[5-year results of arterial correction in transposition of great vessels]

A prospective study was performed on in-hospital patients between June 1985 and July 1992 to assess the 5 year results of surgical detransposition of the great arteries. Clinical examination, electrocardiography, echocardiography, right and left heart catheterisation with selective coronary angiography, isotopic right and left ventricular ejection fractions at rest and with infusion of dobutamine and SestaMibi myocardial perfusion scintigraphy at rest and with dipyridamole, were performed during the 5th year after surgery. Twenty-six children underwent this protocol: eight others did not come for examination because they had moved from the region, one of whom had suffered regressive postoperative myocardial infarction. All patients were asymptomatic and had only minor electrocardiographic changes. Stenosis of the pulmonary tract was observed in 38.5% but only one case of stenosis at the origin of the right pulmonary artery required percutaneous angioplasty, which was successful. Pulmonary regurgitation was a common echocardiographic finding (65.4% of cases) but rarely severe (1/26: 3.9%). Aortic regurgitation was also observed commonly (53.8%), nearly always mild, grade I (13/14 cases). No significant stenosis of the aortic anastomosis was observed. The right and left ventricular ejection fractions were normal at rest except in one case and all values improved with dobutamine. Myocardial scintigraphy did not show any perfusion defect and there was no stenosis or occlusion of the coronary arteries at coronary angiography. The authors conclude that the results of arterial detransposition at 5 years are satisfactory in this series, with no cases of major obstructive lesions, major ventriculo-arterial regurgitation, ventricular dysfunction or coronary lesions. However, longer term trials with larger numbers of patients are required to determine the real incidence of coronary lesions and the long-term outcome of the pulmonary valve in the systemic position.

Assessment of myocardial viability in patients with previous myocardial infarction by using single-photon emission computed tomography with a new metabolic tracer: [123I]-16-iodo-3-methylhexadecanoic acid (MIHA). Comparison with the rest-reinjection thallium-201 technique

OBJECTIVES

We compared the ability of rest single-photon emission computed tomography (SPECT) with [123I]-16-iodo-3-methylhexadecanoic acid (MIHA) and the thallium-201 (Tl-201) rest-reinjection technique to detect myocardial viability after infarction.

BACKGROUND

After myocardial infarction, MIHA frequently shows increased uptake in the areas with exercise Tl-201 defects (mismatch), even in patients with an irreversible Tl-201 reinjection defect. Whether such increased uptake is indicative of ischemic but viable myocardium is not known.

METHODS

We studied 38 patients who 1) underwent exercise SPECT Tl-201 with rest-reinjection and rest SPECT with MIHA before undergoing percutaneous transluminal coronary angioplasty (PTCA) of an infarct-related coronary artery, and 2) were found to have successful revascularization at follow-up angiography. The relation between SPECT results before PTCA and subsequent improvement in left ventricular wall motion was assessed.

RESULTS

A mismatch was evident before PTCA in 51 of 76 infarct-related segments and correlated with subsequent improvement in wall motion (overall accuracy 71%), even for the 27 segments whose exercise defects remained irreversible after Tl-201 reinjection (overall accuracy 81%). The finding of a mismatch clearly enhanced the results provided by the finding of > or = 50% Tl-201 uptake as determined at redistribution (p < 0.05), but not as determined at reinjection, although there was a trend toward a better specificity for the findings of a mismatch.

CONCLUSIONS

MIHA is an efficient marker of viability inside exercise-underperfused areas after infarction, even in patients with irreversible Tl-201 reinjection defects. Assessment by conventional SPECT of a mismatch between results obtained with a metabolic tracer (MIHA) and a flow tracer analyzed at exercise (Tl-201) as a marker of myocardial viability is a promising area of research.

[Effect of late revascularization of the responsible artery after infarction on left ventricular function and remodeling]

The effects of late angioplasty of the culprit artery after myocardial infarction on the decisive prognostic factors of left ventricular function and remodeling are not well known. When the culprit artery is narrowed but patent, angioplasty leads to improvement in segmental contractility and global left ventricular function: it does not seem to influence left ventricular end-diastolic volume. When the artery remains occluded, global and regional left ventricular function is also improved when the recanalised artery remains patent. Moreover, restoration of satisfactory artery patency prevents ventricular remodeling whereas in failed angioplasty or reocclusion, there is a progressive increase in left ventricular volume. However, these results observed in unselected patients could be improved: it would seem that the different beneficial effects only occur when there is residual myocardial viability; in the absence of signs of myocardial viability, the ventricular effects of limitations of angioplasty (incidence of restenosis or reocclusion in this specific context, lower primary success rate in complete arterial occlusion) explain the negativity of rare randomised studies comparing the outcome of left ventricular function depending on whether a conventional attitude or systematic revascularisation of the culprit artery is adopted.

