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Biomedical subjects

C Marcassa

Publications and source records attributed to C Marcassa.

At least 55 records · Page 3Linked to original sources
PubMed1991

Right coronary artery disease. Pathophysiology, clinical relevance, and methods for recognition.

Among the clinical manifestations of ischemic heart disease, right coronary artery (RCA) disease offers a wide variety of right and left ventricular ischemic involvement, including prevalent right ventricular dysfunction and severe cardiac failure. Whether the right ventricular impairment is dependent primarily on ischemia of the right ventricle or requires a concomitant left ventricular dysfunction remains debatable. To assess the pathophysiology and clinical relevance of RCA-related ischemia, a systematic study of patients with single RCA disease (either vasospastic angina at rest or typical stable angina) was undertaken by radionuclide ventriculography. A high incidence of ischemia-induced right ventricular dysfunction was observed (93% and 95% in angina at rest and on effort, respectively), either alone or associated with left ventricular impairment. These results were compared with those obtained in a control population with isolated left anterior descending artery disease and either primary or secondary angina pectoris. We infer that the impairment of the right ventricle was related primarily to right ventricular ischemia and that left ventricular dysfunction alone did not cause an important depression of right ventricular systolic function. In conclusion, the clinical manifestations of RCA disease can be protean; the right ventricle can be the target of ischemia, and recognition of its impairment poses diagnostic problems. Radionuclide ventriculography and two-dimensional echocardiography, together with stressors of coronary flow reserve, are reliable techniques for assessing RCA-related ischemia.

Angina Pectoris↗
PubMed1990

Behavior of right and left ventricles during episodes of variant angina in relation to the site of coronary vasospasm.

The effects of single-vessel coronary occlusion on simultaneously evaluated right (RV) and left ventricular (LV) performance were assessed and compared with LV perfusion patterns in 25 patients with variant angina. Coronary spasm involved the right coronary artery in 15 patients (group 1) and the left anterior descending coronary artery in 10 patients (group 2). Biventricular function was assessed by radionuclide angiography under basal conditions, during spontaneous or ergonovine-induced ischemia, and after resolution of the ischemic attack. Myocardial perfusion was assessed by thallium 201 scintigraphy in 21 patients of this series during superimposable ischemic episodes. In group 1, ischemia caused RV (14 of 15 patients) and LV (13 of 15 patients) regional dysfunction with significant reduction in RV and LV ejection fractions. The interventricular spetum was involved in six of 15 patients, causing a more pronounced LV impairment. In group 2, all patients showed septal dyssynergies associated with a reduction of LV ejection fraction; absent or trivial RV involvement was observed. In both groups, LV perfusion defects were present in all patients with LV wall motion abnormalities during ischemia, matching the site of regional dyssynergies. Thus, in a group of patients with variant angina and single-vessel disease, transient occlusion of the right coronary artery directly caused RV and LV impairment; in these patients, the extent of LV but not RV dysfunction appeared related to the presence of septal ischemia. Vasospasm of the left anterior descending coronary artery consistently caused LV dysfunction not associated with secondary effects on RV systolic function.

Angina Pectoris, Variant↗
PubMed1990

A new method for noninvasive quantitation of segmental myocardial wall thickening using technetium-99m 2-methoxy-isobutyl-isonitrile scintigraphy--results in normal subjects.

A quantitative index of regional myocardial wall motion obtained from electrocardiogram-gated perfusion images has been assessed. The assumption for the proposed algorithm is that, according to the partial volume effect, the recovery counts by the instrumentation is a function of the object size. Systo-diastolic changes in the detected radioactivity would therefore reflect changes in myocardial wall thickness. Ten normal volunteers were studied in control condition by 99mTc 2-methoxy-isobutyl-isonitrile scintigraphy. Electrocardiogram (ECG)-gated images were acquired in multiple projections. End-diastolic and end-systolic activity was measured along radii from the center to the edge of the left ventricle. Data are displayed as circumferential profiles and the percent systolic thickening determined according to the formula (end-systolic profile--end-diastolic profile) (end-diastolic profile + background) x 100.) The intra- and interobserver variabilities were +/- 5.4% and +/- 4.1%, respectively. Analysis of regional systolic thickening showed a heterogeneous pattern, with a maximal and minimum value of 35% and 27% located to the infero-apical and to the proximal anterior wall, respectively. Our values correlate well with those reported for normals using cine computed tomography or nuclear magnetic resonance.

Adult↗
PubMed1989

Multiparametric approach to diagnosis of non-Q-wave acute myocardial infarction.

