Sudden death during empiric amiodarone therapy in symptomatic hypertrophic cardiomyopathy

Amiodarone is reported to improve symptoms and to prevent sudden death in patients with hypertrophic cardiomyopathy (HC). Amiodarone treatment (loading dose 30 g given over 6 weeks; maintenance dose 400 mg/day) was prospectively evaluated in 50 patients with HC in whom the drug was initiated because of symptoms refractory to conventional drug therapy (calcium antagonists and beta blockers). Twenty-one (42%) patients had ventricular tachycardia (VT) during Holter monitoring. Amiodarone significantly and often markedly improved the patients' New York Heart Association functional class status (from 3.3 to 2.7 at 2 months, p less than 0.001) and treadmill exercise duration (p less than 0.001). Eight patients, however, died (7 suddenly) during a mean follow-up period of 2.2 +/- 1.8 years. Of the 7 sudden deaths, 6 occurred within 5 months of initiation of treatment. The 6-month and 1- and 2-year survival rates were 87, 85 and 80%, respectively. The survival rate of patients with VT was significantly worse than that of patients without VT (61 vs 97% at 2 years; p less than 0.01). Sudden death occurred despite abolition of VT on Holter monitoring. Amiodarone increased left ventricular peak filling rate by radionuclide angiography in 20 of 33 patients (61%) (p less than 0.01). Decrease in peak left ventricular filling rate within 10 days of amiodarone therapy (8 of 33 patients) was associated with subsequent sudden death (p less than 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of viable myocardium in patients with chronic coronary artery disease and left ventricular dysfunction. Comparison of thallium scintigraphy with reinjection and PET imaging with 18F-fluorodeoxyglucose

In patients with chronic coronary artery disease and left ventricular dysfunction, the distinction between ventricular dysfunction arising from myocardial fibrosis and ischemic, but viable, myocardium has important clinical implications. By positron emission tomography (PET), enhanced fluorine-18-labeled fluorodeoxyglucose (FDG) uptake in myocardial segments with impaired function and reduced blood flow is evidence of myocardial viability. Reinjection of thallium-201 at rest immediately after stress-redistribution imaging may also provide evidence of myocardial viability by demonstrating thallium uptake in regions with apparently "irreversible" defects. To compare these two methods, we studied 16 patients with chronic coronary artery disease and left ventricular dysfunction (ejection fraction, 27 +/- 9%), all of whom had irreversible defects on standard exercise-redistribution thallium single-photon emission computed tomography (SPECT) imaging. Thallium was reinjected immediately after the redistribution study, and SPECT images were reacquired. The patients also underwent PET imaging with FDG and oxygen-15-labeled water. A total of 432 myocardial segments were analyzed from comparable transaxial tomograms, of which 166 (38%) had irreversible thallium defects on redistribution images before reinjection. FDG uptake was demonstrated in 121 (73%) of these irreversible defects. Irreversible defects were then subgrouped according to the degree of thallium activity, relative to peak activity in normal regions. Irreversible defects with only mild (60-85% of peak activity) or moderate (50-59% of peak) reduction in thallium activity were considered viable on the basis of FDG uptake in 91% and 84% of these segments, respectively. In contrast, in irreversible defects with severe reduction in thallium activity (less than 50% of peak), FDG uptake was present in 51% of segments. In such severe defects, an identical number of segments (51%) demonstrated enhanced uptake of thallium after reinjection. In these severe "irreversible" defects, data on myocardial viability were concordant by the two techniques in 88% of segments, with 45% identified as viable and 43% identified as scar on both PET and thallium reinjection studies. These observations suggest that thallium imaging can be used to identify viable myocardium in patients with chronic coronary artery disease and left ventricular dysfunction. Most irreversible defects with only mild or moderate reduction in thallium activity represent viable myocardium as confirmed by FDG uptake.(ABSTRACT TRUNCATED AT 400 WORDS)