[Anomalous origin of the left main coronary artery from the right coronary sinus and trajectory to the great vessels. Value of echocardiography in a child]

During a routine medical check-up, a pathological electrocardiogram was recorded in an asymptomatic 6 year old girl. The demonstration of coronary insufficiency by exercise stress testing and sestamib myocardio-scintigraphy led to the diagnosis of an anomalous origin of the left coronary artery. This vessel arose from the right coronary sinus and continued anteriorly to the main coronary artery. The data of the literature suggest that the risk of sudden death and of coronary insufficiency is associated with the passage of the left coronary artery between the aorta and pulmonary artery. The authors describe the anomalous origin of the left coronary artery and its trajectory with respect to the great vessels by echocardiography, using a high frequency transducer. The anterior direction of the left coronary artery in front of the main pulmonary artery may lead to ischaemia on effort even without stenosis at coronary angiography. Echocardiography may therefore be useful in children with positive exercise stress tests for diagnosing anomalous coronary vessels and their relationship with respect to the great vessels.

The usefulness of cardio-vascular visualization in the localization of mediastinal pheochromocytomas with I-131-MIBG

A case of malignant mediastinal paraganglioma showing moderate I-131-MetaIodoBenzylGuanidine (MIBG) uptake in the pericardiac region is presented. The patient had already undergone unilateral adrenalectomy with obvious clinical and biochemical findings of pheochromocytoma. The initial thoraco-abdominal CT and adrenal MRI were negative. The MIBG scan prior to the operation showed moderately increased uptake in the left adrenal region. No pheochromocytoma was found in the removed gland and the clinical signs persisted following the operation. The second MIBG scan after surgery showed a moderate left mediastinal uptake site by which it was difficult to rule out intracardiac localization. Without moving the patient, successive images of the tumor, myocardium and main mediastinal vessels were obtained by using the 24 hour activity of the initially injected 37 MBq Iodine-131-MIBG, 74 MBq Thallium-201 and 555 MBq Tc-99m-Human Serum Albumin (HSA), respectively. The superimposed bicolor images clearly showed the extracardiac localization of the tumor. The MRI scan confirmed this finding. Subsequent surgery found a malignant paraganglioma and metastatic mediastinal lymph nodes. We conclude that the visualization of the myocardium and the main mediastinal vessels with specific agents can be very useful in defining the exact location of I-131-MIBG detected mediastinal pheochromocytomas.

Long-term prediction of major ischemic events by exercise thallium-201 single-photon emission computed tomography. Incremental prognostic value compared with clinical, exercise testing, catheterization and radionuclide angiographic data

OBJECTIVES

This study sought to evaluate the prognostic role of exercise thallium-201 (Tl-201) single-photon emission computed tomography (SPECT) in patients with known or suspected coronary artery disease.

BACKGROUND

Compared with planar Tl-201 scintigraphy, Tl-201 SPECT allows enhanced assessment of myocardial perfusion abnormalities. However, the long-term prognostic value of exercise Tl-201 SPECT has not been ascertained and compared with that of other techniques of investigation.

METHODS

Predictors of ischemic events were sought in 217 patients with known or suspected coronary artery disease who underwent exercise Tl-201 SPECT, coronary angiography and rest radionuclide angiography and who initially received medical therapy. Predictive values were determined using Cox proportional hazards regression models.

RESULTS

During a mean (+/- SD) follow-up period of 70 +/- 19 months, 29 patients had a major ischemic event (cardiac death or myocardial infarction). Total extent of exercise defects was the best independent predictor by Tl-201 SPECT of major events (p < 0.001) and provided additional prognostic information compared with clinical, exercise testing and catheterization variables (p < 0.02). Extent of reversible Tl-201 SPECT perfusion defects provided additional prognostic information compared with extent of irreversible defects (p < 0.001) and was the sole Tl-201 SPECT variable providing additional prognostic information compared with radionuclide left ventricular ejection fraction (p < 0.02).

