The increased need for a permanent pacemaker after reoperative cardiac surgery.

OBJECTIVE: The requirement for permanent pacemaker implantation after most initial cardiac surgical procedures generally is less than 3%. To identify the incidence and factors related to permanent pacemaker need after repeat cardiac surgery, we retrospectively studied 558 consecutive patients undergoing at least one repeat cardiac operation. METHOD: Univariable and multivariable analyses of comorbidity, preoperative catheterization values, and operative data were performed to identify factors related to pacemaker implantation. RESULTS: In this group, 54 patients (9.7%) required a permanent pacemaker. A multivariable model showed a relationship between a permanent pacemaker and tricuspid valve replacement/annuloplasty associated with aortic/mitral valve replacement, preoperative endocarditis, increasing number of reoperations, the degree of hypothermia during cardiopulmonary bypass, and advanced age. Additional univariable predictors of pacemaker need included multiple valve replacement, increased cardiopulmonary bypass and aortic crossclamp times, and aortic valve replacement. Over 90% of patients who have or have not received permanent pacemaker implantation were in New York Heart Association class I to II, with a mean follow-up time of 6 years. Kaplan-Meier survival curves were statistically similar for both groups at 5 and 10 years after the operation. CONCLUSION: Permanent pacemaker implantation was required in 9.7% of patients undergoing repeat cardiac surgery. This represented approximately a fourfold increase compared with similar primary operations reported in other series. Factors strongly related to this need included valve replacement, preoperative endocarditis, number of reoperations, advanced age, and degree of hypothermia during cardiopulmonary bypass. The need for a permanent pacemaker after reoperations did not result in significant long-term impairment of functional status or longevity compared with those who did not require a permanent pacemaker.

Psychosocial factors related to noncardiac chest pain during treadmill exercise.

The authors examined historical, concurrent, and potentially secondary psychosocial problems related to noncardiac chest pain during exercise. The patients reporting chest pain during treadmill testing but who lacked cardiac ischemia (determined via nuclear scanning) were compared with the patients having both ischemia and chest pain, and with patients having neither ischemia nor chest pain. The noncardiac chest pain patients had the highest levels of 1) parental divorce and personal psychiatric treatment; 2) current depression, somatic awareness, and anger control; and 3) negative attitudes toward the health care system. The findings suggest that psychosocial problems predate, coexist with, and may result from noncardiac chest pain.

Correlates of unrecognized acute myocardial infarction detected via perfusion imaging.

Research using the electrocardiogram (ECG) indicates that about 1/3 of acute myocardial infarctions (AMIs) are unrecognized. To date, no studies of unrecognized AMIs have employed perfusion imaging, although it is more sensitive than the ECG and provides more information about infarct characteristics, such as size and location. In this study, 82 of 258 consecutive patients (31.8%) undergoing exercise testing with technetium-99m sestamibi perfusion imaging had fixed, nonartifactual perfusion defects, suggesting AMI. These patients were interviewed regarding their recognition of AMI; 27 patients (32.9%) had unrecognized AMI. Unrecognized AMI was significantly associated with (1) smaller infarcts, (2) infarcts not in the apical or septal regions, (3) diabetes mellitus, (4) lack of angina, (5) a negative family history for cardiac disease, and (6) being African-American. Many of these variables were significantly intercorrelated, and in multivariate analysis, unrecognized AMI remained significantly predicted by a smaller infarct and lack of angina. This study suggests that the incidence of unrecognized AMI detected via perfusion imaging on a clinic population is similar to that detected via electrocardiographic studies on community samples. This study also replicates prior findings of the medical history and demographic correlates of unrecognized AMI, and indicates that infarct size and location are also associated with unrecognized AMI.

Silent versus symptomatic myocardial ischemia: the role of psychological and medical factors.

This study examined the relationship of psychological, cardiac, and general medical history factors to asymptomatic (silent) versus symptomatic myocardial ischemia among 102 patients who underwent treadmill exercise testing and had perfusion imaging indicative of ischemia. During exercise, 68 patients exhibited silent ischemia, and 34 experienced chest pain. Patients with silent ischemia rated higher than symptomatic patients on anger control, externally oriented thinking, and somatosensory amplification, but did not differ on depression or global alexithymia. Anger control and externally oriented thinking remained independent correlates in multivariate analysis, controlling for demographic and cardiac factors. Groups did not differ on general medical or cardiac variables. Thus, this study suggests that affective and cognitive factors, but not biomedical factors, are associated with silent, as opposed to symptomatic, ischemia during exercise testing.