Minimum left ventricular pressure during beta-adrenergic stimulation in human subjects. Evidence for elastic recoil and diastolic "suction" in the normal heart

The influence of elastic recoil and restoring forces on diastolic left ventricular pressure decay and minimum left ventricular pressures has been demonstrated in animal models but has not been studied in the human heart. To investigate this issue in the normal human left ventricle, we studied eight patients with chest pain and normal coronary arteries with simultaneous measurement of left ventricular volume (by radionuclide angiography) and pressure (by micromanometer catheter) and coronary sinus blood flow. Electrocardiographic-gated data were obtained in the basal state, during rapid atrial pacing, and during isoproterenol infusion to a similar heart rate. Compared with pacing, isoproterenol increased ejection fraction and reduced end-systolic volume (p less than 0.005), end-systolic pressure (p less than 0.005), and the half-time of pressure decline after peak negative dP/dt (T1/2) (p less than 0.001). Negative diastolic pressure developed in seven of eight patients during isoproterenol (range, -0.5 to -2.4 mm Hg) but in only one of eight during pacing (-0.2 mm Hg). These reduced diastolic pressures during isoproterenol were accompanied by increased stroke volume (reflecting increased transmitral flow) and diminished pulmonary wedge pressure (reflecting left atrial pressure). The magnitude of reduction in minimum diastolic pressure during pacing and isoproterenol was related to the change in end-systolic volume (r = 0.79, p less than 0.001), ejection fraction (r = -0.74, p less than 0.001), T1/2 (r = -0.57, p less than 0.02), and coronary sinus flow (r = 0.73, p less than 0.005). Stronger correlations were observed in analyzing changes during isoproterenol alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced detection of ischemic but viable myocardium by the reinjection of thallium after stress-redistribution imaging

BACKGROUND

The identification of ischemic but viable myocardium by thallium exercise scintigraphy is often imprecise, since many of the perfusion defects that develop in ischemic myocardium during exercise do not "fill in" on subsequent redistribution images. We hypothesized that a second injection of thallium given after the redistribution images were taken might improve the detection of ischemic but viable myocardium.

METHODS

We studied 100 patients with coronary artery disease, using thallium exercise tomographic imaging and radionuclide angiography. Patients received 2 mCi of thallium intravenously during exercise, redistribution imaging was performed three to four hours later, and a second dose of 1 mCi of thallium was injected at rest immediately thereafter. The three sets of images (stress, redistribution, and reinjection) were then analyzed.

RESULTS

Ninety-two of the 100 patients had exercise-induced perfusion defects. Of the 260 abnormal myocardial regions identified by stress imaging, 85 (33 percent) appeared to be irreversible on redistribution imaging three to four hours later. However, 42 of these apparently irreversible defects (49 percent) demonstrated improved or normal thallium uptake after the second injection of thallium, with an increase in mean regional uptake from 56 +/- 12 percent on redistribution studies to 64 +/- 10 percent on reinjection imaging (P less than 0.001). Twenty patients were restudied three to six months after coronary angioplasty. Of the 15 myocardial regions with defects on redistribution studies that were identified as viable by reinjection studies before angioplasty, 13 (87 percent) had normal thallium uptake and improved regional wall motion after angioplasty. In contrast, all eight regions with persistent defects on reinjection imaging before angioplasty had abnormal thallium uptake and abnormal regional wall motion after angioplasty.

CONCLUSIONS

These data indicate that the reinjection of thallium improves the detection of ischemic myocardium and that myocardial regions with improved thallium uptake on reinjection imaging represent viable but jeopardized myocardium.

