Comparative study for the identification of myocardial ischemia by contrast ventriculography under the effect of isosorbide mononitrate and by perfusional myocardial scintigraphy in patients with ischemic heart disease

OBJECTIVE: To evaluate and compare the usefulness of cineventriculographies, before and after nitrate use, to technetium-99m sestamibi scintigraphy for the identification of myocardial ischemia. METHODS: Twenty-six patients were studied at basal conditions and 5 minutes after intravenous administration of isosorbide mononitrate (0.3mg/kg), to evaluate the performance and regional wall motion of the left ventricle (LV). The results were compared to those obtained with technetium-99m sestamibi scintigraphy. RESULTS: Before nitrate, contrast ventriculography identified 30 normal segments, 62 hypokinetic segments, 28 dyskinetic segments, and 14 akinetic segments. After drug administration, 99 segments were normal, 11 hypokinetic, 11 dyskinetic, and 13 akinetic. Myocardial scintigraphy revealed 110 ischemic segments and 18 fibrotic segments (p<0.005). After drug administration, the ventriculography showed increase in the velocity of circumferential fiber shortening (p=0.0142), the ejection fraction (p=0.0462), decrease in the end-systolic volume (p=0.0031) and no change in end-diastolic volume. CONCLUSION: Contrast ventriculography using nitrate proved to be similar to perfusional myocardial scintigraphy in the identification of myocardial ischemia.

Dynamic three-dimensional reconstruction of the heart by transesophageal echocardiography

OBJECTIVE: To evaluate echocardiography accuracy in performing and obtaining images for dynamical three-dimensional (3D) reconstruction. METHODS: Three-dimensional (3D) image reconstruction was obtained in 20 consecutive patients who underwent transesophageal echocardiography. A multiplanar 5 MHz transducer was used for 3D reconstruction. RESULTS: Twenty patients were studied consecutively. The following cardiac diseases were present: valvar prostheses-6 (2 mitral, 2 aortic and 2 mitral and aortic); mitral valve prolapse- 3; mitral and aortic disease - 2; aortic valve disease- 5; congenital heart disease- 3 (2 atrial septal defect- ASD - and 1 transposition of the great arteries -TGA); arteriovenous fistula- 1. In 7 patients, color Doppler was also obtained and used for 3D flow reconstruction. Twenty five cardiac structures were acquired and 60 reconstructions generated (28 of mitral valves, 14 of aortic valves, 4 of mitral prostheses, 7 of aortic prostheses and 7 of the ASD). Fifty five of 60 (91.6%) reconstructions were considered of good quality by 2 independent observers. The 11 reconstructed mitral valves/prostheses and the 2 reconstructed ASDs provided more anatomical information than two dimensional echocardiography (2DE) alone. CONCLUSION: 3D echocardiography using a transesophageal transducer is a feasible technique, which improves detection of anatomical details of cardiac structures, particularly of the mitral valve and atrial septum.

Comparison between right and left ventricular myocardia during the human fetal period. Stereological evaluation

PURPOSE: To develop a stereological comparison between right (RV) and left ventricle (LV) myocardium during the third human gestational trimester. METHODS: Five human fetal hearts of the third trimester provided representative samples of 5 RV myocardium and 4 LV myocardium. The material was fixed in 10% buffered formaldehyde, and processed through routine methods. Fifteen microscopic fields were randomly chosen and counted in each ventricular myocardium using an "M-42" test system. The following stereological parameters were assessed: Vv (%), Lv (µm²), Sv (µm²/µm³), Vp (µm³), Nv (1/mm³) and total N. RESULTS: No significant difference between the stereological parameters of the myocardial structures assessed was evidenced, when comparing RV and LV. CONCLUSION: Right and left human ventricular myocardium are very similar during the fetal period at least in regard to their structural aspects.

Evaluation of the heart rate and arrhythmias following the Maze procedure for chronic atrial fibrillation

PURPOSE: To assess the presence and the prevalence of arrhythmias and the variability of the heart rate in the medium-term postoperative period following the maze procedure for chronic atrial fibrillation (AF). METHODS: Seventeen patients with a mean age of 51.7±12.9 years, who previously underwent the maze procedure without cryoablation for chronic atrial fibrillation, were evaluated with the 24 hour electrocardiogram (ECG) - Holter monitoring from the 6th month after the operation. Valvular and coronary procedures were concomitantly performed. RESULTS: The mean heart rate during Holter monitoring was 82±8bpm; the maximal heart rate was 126 ± 23bpm and the minimal heart rate 57±7bpm. Sinus rhythm was found in 10 (59%) patients and atrial rhythm was found in 7 (41%). Supraventricular extrasystoles had a rate of 2.3±5.5% of the total number of heartbeats and occurred in 16 (94%) patients. Six (35%) patients showed nonsustained atrial tachycardia. Ventricular extrasystoles, with a rate of 0.8±0.5% of the total heartbeats, occurred in 14 (82%) patients. The chronotropic competence was normal in 9 (53%) patients and attenuated in 8 (47%). The atrioventricular conduction (AV) was unchanged in 13 (76%) patients and there were 4 (24%) cases of first degree atrioventricular block (AVB). CONCLUSION: After the maze procedure, the values for the mean heart rate, AV conduction and chronotropic competence approach the normal range, although some cases show attenuation of the chronotropic response, first degree AV block or benign arrhythmias.