Echocardiographic evaluation of porcine bioprosthetic valves: experience with 309 normal and 59 dysfunctioning valves.

To determine the clinical value of echocardiographic evaluation of porcine bioprosthetic valves, the findings in all patients who had porcine bioprosthetic valve replacement and adequate quality echocardiographic studies from 1978 to 1982 were analyzed. The study includes 309 normal and 59 dysfunctioning valves. Valve dysfunction resulted from spontaneous cusp degeneration in 39 (34 valve regurgitations, 5 stenoses), infective endocarditis in 12, paravalvular regurgitation in 5, regurgitation of redundant cusps, mitral valve thrombi, and aortic stent stenosis in 3 others. Echocardiographic findings were correlated with gross surgical pathologic or autopsy findings in 45 of the 59 dysfunctioning valves. Echocardiographic abnormalities were demonstrated in 41 of 59 (69%) dysfunctioning valves. A systolic mitral or diastolic aortic valve flutter was diagnostic of a regurgitant valve caused by a torn or unsupported cusp margin and was observed in 28 of 34 (82%) regurgitant valves with no false-positive studies. Echocardiographic cusp thickness of greater than or equal to 3 mm correctly identified all regurgitant and stenotic valves with gross anatomic evidence of localized or generalized cusp thickening or calcific deposits. Echocardiographic valve abnormalities were observed in only 4 of 12 patients with infective endocarditis and in 1 of 5 with paravalvular regurgitation. Thus, echocardiography provides important information regarding the function of porcine bioprosthetic valves and is of value in the decision to replace these valves, especially when dysfunction is due to spontaneous cuspal degeneration. Echocardiography is neither sensitive nor specific in patients with infective endocarditis and paravalvular regurgitation.

Echocardiographic features of mitral obstruction due to bacterial endocarditis.

We describe a patient with mitral valvular obstruction due to vegetative endocarditis. The diagnosis was made before surgery by M-mode and two-dimensional echo-cardiograms, which revealed a mass of echoes obstructing the mitral orifice. This was confirmed subsequently at surgery. Both modes of echocardiography are of value in the noninvasive diagnosis of mitral valvular obstruction due to vegetative endocarditis, a condition which may be amenable to surgery for valvular replacement.

Echocardiographic diagnosis of left ventricular hypertrophy.

Echocardiograms were obtained on 27 adults with electrocardiographic criteria of left ventricular hypertrophy (LVH) to determine how echocardiograms might best identify LVH. Both the left ventricular (LV) posterior wall thickness and interventricular septal thickness were found by echocardiography to be increased (greater than or equal to 12 mm) in only 13 of 27 patients (48%) with LVH. The LV was dilated (greater than or equal to 58 mm) in the absence of posterior wall thickening in 9 of 27 patients (33%). The LV mass, estimated from standardly measured dimensions, was increased (greater than 200 g) in 21 of 27 patients (78%) and when measurements were made by the Penn method, mas was increased in all patients. These observations indicate that the echocardiographic estimation of LV mass is a more sensitive indicator of LVH than LV posterior wall and septal thickness. Since LVH is defined as an increased mass of LV muscle, these observations are consistent with this fundamental definition of left ventricular hypertrophy.

Correlation of exercise 201thallium myocardial scan with coronary arteriograms and the maximal exercise test.

Myocardial scans obtained by injecting radioactive 201thallium during exercise were correlated with electrocardiograms obtained at rest and during exercise, with coronary arteriographic abnormalities, and with left ventriculograms in 55 patients suspected of having coronary arterial disease. Thirty-nine patients had significant coronary arterial disease, 34 of whom had abnormal myocardial scans after exercise and 21 of whom had abnormal ECGs during exercise. The myocardial scan after exercise was most frequently abnormal in the presence of significant abnormalities in the Q wave or localized left ventricular asynergy and when ST-segment depression persisted for longer than ten minutes after exercise. All patients with single-vessel disease had abnormal myocardial scans after exercise, whereas five of 29 patients with two or more abnormal vessels had normal scans. Patients with coronary arterial disease were more likely to have a normal myocardial scan after exercise when the resting ECG and left ventriculogram were normal and when exercise-induced ST-segment depression persisted for less than ten minutes. The combination of the myocardial scan after exercise and the ECG during maximal exercise had a sensitivity of 98 percent. The myocardial scan after exercise alone had a specificity of 100 percent. These observations indicate that the myocardial scan obtained by injecting 201thallium during exercise is an important diagnostic adjunct in the identification of patients with coronary arterial disease.