Comparative assessment of chordal preservation versus chordal resection during mitral valve replacement

Left ventricular function often deteriorates after mitral valve replacement for mitral regurgitation. It has been postulated that disruption of the mitral valve apparatus at operation is a major mechanism of postoperative dysfunction. The hypothesis tested in this investigation was that chordal preservation results in more favorable left ventricular function. Sixty-nine patients with isolated mitral regurgitation who underwent mitral valve replacement were studied before and 6 months after operation by treadmill exercise testing, catheterization, echocardiography, and radionuclide angiography. Nine patients underwent mitral valve replacement with preservation of the entire mitral apparatus and five with preservation of the posterior leaflet and attached chordae. The remaining 55 had mitral valve replacement with complete excision of the native valve. Preoperatively, there were no differences among groups in age, gender, exercise capacity, cardiac index, rest or exercise ejection fraction, fractional shortening, or pulmonary artery pressures. There were four perioperative deaths (7%) and eight late deaths among the 55 patients with chordal resection but no early or late deaths of patients whose chordae were preserved (p = 0.05). In patients in whom the chordae were excised, exercise capacity, left ventricular systolic dimensions, and cardiac index did not improve after mitral valve replacement, and left ventricular function deteriorated, as evidenced by a reduction of both the resting and exercise ejection fractions (from 46% +/- 13% to 31% +/- 13%, p = 0.0001, and from 49% +/- 12% to 37% +/- 14%, p = 0.0007, respectively) and fractional shortening (from 34% +/- 10% to 26% +/- 14%, p = 0.0001). In contrast, exercise capacity improved after mitral valve replacement in patients in whom the entire apparatus was spared (by 4 +/- 3 minutes, p = 0.05), left ventricular systolic dimensions decreased (from 44 +/- 8 to 36 +/- 9 mm, p = 0.03), and left ventricular function was maintained or improved, as evidenced by preservation of the resting ejection fraction (preoperative, 50% +/- 14%; postoperative, 54% +/- 11%; p = no significant difference), exercise ejection fraction (46% +/- 16% versus 52% +/- 9%, p = no significant difference), fractional shortening (from 31% +/- 9% to 28% +/- 9%, p = no significant difference), and an increase in the cardiac index (from 2.0 +/- 0.3 to 2.7 +/- 0.5 L/min/m2, p = 0.05). No statistically significant differences between posterior chordal resection only and preservation of the entire apparatus were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular hypertrophy and impaired diastolic filling in essential hypertension. Diastolic mechanisms for systolic dysfunction during exercise

Left ventricular ejection fraction is normal at rest but may respond abnormally to exercise in many patients with essential hypertension. To assess the determinants of the abnormal ejection fraction response to exercise, we performed radionuclide angiography at rest and during exercise in 41 hypertensive patients without coronary artery disease. In 22 patients (group 1), the ejection fraction increased more than 5% during exercise; in the other 19 patients (group 2), the ejection fraction either increased by less than 5% or decreased with exercise. Left ventricular diastolic filling was impaired at rest in patients in group 2 compared with group 1, with reduced peak filling rate (2.5 +/- 0.4 vs. 3.1 +/- 0.7 end-diastolic volume/sec; p less than 0.01) and prolonged time to peak filling rate (175 +/- 28 vs. 153 +/- 22 msec; p less than 0.01). Impaired diastolic filling in group 2 was associated with less augmentation in end-diastolic volume during exercise compared with group 1 (p less than 0.01). These observations were not dependent on the threshold value that was arbitrarily chosen to define an abnormal ejection fraction response, as there were significant correlations for the entire group between the magnitude of change in ejection fraction with exercise and both the resting peak filling rate (r = 0.46) and the change in end-diastolic volume with exercise (r = 0.62).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of fixed and variable temporal resolution methods for creating gated cardiac blood-pool image sequences

In each of 50 resting subjects, two gated blood-pool image sequences were created from the same LIST mode data set. One sequence was created using a sorting method that spans each individual cardiac cycle with the same number of images (the "variable temporal" or VT method), while the other (the "fixed temporal" or FT method) spans the average cardiac cycle with images of fixed temporal duration. Left ventricular time-activity curves were extracted from each sequence using identical regions-of-interest and analyzed with identical methods to obtain estimates of ejection fraction, peak ejection rate, peak filling rate, and the times of occurrence of these peak rates. Differences among certain of these parameters in kind and amount support the hypothesis that estimates of resting cardiac function are more accurately portrayed by the FT method. The magnitudes of these differences are small for systolic parameters but large for early diastolic parameters. Thus, although both methods might be used for measuring systolic function, the FT method will yield a more accurate estimate of peak filling rate in resting subjects.

