Diagnostic accuracy of radionuclide techniques in patients with equivocal electrocardiographic exercise testing

[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries]

INTRODUCTION AND OBJECTIVES

Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block.

PATIENTS AND METHOD

9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed.

RESULTS

Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation.

CONCLUSIONS

In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.

[Role of noninvasive examinations in the management of ischemic heart disease.IV. Nuclear cardiology in chronic ischemic heart disease]

Nuclear cardiology has progressed in the past few years to the point of obtaining a consolidated position in the management of chronic ischemic heart disease. In the first part of our, methodology and interpretation criteria of the fundamental nuclear techniques (myocardial perfusion imaging and radionuclide angiography) are reviewed. In the second part, clinical indications in diagnostic and prognostic evaluations of patients with chronic ischemic heart disease are discussed, while remembering its usefulness in myocardial viability assessment.

Comprehensive noninvasive assessment of cardiac involvement in limited systemic sclerosis

OBJECTIVE

To assess cardiovascular abnormalities in patients with limited systemic sclerosis (SSc), using noninvasive cardiac techniques.

METHODS

Sixty-three patients with limited SSc were prospectively evaluated with Doppler echocardiography and thallium-201 perfusion scintigraphy after a cold-stress test and radionuclide ventriculography.

RESULTS

In the patients with limited SSc, there was a significantly high prevalence of abnormal left- and right-diastolic function parameters (P = 0.001 and P = 0.0002, respectively), thickening of papillary muscles (46%; P = 0.003), and mild mitral regurgitation (49%; P < 0.0001), compared with controls. Systolic pulmonary arterial hypertension was detected in 9 patients (14%), and pericardial effusion in 11 patients (18%). In 64% of patients with limited SSc, an ischemic response was detected on the thallium cold-stress scan; similarly, an ischemic response was detected in 57% of patients with primary Raynaud's phenomenon (P < 0.0001 versus controls).

CONCLUSION

Although the frequency of cardiovascular symptoms was low in patients with limited SSc, a significant rate of cardiovascular abnormalities was found by noninvasive cardiac techniques.

Evaluation of changes in myocardial perfusion and function on exercise in patients with coronary artery disease by gated MIBI scintigraphy

OBJECTIVE

To investigate the ability of gated methoxy-isobutylisonitrile (MIBI) scintigraphy to measure changes in myocardial function as well as perfusion with exercise.

SETTING

Regional cardiothoracic centre.

PATIENTS

43 presenting with chest pain, 28 with coronary artery disease on angiography, and 15 with normal coronary arteriograms.

RESULTS

Gated perfusion images showed an improvement in detecting regions with stenosed arteries compared with non-gated images (38/55 v 31/55, p < or = 0.01)). Functional analysis showed an increase in fractional shortening of 4.11% in subjects with normal coronary arteries, whereas in those with coronary disease a fall of 0.57% was found (p < or = 0.01). Both perfusion and function imaging showed an improved sensitivity compared with standard exercise testing (p < or = 0.01). When both function and perfusion imaging were analysed all patients with coronary disease were detected. There was agreement in abnormal regions in 33/55 territories supplied by a stenosed artery. Combined perfusion and function detected 49/55 (89%) of abnormal regions, thus improving the overall sensitivity from 38/55 (69%) by perfusion imaging alone (p < or = 0.01).

CONCLUSIONS

Gated methoxy-isobutylisonitrile scintigraphy can successfully evaluate perfusion and function on exercise, so improving the diagnostic usefulness of this agent.

Uncomplicated first myocardial infarction: strategy for comprehensive prognostic studies

To evaluate the prognostic role of combined cardiac studies (submaximal exercise test, thallium-201 scintigraphy, radionuclide exercise ventriculography, two-dimensional echocardiography, Holter monitoring and cardiac catheterization) in patients with a first acute myocardial infarction without complications during hospital admission, 115 consecutive patients aged less than 65 years were prospectively evaluated. The studies were carried out before hospital discharge and the patients were then clinically followed up for 12 months. During the follow-up period, 69 patients (60%) developed complications, which were severe in 23 (20%). Half of all complications and 70% of severe complications developed during the 1st follow-up month. Logistic regression analysis disclosed that the combination of studies with the highest predictive power for complications (probability of complications 99%) and severe complications (probability of severe complications 95%) was the association of exercise test + thallium-201 + echocardiogram. Four decision models (exercise test + echocardiography, exercise test + radionuclide ventriculography, thallium-201 scintigraphy + echocardiography, thallium-201 scintigraphy + radionuclide ventriculography) allowed the stratification of all patients in a particular risk category (high, intermediate or low). The best decision model was the association of thallium-201 scintigraphy + radionuclide ventriculography (probability of complications if both tests were positive 84%; probability of absence of severe complications if both tests were negative 88%), but there were no significant differences with the other models. Any association of a test detecting residual ischemia or functional capacity, or both (exercise test or thallium-201) and a test assessing ventricular function (echocardiography or radionuclide ventriculography) results in significant prognostic information in patients with an uncomplicated first acute myocardial infarction. Additional cardiac catheterization does not improve the predictive power of noninvasive studies, which should ideally be performed before hospital discharge because most complications develop during the 1st follow-up month.