CONCLUSIONS

Total extent of exercise Tl-201 SPECT defects is a powerful long-term predictor of major ischemic events that enhances the prediction provided by clinical, exercise testing and coronary angiographic data. In view of its prognostic significance, extent of reversible Tl-201 SPECT defects might provide original information about improving prognosis by coronary revascularization.

Thallium-201 rest-reinjection and iodine-123-MIHA imaging of myocardial infarction: analysis of defect reversibility

Rest SPECT imaging with [123I]-16-iodo-3-methylhexadecanoic acid (MIHA) frequently shows an increased level of uptake in areas with irreversible defects on exercise 201TI SPECT. Such mismatch patterns between flow (201TI) and metabolic (MIHA) tracers might correspond to areas with ischemic but viable myocardium misidentified by 201TI imaging.

METHODS

Eighty-three patients with myocardial infarction underwent exercise SPECT 201TI with rest-reinjection and rest SPECT with MIHA. Defect areas on the exercise images were reversible on MIHA but not on 201TI reinjection images that were determined visually. The presence and extent of these areas were quantified from normalized uptake values for both tracers.

RESULTS

In areas with irreversible 201TI reinjection defects, MIHA detected exercise defect reversibility in 59% of patients. In areas with irreversible 201TI reinjection defects, the extent of visually determined defect reversibility on MIHA scans was related to the quantified extent of areas with 201TI uptake > or = 50% of normal; the correlation, however, was weak. In 86% of patients, areas with > or = 50% 201TI uptake were larger than those that were reversible on MIHA.

CONCLUSION

After myocardial infarction, rest SPECT with MIHA often enables visual detection of increased uptake in areas with irreversible 201TI reinjection defects.

Myocardial perfusion imaging with technetium-99m-Tc NOET: comparison with thallium-201 and coronary angiography

We compared TcN-NOET [bis(N-ethoxy, N-ethyl dithiocarbamato)nitrido 99mTc] and 201Tl images to estimate the utility of this compound in the detection of coronary artery disease (CAD).

METHODS

Twenty-five patients undergoing cardiac catheterization had stress-redistribution-reinjection 201Tl SPECT imaging, stress-delayed (2, 4 and 6 hr postinjection) and rest-delayed (4 hr postinjection) TcN-NOET SPECT imaging.

RESULTS

Nineteen patients had coronary stenosis > or = 50% and six were normal. Stress TcN-NOET and 201Tl imaging were concordant for the presence of CAD in 22/25 patients (88%, kappa = 0.76 +/- 0.20). The overall sensitivity of TcN-NOET SPECT imaging was 74% (14/19 patients) and 68% (13/19 patients) for 201Tl SPECT imaging. The specificity was 100% (6/6 patients) for both techniques. The overall agreement of TcN-NOET and 201Tl for the presence of disease in individual coronary arteries was 96% (72/75 arteries, kappa = 0.92 +/- 0.16). Segmental analysis of stress images showed a concordance in 211/225 segments (94%, kappa = 0.82 +/- 0.09). Comparison of the 4-hr images showed a concordance between 201Tl and TcN-NOET in 21/23 patients. Following TcN-NOET injection at rest, seven patients had a defect on the initial images, which had normalized 4 hr postinjection in four patients (57%).

CONCLUSION

Perfusion imaging with TcN-NOET and 201Tl gives comparable diagnostic information in patients undergoing exercise testing for assessment of CAD. Because of the normalization of myocardial activity 4 hr after injection in some patients, we conclude that TcN-NOET is a potential technetium compound equivalent to 201Tl.

Serial evaluation of dilated cardiomyopathy with exercise thallium-201 tomography: correlation with the evolution of left ventricular parameters