Cardiac blood-pool imaging. II: Applications in noncoronary heart disease

The role of radionuclide ventriculography in the initial evaluation, periodic assessment, and therapeutic follow-up of patients with valvular disease, hypertensive heart disease, lung disease, and cardiomyopathy is discussed.

Diagnosis of coronary artery disease by radionuclide angiography: effect of combining indices of left ventricular function

The aim of this study was to determine whether the diagnostic capability of radionuclide angiography (RNA) in detecting coronary artery disease (CAD) might be improved by using several indices of left ventricular (LV) function in concert. Three different models (rest data, exercise data, and rest plus exercise data) were derived by stepwise multivariate discriminant analysis of RNA data in 65 normal volunteers and 111 patients with CAD and normal ejection fraction (EF) at rest. The model with only resting indices yielded a diagnostic capability comparable to the simple measure of EF response to exercise (area under receiver operating characteristic curve = 89% and 91%, respectively). Both the exercise and rest plus exercise models gave better results (area = 94% and 97%, respectively), but only the rest plus the exercise model was better than the EF response alone (p less than 0.001). Thus (a) if resting studies alone are performed, the diagnostic potential of RNA may be improved by combining several indices of resting function; and (b) combined rest and exercise data may improve the sensitivity of RNA in detecting CAD over what could be obtained with the EF response to exercise alone.

Electrophysiologic abnormalities in patients with hypertrophic cardiomyopathy. A consecutive analysis in 155 patients

Electrophysiologic studies (EPS) were performed in 155 patients with hypertrophic cardiomyopathy (HCM). Indications for EPS were cardiac arrest in 22 patients, syncope in 55 patients, presyncope in 37 patients, asymptomatic ventricular tachycardia (VT) in 24 patients, palpitations in 10 patients, and a strong family history of sudden cardiac death in seven patients. Thirty-five (23%) patients had significant resting left ventricular outflow tract obstruction. Electrophysiologic abnormalities were present in 126 (81%) patients. A high prevalence of abnormal sinus-node function (66%) and His-Purkinje (HV) conduction (30%) was noted. The most commonly induced supraventricular arrhythmias were atrial reentrant tachycardia and atrial fibrillation (10% and 11% of patients, respectively). Accessory atrioventricular pathways were present in seven (5%) patients. Programmed ventricular stimulation (PVS) induced nonsustained ventricular tachycardia in 22 (14%) patients and sustained ventricular arrhythmia in 66 (43%) patients. Sustained ventricular arrhythmia was polymorphic VT in 48 (73%) patients, monomorphic VT in 16 (24%) patients, and ventricular fibrillation in two (3%) patients. Induction was with two premature stimuli in 19 (29%) patients and three premature stimuli in 47 (71%) patients. Of 17 cardiac arrest survivors with sustained ventricular arrhythmia, 16 (94%) patients required three premature stimuli for arrhythmia induction. Sustained ventricular arrhythmia was induced at a right ventricular site in 51 (77%) patients and at a left ventricular site in 15 (23%) patients. Univariate analysis showed a significant (p less than 0.05) association between inducibility of sustained ventricular arrhythmia and VT on Holter in patients with a history of cardiac arrest or syncope but not in patients with presyncope or asymptomatic patients. Multivariate logistic regression analysis revealed that the following were significantly associated with inducibility of sustained ventricular arrhythmia: clinical presentation (cardiac arrest more than syncope more than presyncope more than asymptomatic patients, p = 0.0002; chronic or inducible atrial fibrillation, p = 0.002; and male gender, p = 0.04). In contrast, there was no clinical correlate of induced nonsustained VT.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of temporal smoothing on quantitation of left ventricular function by gated blood pool scintigraphy