Are apolipoproteins A and B better than lipoproteins for assessing risk of obstructive coronary heart disease?

OBJECTIVE: To evaluate whether apolipoproteins A-I (Apo A-I) and B (Apo B) have, higher ensitivity (SN), specificity (SP) and positive predictive value (PPV) than lipoproteins (LP), total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), and triglycerides (TGL) in assessing the risk of coronary heart disease (CHD). METHODS: This is a transversal case-control study of 241 patients, who were divided into two groups: 1) 145 patients with CHD, and 2) 96 patients without coronary disease. A model of logistic regression to evaluate the relation between the LPs and CHD was developed in which variables with a p-alpha <0.1 were included. RESULTS: Apo A-I levels were higher in the patients without CHD, (OR 2.08, CI 1.20-3.57). There were no statistical differences between the values of Apo A-I and the remaining lipid fractions (Apo A-I: 67%; Apo B: 100%; PPV: TC= 71%; TGC=71%; HDL=71%; LDL=71%). The costs of the tests in Reais were as follows: Apo A-I: R$ 56.60; Apo B-100: R$ 56.60; TC: R$ 9.94; HDL: R$ 21.30; LDL: R$ 28.40; TGL: R$ 14.20. CONCLUSION: Levels of Apo A-I and Apo B have no advantage over conventional lipoproteins in predicting the risk of CHD, despite the statistical association between Apo A-I and CHD; in addition, their costs are higher than those of the conventional lipoproteins.

Detection of functional changes of the fetal heart in the first trimester of gestation

The authors consider the possibility of using color Doppler of the ductus venosus and the measurement of nuchal translucency as a screening test for alterations in fetal cardiac functions in the first trimester of gestation. Review of the literature suggests that the combination of the ultrasonographic measurement of nuchal translucency and Doppler at 10 and 14 weeks of gestation can be effective in detecting certain cardiac abnormalities. This conclusion, however, is preliminary and needs to be further investigated.

Assessment of functional capacity through oxygen consumption in patients with asymptomatic probable heart disease

PURPOSE: To compare peak exercise oxygen consumption (VO2peak) of healthy individuals with asymptomatic individuals with probable heart disease. METHODS: Ninety-eight men were evaluated. They were divided into two groups: 1) 39 healthy individuals (group N) with an age range of 50±4.6 years; and 2) 59 asymptomatic individuals with signs of atherosclerotic and/or hypertensive heart disease (group C) with an age range of 51.9±10.4 years. In regard to age, height, body surface area, percentage of fat, lean body mass, and daily physical activity, both groups were statistically similar. Environmental conditions during the ergometric test were also controlled. RESULTS: Maximal aerobic power (watts), VO2peak, maximal heart rate, and maximal pulmonary ventilation were lower in group C (p<0.01) than in group N; weight, however, was lower in group N (p=0.031) than in group C. Differences in the respiratory gas exchange index, heart rate at rest, and the maximal double product of the two groups were not statistically significant. CONCLUSION: Signs of probable heart disease, even though asymptomatic, may reduce the functional capacity, perhaps due to the lower maximal cardiac output and/or muscle metabolic changes.

