prevalence preoperatively and recurrence postoperatively. After excluding those known to be dead and those residing outside the continental United States, we attempted to contact all patients who had undergone first bypass surgery by us. Follow-up was 94.4% complete. Women had a higher prevalence of preoperative angina and lesser relief after surgery (p < 0.01). Because of this difference, only men presenting with angina preoperatively were analyzed in detail. In this subgroup, the cumulative percentage of patients with total relief of angina was 87% after the first year; thereafter, the percentage decreased 6%/year. The cumulative percentage of patients improved (those with no angina plus those with less angina than before surgery) was 97% after the first year; thereafter the percentage decreased 0.9%/year. Duration of angina preoperatively had no effect on recurrence unless preoperative duration was less than 6 months. Preoperative left ventricular function had little effect on relief of angina postoperatively. In a short follow-up, 1.5 to 2 years after the original study, we found that patients with postoperative angina had twice the mortality rate of those totally free of angina (p = 0.000004). Furthermore, those with angina at rest had twice the mortality rate of those who had angina but never at rest (p = 0.009).     

Left atrial myxoma: false negative echocardiographic findings in a tumor demonstrated by coronary arteriography.

A report of left atrial myxoma discovered at coronary arteriography by virtue of unusual tumor "vascularity" is presented in which establishing the diagnosis by means of echocardiography proved difficult. The difficulty may have been due to the highly vascular nature of the tumor with resultant loss of the acoustic reflectivity required for echocardiographic demonstration. Previous cases in which left atrial myxomas have shown arteriographically demonstrable "tumor vascularity" are reviewed.     

LDH isoenzymes and myocardial infarction in patients undergoing coronary bypass surgery: an excellent correlation.

To evaluate the efficacy of LDH isoenzymes in the detection of myocardial infarction in patients undergoing coronary bypass surgery, 73 patients were studied pre- and postoperatively by ECG, CPK, SGOT, total serum LDH, and LDH isoenzyme measurements. A reversal of the LDH1:LDH2 ratio was considered indicative of myocardial necrosis. Accordingly, the patients were separated into two groups: Group A (23 patients) who demonstrated an LDH1:LDH2 ratio exceeding 1.0 and Group B (50 patients) who failed to reveal an LDH1;LDH2 reversal. The two groups were similar in regard to preoperative evaluation and operative procedure performed. The postoperative ECG findings were significantly different. In Group A 18 of 23 patients (78 per cent) developed significant new Q waves. This occurred in only one patient in Group B. Significant arrhythmias occurred in 70 per cent of the patients in Group A as compared to 14 per cent of those patients in Group B. Severe congestive heart failure and/or clinical evidence of shock occurred in 39 per cent of Group A patients and in none in Group B. The results of our study indicate that the reversal of the LDH1:LDH2 ratio is a valuable tool for the evaluation of postoperative myocardial infarction.     

The influence of early repolarization variant on the exercise electrocardiogram: a correlation with coronary arteriograms

Sixteen adult patients with S-T segment elevation in their resting electrocardiograms characteristic of early repolarization variant (ERV) and chest pain syndromes of possible myocardial ischemia were evaluated with both treadmill exercise electrocardiography and coronary arteriography. Of 14 patients with normal coronary arteriograms, 13 had their resting S-T elevation return (“normalize”) to the isoelectric baseline with physical exercise, while one patient with normal arteriograms and normal left ventricular contractility but moderately elevated left ventricular end-diastolic pressure of unknown etiology developed significant S-T depression with exercise. Two patients with significant coronary atherosclerotic occlusive lesions developed “ischemic” S-T depression during treadmill testing. Symptoms developed during treadmill exercise did not distinguish patients with coronary artery disease from those without. Thus, while ERV at rest may be “normalized” by graded physical exercise in the absence of significant coronary atherosclerosis, the presence of ERV does not prevent the usual electrocardiographic manifestations of exercise-induced myocardial ischemia.     

Unusual complications of coronary bypass surgery.

Five patients after coronary bypass surgery developed unusual complications. Three developed new apical thrombi which are thought to be due to the trauma of the left ventricular vent or deterioration of the left ventricular contraction. Significant new mitral regurgitation in one patient probably is secondary to papillary muscle dysfunction as the result of stenosis distal to anastomoses. The leakage of angoigraphic material around distal anastomatic site is due to technical error. Although these unusual complications are very rare, however, they should be considered as potential source of morbidity in asymptomatic patients who leave the hospital after bypass surgery.     