Frequently, indexes of systolic and diastolic left ventricular (LV) function obtained from radionuclide angiography are computed after the LV time-activity curve has been temporally smoothed. This smoothing process may introduce important systematic errors into the analysis. To assess this potential effect, high temporal resolution time-activity curves (20 ms/point) were obtained in 113 normal subjects, 175 patients with coronary artery disease and 171 patients with hypertrophic cardiomyopathy. The curves were then subjected to 0-, 3-, 5-, 7- and 9-point temporal smoothing. In each group, increased smoothing progressively and consistently underestimated ejection fraction by up to 5% (p less than 0.001) and peak ejection rate by up to 14% (p less than 0.001). A greater effect on peak filling rate was observed: 5-point and 9-point smoothing reduced peak filling rate by 10% and 23% in normal subjects, 3% and 10% in patients with coronary artery disease and 7% and 15%, respectively, in patients with hypertrophic cardiomyopathy (all p less than 0.001). These errors were compounded further when the same data obtained at lower temporal resolution (40 ms/point) were analyzed: 5-point and 9-point smoothing resulted in underestimation of peak filling rate by 20% and 46% in normal subjects, 13% and 43% in coronary artery disease and 16% and 34% in hypertrophic cardiomyopathy. The underestimation was not uniform, and its magnitude varied considerably among individuals in each of the 3 groups. Thus, smoothing of LV time-activity curves may result in significant systematic errors in computation of indexes of LV systolic and diastolic function, especially in data with poor temporal resolution. These concepts apply to other imaging methods, such as magnetic resonance imaging and cine-computed tomography, that assess LV function from the LV volume curve. Although ejection fraction is affected only mildly by these errors, both peak filling rate and peak ejection rate may be severely underestimated.

Enhanced regional left ventricular function after distant coronary bypass by means of improved collateral blood flow

To determine whether coronary artery bypass surgery can improve function in left ventricular regions not amenable to direct revascularization, 24 patients with multivessel coronary artery disease were studied by radionuclide angiography and coronary arteriography before and 6 months after coronary artery bypass surgery. All had proximal stenosis of the left circumflex artery or a major obtuse marginal branch. Left ventricular regional function was assessed by dividing the left ventricular region of interest into 20 sectors; the 8 sectors corresponding to the posterolateral free wall were used to assess function in the left circumflex artery distribution. Change in function in the left anterior descending territory was not analyzed because of the non-specific septal hypokinesia that develops postoperatively. For the total group, coronary artery bypass surgery significantly increased both global left ventricular ejection fraction during exercise (43 +/- 13% to 50 +/- 14%, p less than 0.001) and the change in ejection fraction from rest to exercise (-7 +/- 10% to 0 +/- 6%, p less than 0.001). Such improvement was observed in 9 of 10 patients with all stenoses bypassed, and to an equivalent degree in 9 of 10 patients in whom the left circumflex artery either could not be bypassed or the bypass graft was occluded (but bypass grafts to other coronary arteries were patent). Similarly, regional ejection fraction in posterolateral segments during exercise also increased comparably after operation in patients with a patent (from 57 +/- 18% to 70 +/- 19%, p less than 0.001) or nonpatent (from 51 +/- 14% to 68 +/- 14%, p less than 0.001) left circumflex graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative effects of verapamil and nitroprusside on left ventricular function in patients with hypertension