The purpose of this prospective study was to correlate (1) the initial findings of exercise thallium-201 tomography with the evolution of left ventricular parameters at long term follow-up in patients with dilated cardiomyopathy and (2) the changes of exercise thallium-201 tomography repeated 1 year later. We studied 19 men with dilated cardiomyopathy and normal coronary angiogram. Two patients died and three patients had heart transplantation during follow-up. The other 14 patients were assessed at baseline and 1-year follow-up. Thallium-201 tomograms were divided into 20 segments for each patient. Two groups were defined according to the evolution of left ventricular ejection fraction: group 1 (n = 7) had unchanged or decreased ejection fraction at follow-up (24 +/- 11% at baseline versus 22 +/- 11% at follow-up, ns) and group 2 (n = 7) had improved ejection fraction at follow-up (25 +/- 9% at baseline versus 49 +/- 8% at follow-up, P < 0.03). The number of total abnormal segments at stress were not statistically different at baseline between groups 1 and 2, and in group 1 between baseline and follow-up. Group 2 at follow-up had a reduced number of total abnormal segments (P < 0.03). The percentage of reversibility was similar in both groups at baseline and follow-up. On exercise thallium-201 tomography, neither the presence nor the reversibility of stress myocardial perfusion abnormalities can predict improvement of left ventricular ejection fraction in dilated cardiomyopathy. However, regression of dilated cardiomyopathy is accompanied by a reduction of stress myocardial perfusion abnormalities.

Comparison of right ventricular systolic function in idiopathic dilated cardiomyopathy and healed anterior wall myocardial infarction associated with atherosclerotic coronary artery disease

A case-controlled study assessed right ventricular (RV) systolic function in 10 patients with idiopathic dilated cardiomyopathy (IDC) and in 10 with healed anterior wall myocardial infarction associated with atherosclerotic coronary artery disease (CAD). Each patient was matched for sex, left ventricular ejection fraction +/- 5% and pulmonary artery mean pressure +/- 5 mm Hg. All patients had sinus rhythm and a left ventricular ejection fraction < 45%. A new, well-validated thermodilution technique was used to assess RV ejection fraction and volumes. RV ejection fraction was lower in the IDC than in the CAD group (25 +/- 14% vs 36 +/- 11%; p < 0.02). Linear correlations between RV parameters and pulmonary artery pressure were significantly present in both groups. However, the slopes of the equations were not statistically different. In comparison with healed anterior wall myocardial infarction with CAD and for similar levels of left ventricular dysfunction, RV systolic function appeared to be more altered in IDC.

Comparison of T1 estimation techniques in cardiac MRI

We have shown that the use of a simple combination of inversion recovery/spin-echo (IR/SE) sequences provides undeniably superior precision in quantitative in vivo myocardium T1 estimation than the standard multiple spin-echo approach. On a group of 25 healthy subjects, the T1 dispersion was, respectively, 3.8% for the IR/SE combination and 19.6% for the best SE pair combination. Moreover, repeated measurements were carried out on seven of the volunteers in order to assess T1 reproducibility. The mean intra-individual T1 precision was found to be 2.8% for the IR/SE pair and 20.0% for the best SE pair. The in vivo imaging work was supported and corroborated by a thorough treatment of the theoretical T1 errors. We also highlight the importance of quality control in quantitative MRI; a correction being required in the SE sequences to bring measured signal intensities into line with those predicted from simple theory.

Radionuclide assessment of regional differences in left ventricular wall motion and myocardial perfusion in idiopathic dilated cardiomyopathy

Regional variations in left ventricular contractility and myocardial perfusion are frequent in idiopathic dilated cardiomyopathy and might result from an increase in left ventricular wall stress responsible for regional wall motion abnormalities. The aim of the study was to perform radionuclide studies in patients with idiopathic dilated cardiomyopathy to assess regional left ventricular wall motion and myocardial perfusion abnormalities in this myocardial disease. We studied 29 men referred with idiopathic dilated cardiomyopathy and normal coronary angiograms. Rest radionuclide left ventriculography and exercise thallium-201 tomography were performed in all patients. The thallium-201 tomograms were divided into 20 segments for each patient. Mean left ventricular ejection fraction was 27 +/- 11%; 17 patients had diffuse hypokinesia (mean left ventricular ejection fraction: 24 +/- 9%) and 12 patients had predominant regional hypokinesia (mean left ventricular ejection fraction: 32 +/- 12%). Of all 580 tomographic segments, 186 had a reduction of thallium-201 uptake at exercise. Among them, reversibility was found in 53%. On the whole, 68% (158/232) of anterior, inferior and apical segments had a perfusion abnormality, compared with 8% (28/348) of septal and lateral segments (P < 0.0001). Left ventricular wall motion and myocardial perfusion abnormalities are heterogeneous and not evenly distributed in dilated cardiomyopathy. The alterations are predominant on the myocardial regions delineating the antero-posterior axis of the left ventricle. These findings suggest the possible role of increased left ventricular wall stress on this axis.