Left ventricular performance and graft patency after coronary artery-saphenous vein bypass surgery: early and late follow-up.

Left ventircular performance and graft patency were studied postoperatively at 2 weeks in 19 patients, and at 9 months in 15 patients. At early follow-up, left ventricular ejection fraction and mean rate of circumferential shortening were unchanged for the group as a whole, but were slightly improved in patients who had had a moderately abnormal preoperative ejection fraction of 0.30 to 0.60. At late follow-up, 10 of 14 patients had occluded at least one graft or the proximal segment of the grafted coronary artery and had an associated decrease in ventricular function. The risk of graft occlusion was greater if the preoperative ejection fraction was decreased; seven of 10 patients with a preoperative EF of less than 0.60 suffered one or more graft occlusions, but only three of 16 patients with a preoperative EF greater than 0.60 had a postoperative graft occlusion (p is less than 0.05). The results suggest that bypass graft surgery is not generally indicated as a measure to improve ventricular function in patients with ischemic heart disease.     

M-mode and two-dimensional echocardiographic correlation with findings at catheterization and surgery in patients with mitral stenosis

Thirty-two consecutive patients referred to our institution for evaluation of rheumatic mitral stenosis were studied with M-mode echocardiography (M-mode E), two dimensional echocardiography (2DE), and cardiac catheterization. Twenty-three of these patients underwent mitral valve surgery, 11 requiring mitral valve replacement, and 12 requiring open mitral commissurotomy. Clinical and noninvasive parameters were assessed in order to predict catheterization-determined mitral valve areas as calculated by the Gorlin formula, and to predict the choice of operation in patients selected for surgery. For the prediction of valvular area, 2DE planimetry correlated highly (r = 0.89, p less than 0.01) with Gorlin formula results. The presence or absence of pericardial effusion, the anterior-posterior valve leaflet separation (M-mode E), and the left atrium-aortic index (2DE) correlated poorly with the degree of mitral stenosis as determined by the Gorlin formula. The most useful predictors of type of mitral surgery were age over 50 years, 2DE valve classification, the presence or absence of calcium at fluoroscopy, and degree of anterior leaflet-septal separation (M-mode E).     

Electrocardiographic changes simulating acute myocardial infarction caused by hyperkalemia: report of a patient with normal coronary arteriograms.

A patient is described with severe diabetic ketoacidosis and hyperkalemia who presented with an ECG resembling an acute anterior wall myocardial infarction. Treatment of hyperkalemia resulted in prompt return of the ECG towards normal. Subsequent work-up including exercise testing and selective coronary arteriography ruled out any significant coronary artery disease suggesting that the ECG changes were probably caused by hyperkalemia. While similar changes have rarely been described in the past, this would appear to be the first such case in whom coronary artery disease was ruled out by a negative exercise testing and coronary arteriography.     

Comparison of coronary artery bypass surgery and percutaneous transluminal coronary angioplasty including surgery for failed angioplasty

Selection and treatment of patients with ischemic heart disease is presently undergoing an evolutionary trend. Percutaneous transluminal coronary angioplasty (PTCA) has been recommended as the initial procedure for many patients with coronary artery disease and has thus redefined candidates for coronary artery bypass surgery. During our first years of experience with percutaneous angioplasty, 339 patients underwent the procedure and were compared with 338 patients who underwent isolated coronary artery bypass surgery. Patients who underwent PTCA had a shorter duration of angina and a lower number of prior myocardial infarctions and were found to have better left ventricular function (p less than 0.01). PTCA was considered initially successful in 87% (295 of 339) of patients. The most common finding at operation in those with failed angioplasty who underwent urgent or emergency revascularization was dissection of atheromatous plaque. Although the cumulative frequency of new Q waves in the entire 18-month angioplasty series was low (2.7%), the incidence was high (18%) in those with angioplasty failure and subsequent operation (N = 20) and significantly greater than in patients who had elective coronary artery bypass surgery (3.6%). Use of inotropic agents and lidocaine for ventricular arrhythmias was significantly higher in patients with unsuccessful PTCA who required operation than in those who underwent elective bypass surgery (10% vs 3% and 10% vs 1.5%, respectively; p less than 0.01). In an analysis of our entire experience between October 1980 and June 1982, 777 patients who had PTCA and 2068 patients who underwent coronary artery bypass surgery were analyzed for differences in clinical complications and early outcome.(ABSTRACT TRUNCATED AT 250 WORDS)