The effects of verapamil were compared with those of nitroprusside at matched mean arterial pressures and heart rates in 10 symptomatic hypertensive patients during cardiac catheterization. Simultaneous radionuclide angiography and micromanometer pressure measurements were obtained to assess left ventricular pressure-volume relations. Compared with control conditions, verapamil increased left ventricular end-diastolic volume index from 57 +/- 16 to 70 +/- 28 ml/m2 (p = 0.05) without a significant increase in left ventricular end-diastolic pressure (from 10 +/- 4 to 13 +/- 6 mm Hg). Despite a downward and rightward shift in the end-systolic pressure-volume relation indicating negative inotropic effects, ejection fraction did not decrease significantly (from 52 +/- 9% to 46 +/- 9%); cardiac index and stroke volume index remained unchanged. The change in stroke volume index with verapamil was directly related to the magnitude of change in end-diastolic volume index (r = 0.82, p less than 0.005), suggesting that the increase in end-diastolic volume did not arise purely from negative inotropic effects. Systemic vascular resistance index decreased from 42 +/- 8 to 34 +/- 7 mm Hg.min.m2/liter (p less than 0.05). In contrast, nitroprusside decreased left ventricular end-diastolic volume index from 57 +/- 16 to 41 +/- 10 ml/m2 (p less than 0.05), cardiac index from 3.2 +/- 0.7 to 2.8 +/- 0.6 liters/min per m2 (p less than 0.05) and stroke volume index from 28 +/- 6 to 24 +/- 5 ml/m2 (p less than 0.01), with no change in systemic vascular resistance index (40 +/- 10 mm Hg.min.m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Verapamil prevents silent myocardial perfusion abnormalities during exercise in asymptomatic patients with hypertrophic cardiomyopathy

Recent studies indicate that reversible 201Tl perfusion defects, compatible with silent myocardial ischemia, commonly develop during exercise in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy (HCM). To determine whether this represents a dynamic process that may be modified favorably by medical therapy, we studied 29 asymptomatic or minimally symptomatic patients with HCM, aged 12-55 years (mean, 28), with exercise 201Tl emission computed tomography under control conditions and again after 1 week of oral verapamil (mean dosage, 453 mg/day). Treadmill time increased slightly during verapamil (21.0 +/- 3.6 to 21.9 +/- 2.7 minutes, p less than 0.005), but peak heart rate-blood pressure product was unchanged (26.3 +/- 6.0 X 10(3) compared with 25.0 +/- 6.4 X 10(3). Two midventricular short-axis images per study were divided into five regions each, and each of these 10 regions was then analyzed on a 0-2 scale by three observers blinded with regard to the patients' therapy. Average regional scores of 1.5 or less were considered to represent perfusion defects, and a change in regional score of 0.5 or more was considered to constitute a significant change. During control studies, 15 patients (52%) developed perfusion defects with exercise (average, 3.7 regions per patient). In 14 of these patients, all perfusion defects completely reversed after 3 hours of rest; one patient had fixed defects. After administration of verapamil, exercise perfusion scores improved in 10 of the 14 patients (71%) with reversible defects; there was overall improvement in 34 of 50 (68%) regions with initially reversible perfusion defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of surgical reduction of left ventricular outflow obstruction on hemodynamics, coronary flow, and myocardial metabolism in hypertrophic cardiomyopathy