Aortopulmonary window. Clinical and surgical assessment of 18 cases

OBJECTIVE: Aortopulmonary window (APW) is an uncommon congenital malformation. Its clinical presentation is dependent on the size of the defect and on the associated lesions. We evaluated our experience with this anomaly and compared it with 296 cases reported in the literature. METHODS: Retrospective study of 18 patients diagnosed as having APW (age range from 13 days to 31 years, 13 (72.2%) females), divided into two groups: Group A (GA): 10 patients with isolated APW, and Group B (GB): 8 patients with associated lesions. RESULTS: Heart failure occurred in 14 patients, and cyanosis in 3: 2 from GB (tetralogy of Fallot - TF, and double outlet right ventricle - DORV), and one from GA with pulmonary hypertension. In 5 patients from GA the diagnosis of mitral regurgitation was made based on a systolic murmur and LV hypertrophy on the EKG. In GB, clinical findings were determined by the associated defect. Diagnosis was established by echocardiography in 11 (61.2%) of the patients. In 3 patients, a wrong diagnosis of mitral regurgitation was made, in 1 a patent ductus arteriosus was diagnosed and in 3 others, the diagnosis of APW was masked by other important associated defects (2 cases of DORV and 1 case of TF). The diagnosis was made by catheterization in 3 (16.6%) patients, by surgery in 3 (16.6%) and by necropsy in 1 (5.5%). Corrective surgery was performed in 14 (77.7%) patients, with one immediate death and good long-term follow-up in the remaining patients. CONCLUSION: APW can be confused with other defects. Clinical findings, associated with an adequate echocardiogram can provide the information for the correct diagnosis.

Aortic valve assessment. Anatomical study of 100 healthy human hearts

PURPOSE: To assess anatomical characteristics of the aortic valve, so that they may be useful in diagnostic situations and surgical treatment. METHODS: The study analyzed 100 healthy fixed human hearts; 84% of them obtained from males, 61% of them from Caucasian individuals. The ages of the individuals ranged from 9 to 86 years (mean 30±15.5 years). The characteristics assessed related to age, sex, and race were the following: number and height of the cusps, size of the lunulae, internal and external intercommissural distance, position of the coronary ostium in relation to the aortic valve, position of the ventricular septum in relation to the aortic valve, thickness of the cusps. RESULTS: All hearts assessed had a tricuspidal aortic valve. In regard to the height of the cusps and size of the lunula, the left coronary cusp was larger, followed by the right coronary cusp and the noncoronary cusp. The internal and external intercommissural distances had mean values of 24.6±5.7mm and 19.7±7mm, respectively. In regard to the position of the coronary ostia, in one heart two ostia emerged from the left coronary sinus, and in another, the ostium was supracommissural. The mean diameter of the aorta was 21.8±3.6mm, and there were no significant sexual or racial differences, but the diameter increased progressively with the increase in age. The thickness of the cusps did not show any significant difference in the 3 points assessed. CONCLUSION: The aortic valve annulus did not show a perfect circumference, with some variations in the measurements of the annulus, in the cusps and in the relation with the ventricular septum.

Effects of propranolol on the QT dispersion in congestive heart failure

OBJECTIVE - Studies have shown that therapy with beta-blockers reduces mortality in patients with heart failure. However, there are no studies describing the effects of propranolol on the QT dispersion in this population. The objective of this study was to assess the electrophysiological profile, mainly QT dispersion, of patients with heart failure regularly using propranolol. METHODS - Fifteen patients with heart failure and using propranolol were assessed over a period of 12 months. Twelve-lead electrocardiograms (ECG) were recorded prior to the onset of beta-blocker therapy and after 3 months of drug use. RESULTS - A significant reduction in heart rate, in QT dispersion and in QTc dispersion was observed, as was also an increase in the PR interval and in the QT interval, after the use of propranolol in an average dosage of 100 mg/day. CONCLUSION - Reduction in QT dispersion in patients with heart failure using propranolol may explain the reduction in the risk of sudden cardiac death with beta-blocker therapy, in this specific group of patients.

Exercise and heart failure. Relation of the severity of the disease to the anaerobic threshold and the respiratory compensation point

OBJECTIVE - To identify, the anaerobic threshold and respiratory compensation point in patients with heart failure. METHODS - The study comprised 42 Men,divided according to the functional class (FC) as follows: group I (GI) - 15 patients in FC I; group II (GII) - 15 patients in FC II; and group III (GIII) - 12 patients in FC III. Patients underwent a treadmill cardiopulmonary exercise test, where the expired gases were analyzed. RESULTS - The values for the heart rate (in bpm) at the anaerobic threshold were the following: GI, 122±27; GII, 117±17; GIII, 114±22. At the respiratory compensation point, the heart rates (in bpm) were as follows: GI, 145±33; GII, 133±14; GIII 123±22. The values for the heart rates at the respiratory compensation point in GI and GIII showed statistical difference. The values of oxygen consumption (VO2) at the anaerobic threshold were the following (in ml/kg/min): GI, 13.6±3.25; GII, 10.77±1.89; GIII, 8.7±1.44 and, at the respiratory compensation point, they were as follows: GI, 19.1±2.2; GII, 14.22±2.63; GIII, 10.27±1.85. CONCLUSION - Patients with stable functional class I, II, and III heart failure reached the anaerobic threshold and the respiratory compensation point at different levels of oxygen consumption and heart rate. The role played by these thresholds in physical activity for this group of patients needs to be better clarified.