Usefulness of exercise SPECT-thallium to detect asymptomatic restenosis in patients who had angina before coronary angioplasty

The usefulness of exercise single photon emission computed tomography (SPECT)-thallium for detecting asymptomatic restenosis was assessed prospectively in 62 patients with angina before angioplasty, who underwent < or = 6-month re-angiography and exercise SPECT-thallium imaging. Among patients with restenosis, nine had recurrence of angina but eight did not. These two subgroups had equivalent percentages of restenosis (71 +/- 16% vs 64 +/- 16%, NS) and extent of reversible thallium defects (2.8 +/- 1.7 vs 4.1 +/- 2.6, NS), and both subgroups had poorer hemodynamic responses to exercise compared with patients without restenosis (maximal) rate-pressure product [X 100], 258 +/- 54 and 239 +/- 33 vs 302 +/- 61; p < 0.05 and p < 0.01, respectively). Exercise testing detected fewer patients with restenosis compared to exercise SPECT-thallium imaging, especially among asymptomatic patients (25% vs 100%, p < 0.005). Asymptomatic restenosis occurs frequently, induces an amount of stress ischemia equivalent to that of symptomatic restenosis, and is efficiently detected by exercise SPECT-thallium with rest-reinjection but not by exercise testing.

[Cardiac arrest reversed: causes and treatments]

The aim of this study was to report the probable mechanism of resuscitated cardiac arrest without acute myocardial infarction. Fifty-seven cases were recensed but the arrest was only documented in 44 subjects. Systematic non-invasive investigations and programmed stimulation showed that the diagnosis of cardiac arrest was probably false in 5 patients and, in the others, that a ventricular arrhythmia was probably the cause (63%). The occurrence of cardiac arrest under antiarrhythmic therapy may reveal an underlying abnormality requiring specific therapy (3/8). The absence of cardiac disease did not exclude the risk of VF (3 cases). When reproducible, ventricular arrhythmias were present during programmed stimulation, the prognosis was good if the arrhythmia could not be induced under antiarrhythmic therapy. It was easier to find an effective treatment for inducible ventricular fibrillation-flutter (13/17) than for inducible ventricular tachycardia (7/17). The prognosis was poor if the arrhythmia was unchanged during programmed stimulation under antiarrhythmic therapy and non-pharmacological treatment was required.

Synchronized inversion recovery-spin echo sequences for precise in vivo T1 measurement of human myocardium: a pilot study on 22 healthy subjects

An ECG-triggered, two-sequence MRI technique is proposed for the precise measurement of proton T1 relaxation times of the human myocardium at a field strength of 0.5 T. The combination of an inversion recovery (IR) sequence and a spin echo (SE) sequence is not new. It is, however, rarely used in quantitative in vivo cardiac studies. Our approach employs a synchronization of the 90 degrees read pulse to the systolic period. In a study of 22 healthy volunteers, the globally measured T1 value was estimated to be 714 +/- 23 ms. Four of the volunteers also underwent additional imaging scans for the purposes of reproducibility assessment. The T1 precision was found to be 3.9 +/- 1.1% for the IR/SE combination and 16.9 +/- 5.3% for a combination of SE sequences. Total imaging time for the IR and SE sequences was 19.2 +/- 3.0 mins. The relative rapidity of this classic technique and the T1 precision obtained give this technique an obvious application in the discrimination of normal and diseased myocardium. In the same study, valuable supplementary tissue characterization is provided by T2, calculated from the SE sequence. T2 was evaluated to be 50 +/- 3 ms.

Results of percutaneous transluminal coronary angioplasty of either the left anterior descending or left circumflex coronary artery in patients with chronic total occlusion of the right coronary artery