To assess the impact of operative reduction of left ventricular outflow obstruction in hypertrophic cardiomyopathy, measurements of great cardiac vein flow, oxygen and lactate content, left ventricular pressures, and cardiac index were measured at rest and during pacing stress in 20 consecutive patients (13, myotomy-myectomy; six, mitral valve replacement; one, both myotomy-myectomy and mitral valve replacement) who underwent both preoperative and postoperative studies. All had angiographically normal epicardial coronary arteries. Operation resulted in reduction in outflow gradient (64 +/- 38 to 4 +/- 7 mm Hg, p less than 0.001) and in left ventricular systolic pressure (186 +/- 32 to 128 +/- 22 mm Hg, p less than 0.001) and was associated with reduction in great cardiac vein flow (101 +/- 26 to 78 +/- 16 ml/min, p less than 0.001) and oxygen consumption in the anterior left ventricle and septum (11.9 +/- 4.1 to 8.4 +/- 1.9 ml O2/min, p less than 0.001) in the basal state. During rapid atrial pacing, 13 of 20 patients experienced chest pain postoperatively, whereas all 20 developed chest pain during preoperative pacing, with an improvement in pacing anginal threshold (or heart rate 150 if no chest pain was experienced) of 16 +/- 18 beats/min (p less than 0.001). The peak great cardiac vein flow (161 +/- 41 to 131 +/- 45 ml/min, p less than 0.025) and myocardial oxygen consumption (19.4 +/- 6.1 to 14.3 +/- 5.5 ml O2/min, p less than 0.005) during pacing, which correlated directly with the severity of the basal left ventricular gradient (p = 0.011 and p = 0.002, respectively), were also reduced by surgery. Lactate metabolism during pacing changed from net production before surgery to net consumption after operation (-17 +/- 47.6 to 4.4 +/- 29.8 mumol/min, p less than 0.01), with six of 20 patients producing lactate after surgery compared with 13 of 20 before surgery (p = 0.06). The six patients with the highest peak great cardiac vein flow (greater than 175 ml/min) during preoperative pacing had greater symptom and metabolic benefit during pacing after surgery compared with the 14 patients with lower peak coronary flow. Postpacing left ventricular end-diastolic pressure (30 +/- 7 to 23 +/- 7 mm Hg, p less than 0.001) and pulmonary artery wedge pressure (24 +/- 6 to 20 +/- 5, p less than 0.001) were reduced after surgery.(ABSTRACT TRUNCATED AT 400 WORDS)

Relation between exertional ischemia and prognosis in mildly symptomatic patients with single or double vessel coronary artery disease and left ventricular dysfunction at rest

The randomized multicenter trials indicate that survival in patients with coronary artery disease and left ventricular dysfunction is enhanced by surgical therapy compared with medical therapy. This beneficial effect of coronary bypass surgery was demonstrated in patients with either three vessel or left main coronary artery disease, but not in those with one or two vessel disease. To determine whether subgroups of mildly symptomatic patients with one or two vessel coronary artery disease and left ventricular dysfunction have an increased risk of death or cardiac events during medical therapy, 53 consecutive patients with angiographically defined one or two vessel disease and impaired left ventricular function (ejection fraction 20% to 40%) were studied by exercise electrocardiography (ECG) and rest and exercise radionuclide angiography. All but two patients had previous myocardial infarction, and all were asymptomatic or only mildly symptomatic during medical therapy. By univariate life table analysis, mortality during medical therapy was associated significantly with the ST segment response to exercise (p less than 0.05) and with both the exercise ejection fraction (p less than 0.05) and the magnitude of change in ejection fraction with exercise (p less than 0.005). In patients with an exercise ejection fraction greater than 30%, the probability of survival at 6 years was 97 +/- 3% (+/- SE) compared with a survival rate of 62 +/- 14% in the remaining subjects (p less than 0.005). Similarly, 6 year survival was 100% in patients whose ejection fraction increased from the value at rest but was only 74 +/- 10% in the remaining patients (p less than 0.005). Exercise capacity was not associated with survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-adrenergic stimulation with isoproterenol enhances left ventricular diastolic performance in hypertrophic cardiomyopathy despite potentiation of myocardial ischemia. Comparison to rapid atrial pacing

Impaired left ventricular relaxation and filling is an important pathophysiologic mechanism in hypertrophic cardiomyopathy. To determine whether isoproterenol, known to improve relaxation in isolated cardiac muscle, could favorably modify this effect, we assessed simultaneous left ventricular volume and regional systolic asynchrony (by radionuclide angiography), left ventricular pressure (by micromanometer catheters), and lactate metabolism in 12 patients with hypertrophic cardiomyopathy. Pressure-volume relations were studied during atrial pacing stress to induce myocardial ischemia and during isoproterenol infusion to similar heart rates. Angina occurred in 10 patients with pacing and in 11 patients during isoproterenol infusion; lactate consumption was reduced in nine patients during isoproterenol compared with pacing, including five patients who produced lactate with isoproterenol. During isoproterenol compared with pacing, peak left ventricular pressure was higher (205 +/- 33 vs. 142 +/- 21 mm Hg, p less than 0.001), ejection fraction was higher (77 +/- 10% vs. 71 +/- 12%, p less than 0.02), and regional systolic nonuniformity was diminished. Despite ischemia, these changes in load and nonuniformity during isoproterenol were associated with enhanced diastolic function compared with pacing tachycardia: isoproterenol reduced T 1/2, the half-time of pressure decline after peak negative dP/dt (from 46 +/- 10 to 33 +/- 6 msec, p less than 0.001), shifted the diastolic pressure-volume curve downward and rightward in 10 of 12 patients, and increased end-diastolic volume (from 77 +/- 18% to 100 +/- 11% of control values, p less than 0.001) with no change in end-diastolic pressure (19 +/- 7 to 19 +/- 5 mm Hg, p = NS). Thus, despite ischemia, isoproterenol improved left ventricular relaxation and filling compared with tachycardia in the absence of beta-adrenergic stimulation. Although isoproterenol is detrimental in hypertrophic cardiomyopathy by provoking ischemia, these data suggest that the adverse effects of ischemia on ventricular relaxation and distensibility may be alleviated by beta-adrenergic stimulation, possibly as a result of enhanced inactivation and restored load sensitivity.

Cardiorespiratory effects of immunotherapy with interleukin-2

The administration of interleukin 2 (IL-2) and lymphokine-activated killer (LAK) cells can mediate the regression of cancer. Treatment with IL-2 is associated with significant cardiorespiratory effects, as well as a leaky capillary syndrome requiring careful fluid management. A mild reversible depression of cardiac function is also associated with IL-2 treatment. All patients treated with recombinant IL-2 alone, with transfer of LAK cells, or with cyclophosphamide between December 1984 and September 1987 (total of 423 treatment courses in 317 total patients) were evaluated as to the development of significant cardiorespiratory toxicity. Of the 423 treatment courses, only 1.8% were associated with severe peripheral edema and only 2.8% and 3.1% respectively, were associated with significant ascites or pleural effusions. Thirty-nine of 423 patients (9.2%) had severe respiratory distress and 27 patients required intubation (6.4%). Cardiovascular effects included tachycardia and hypotension requiring vasopressor administration in 65% and intravenous (IV) fluid administration. Weight gain greater than or equal to 10% of body weight was noted in 32% of the 423 patients. Arrhythmias were primarily supraventricular (9.7%) and responded well to conventional medical treatments. Angina or ischemic changes were noted in 2.6% of patients and myocardial infarction in 1.2%. IL-2 caused peripheral vasodilation, with a significant decrease in peripheral vascular resistance (2,254 +/- 398 v 1,303 +/- 351 dyne.s.cm-5, P less than .0001), and an increase in heart rate (66.2 +/- 10 v 104.3 +/- 9.6 beats/min, P less than .0001). There was also evidence of mild cardiac dysfunction, with a significant decrease in the left ventricular stroke work (LVSW) index (P less than .0001) and ejection fraction (LVEF) (from 58% +/- 10% to 52% +/- 9%, P less than .03). A repeat LVEF performed after 1 to 3 months, had returned to baseline values (60% +/- 10%). A mean 64% increase in the rate of disappearance of radioactive iodine (125I) albumin (P less than .05) consistent with the development of a leaky capillary syndrome was noted. Patients with underlying cardiorespiratory diseases may be at greater risk during IL-2 administration and should not be selected to undergo this treatment.