The acute and long-term results of percutaneous transluminal coronary angioplasty (PTCA) of the left coronary artery in 106 patients (group 1) with chronic occlusion of the right coronary artery were compared with those of 106 patients matched for sex (92 male) and age (56 +/- 10 years) undergoing left PTCA with a normal right coronary artery (group 2). Before the procedure, group 1 had more unstable angina (42 vs 29%; p < 0.05), more frequent prior myocardial infarction (80 vs 25%; p < 0.001), and a lower left ventricular ejection fraction (56 +/- 10% vs 65 +/- 11%; p < 0.005). Acute results were not different in the 2 groups with respect to primary success (group 1: 93%; and group 2: 89%) and complications (group 1: 2 with emergency coronary surgery, and 4 with periprocedural myocardial infarction and no death; and group 2: 1 with emergency coronary surgery, 1 death, and 3 with periprocedural myocardial infarction). At 6 months, 79 patients in group 1 and 71 patients in group 2 had reangiography; the rate of restenosis was 35% in group 1 and 42% in group 2. In both groups, left ventricular ejection fraction increased significantly in patients without restenosis (58 +/- 12% vs 63 +/- 10%, p < 0.001 [n = 44] in group 1; and 66 +/- 9% vs 70 +/- 10%, p < 0.001 [n = 29] in group 2). In group 1, improvement was significant only for patients without collaterals to the occluded right coronary artery (59 +/- 10% vs 66 +/- 7%; p < 0.003 [n = 24]).(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous transluminal coronary angioplasty in patients more than 75 years old: early and long-term results

Over 4 yr, 102 consecutive patients more than 75 yr old (56 men, 46 women; mean age 78 +/- 3 years, range: 76-89 years) underwent 120 percutaneous transluminal coronary angioplasty procedures. At baseline, 86% had severe anginal symptoms (Canadian class III or IV), 43% had a history of prior myocardial infarction; 61% had multivessel coronary artery disease, and mean left ventricular ejection fraction was 60 +/- 11%. Calcifications were observed on 66% of the dilated arteries. A total of 158 vessels (1.3 vessel per procedure) were attempted: 1 vessel in 89 procedures (74%), 2 vessels in 24 (20%) and 3 vessels in 7 (6%). The primary success rate was 80% per lesion (126/158) and 77% per procedure (92/120). Complications included 3 deaths (3%), 9 Q-wave infarctions (7.5%) and there was no emergency coronary bypass surgery. The primary success rate was significantly related to the absence of coronary calcifications on the dilated segment (88% versus 75%, p < 0.05) and to the initial patency of the dilated artery (subtotal stenosis: 83% versus total occlusion: 53%, p < 0.05). Follow-up data were obtained in the 79 consecutive patients with a duration of follow-up exceeding 8 months. The mean duration of follow-up was 23 +/- 13 months (range 8 to 61 months). No patient was lost to follow-up; 11 patients died (cardiac causes: 7), 2 had a non-fatal infarction, 7 had aortocoronary bypass surgery and 18 had repeat percutaneous transluminal coronary angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular overload and induced sustained ventricular tachycardia in operatively "repaired" tetralogy of Fallot

The aim of the study was to evaluate the main predictors of the inducibility of sustained ventricular tachycardia (VT) in patients with repaired tetralogy of Fallot. Thirty-five patients (age 12 +/- 6 years) underwent right-sided cardiac catheterization, echocardiography, radionuclide angiography and ventricular stimulation; 10 had (group 1) and 25 had no (group 2) sustained VT. Group 1 patients were significantly older at the time of surgery and had longer follow-up periods (7 +/- 3 vs 4 +/- 4 years, p less than 0.02; and 12 +/- 4 vs 5 +/- 2 years, p less than 0.001, respectively). Right ventricular (RV) systolic pressure, end-systolic and end-diastolic normalized RV volumes were higher in group 1 (48 +/- 14 vs 38 +/- 11 mm Hg, p less than 0.05; 1.23 +/- 0.2 vs 0.86 +/- 0.17, p less than 0.001; and 2.35 +/- 0.37 vs 1.70 +/- 0.22, p less than 0.001, respectively). RV end-diastolic pressure, left ventricular and RV ejection fractions were similar in the 2 groups. A stepwise discriminant analysis was made to predict patients with inducible sustained VT (group 1): Time period from surgery to follow-up (p less than 0.001), normalized RV end-systolic volume (p less than 0.002) and RV systolic pressure (p = 0.01) were higher in group 1 and allowed classification of 90% of patients in group 1 and 96% in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Evolution of myocardial ischemia and left ventricular function in patients with angina pectoris without myocardial infarction and total occlusion of the left anterior descending coronary artery and collaterals from other coronary arteries

Repeated episodes of myocardial ischemia might lead to progressive impairment of left ventricular (LV) function. This radionuclide study assessed myocardial ischemia and LV function several years after documented coronary occlusion without myocardial infarction. Over 5 years, 24 consecutive patients, who underwent cardiac catheterization for angina pectoris without myocardial infarction, had isolated total occlusion of the left anterior descending coronary artery with well-developed collateral vessels. Five patients were successfully treated by coronary bypass grafting and 3 by coronary angioplasty. Among the 16 medically treated patients, 1 was lost to follow-up and 1 died (extracardiac death). The mean (+/- standard deviation) follow-up (14 patients) was 48 +/- 15 months. At follow-up, 8 patients still had clinical chest pain, 11 received antianginal therapy, 4 patients had no stress ischemia and the other 10 had greater than or equal to 1 sign of stress ischemia. All patients had a normal LV ejection fraction at rest (mean 60 +/- 3%; range 55 to 65%). Collateral circulation preserves LV function at the time of occlusion and, in some cases, prevents the development of myocardial ischemia; in patients with persisting myocardial ischemia after well-collateralized coronary occlusion, LV function is not impaired at long-term follow-up.

Skeletal muscle metabolism in the leg during exercise in patients with congestive heart failure

1. Using 31P nuclear magnetic resonance, it has previously been demonstrated that patients with congestive heart failure exhibit a greater than normal phosphocreatine (PCr) depletion in the working skeletal muscles of the arm. We have studied the importance of the work necessary to reach a similar PCr depletion ([PCr]/([PCr] + [Pi]) = 0.5) in calf muscle. Our results show significantly lower values for patients with congestive heart failure in both aerobic and ischaemic conditions (respectively: 0.009 +/- 0.007 vs 0.026 +/- 0.013 W/kg body weight, P less than 0.01; 0.29 +/- 0.16 vs 0.90 +/- 0.25 J/kg body weight, P less than 0.01). 2. This original model of skeletal muscle exercise facilitates a comparison of PCr recovery rate due to a similarity in the PCr depletion and intracellular pH in the two series at the start of recovery. However, the PCr recovery rate is similar after both normoxic and ischaemic exercise, i.e. respective percentages of PCr increase in the first 25 s recovery spectrum were: (a) aerobic exercise, congestive heart failure 133 +/- 18%, control series 138 +/- 18%; (b) ischaemic exercise, congestive heart failure 114 +/- 13%, control series 118 +/- 12%. The absence of a difference in PCr recovery rate and the greater PCr depletion by ischaemic work in patients with congestive heart failure suggest modifications that cannot be explained by a reduced blood flow to the muscle. 3. When comparing the two series, intracellular pH evolved similarly in normoxia and ischaemia during both work and recovery. Thus, no increase in anaerobic glycolytic activity appears when equivalent PCr depletion has occurred.

Role of ancillary properties of beta-adrenoceptor antagonists in protecting the heart from anoxia

The mechanism of the cardioprotective action of beta-blocking drugs against anoxia or ischemia is still not clear. We used beta-blockers (5 x 10(-7) M) of various pharmacodynamic profiles in a model of isolated, perfused working guinea pig heart subjected to 20 min of anoxia to study this. The cardioprotective effects were evaluated by measuring the recovery of the flow indices after 15 min of reoxygenation. There was a significant cardioprotective action (as measured by the effect on stroke volume recovery and on recovery of other flow and work indices) of the beta-blocking properties (nadolol, P less than 0.05), of the membrane-stabilizing property [+)-propranolol, P less than 0.05) and of a combination of these two properties with (+/-)-propranolol, which had a significantly greater effect than nadolol (P less than 0.05). The addition of weak (acebutolol) or strong (pindolol) intrinsic partial agonist activity had no clear unfavourable effect, as the degree of cardioprotection was comparable with that obtained with (+/-)-propranolol. The stroke volume recovery (percent recovery after anoxia) in the control hearts was 42.57 +/- 12.75 compared to 54.84 +/- 6.94 in hearts pretreated with nadolol, 62.99 +/- 11.41 with (+)-propranolol, 71.02 +/- 11.36 with (+/-)-propranolol, 72.63 +/- 13.08 with acebutolol and 68.01 +/- 15.42 with pindolol. In vitro heart protection from anoxia with beta-blockers would appear to be related to beta-blocking activity and/or membrane stabilizing property but not a function of partial agonist activity. These ancillary properties of beta-blockers should thus be taken into account in studies on cardioprotection.