The present study investigated whether the lack of enzyme increase is reason enough to exclude necrosis in patients with ischemic heart disease who develop electrocardiographic sustained ST-T changes in the absence of Q waves. In 15 consecutive patients with angina who developed sustained ST-T changes during hospitalization, the presence of myocardial necrosis was investigated by a prospective multiparametric approach. Serum enzymes and myoglobin, pyrophosphate uptake, 2-dimensional echocardiography, perfusion scintigraphy, left ventriculography and coronary angiography were evaluated. According to creatine kinase and creatine kinase-MB peak at twice the upper normal value, the diagnosis of acute myocardial infarction applied only to 40% of patients. However, myoglobin was positive in 80% and a perfusion defect could be documented by an electrocardiographic gated microsphere technique in 100% of patients. The positivity of myoglobin increased to 100% and of creatine kinase and creatine kinase-MB to 87 and 60%, respectively, when a peak value twice the individual lowest value was considered for positivity. The 100% presence of perfusion defects associated with the high prevalence of both positive pyrophosphate uptake (87%) and regional dyssynergies (87 and 73%, respectively, by left ventriculography and echocardiography) strongly suggest that sustained (greater than or equal to 7 days) ST-T changes in this population were indicative of myocardial necrosis. Thus, by conventional enzymatic approach, diagnosis of non-Q-wave infarction can be missed in a sizable number of patients and present important clinical implications.

Adult↗
PubMed1988

Frequent occurrence of silent ischaemia in patients with isolated right coronary artery stenosis: a radioisotopic study.

Silent ischaemia has been widely investigated limiting the diagnostic approach to the left ventricle. To date, no systematic study on silent ischaemia in patients with demand-induced right ventricular dysfunction has been reported. The occurrence of painless ischaemic episodes was evaluated by atrial pacing and radionuclide angiography in 20 consecutive patients with single right coronary artery stenosis and without previous myocardial infarction. At the peak pacing rate all patients showed transient myocardial dysfunction (reduction of ejection fraction and/or development of wall-motion abnormalities) localized to the right, the left, or to both ventricles in 9, 1 and 10 patients, respectively. Eight patients experienced chest pain (group 1) and 12 were asymptomatic (group 2) at the maximal pacing rate. Basal left ventricular ejection fraction (55 +/- 4% vs. 55 +/- 5%), basal right ventricular ejection fraction (48 +/- 4% vs. 46 + 8%), peak pacing left (52 +/- 9% vs. 50 +/- 11%) and right (38 +/- 7% vs. 37 +/- 9%) ventricular ejection fractions, and maximal pacing pressure rate product (17,289 +/- 2880 vs. 19,244 +/- 3806) were not significantly different in the two groups. This study demonstrates a high prevalence of silent ischaemia in patients with single right coronary artery stenosis and pacing-induced dominant right ventricular dysfunction. Painful episodes do not appear to be related to the magnitude of changes in ejection fraction.

Coronary Disease↗
PubMed1988

[Right ventricular dysfunction in demand-induced ischemia in patients with isolated right coronary artery disease: a radioisotope study].

In ischemic heart disease, the left ventricle has been considered the main target of an imbalance between myocardial oxygen supply and demand. Accordingly, the approach to ischemia has been directed at the evaluation of the left ventricle. The aim of this study was to assess the relative involvement of the left and right ventricle in patients with isolated right coronary artery stenosis. We studied 20 patients with a clinical history of effort angina (15 male, 5 female, mean age 54.1 +/- 6.2) using radionuclide angiography and atrial pacing. Findings were compared with those of 6 normal subjects that were paced at the maximal heart rate of 150 beats/min. Atrial pacing was interrupted because of diagnostic ST segment depression in 8 patients, Wenckebach type atrioventricular block in 1, chest pain without electrocardiographic changes in 4 and the achievement of the maximal prefixed heart rate of 150 beats/minute in 7. With respect to control conditions, during atrial pacing right ventricular ejection fraction declined from 46.8 +/- 6.8% to 37.4 +/- 8.1% (p less than 0.001), while no significant change was observed in left ventricular ejection fraction values (55.2 +/- 4.5% and 51.1 +/- 10.2% respectively). During atrial pacing, left ventricular peak filling rate increased from 1.77 +/- 0.53 to 4.71 +/- 1.8 end-diastolic volumes/second (p less than 0.0001). Qualitative analysis of regional wall motion showed a right ventricular dysfunction in 19/20 patients; this was prevalent in 9 and involving also the left ventricle in 10; an isolated impairment of the left ventricle was observed in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Role of myocardial scintigraphy with thallium-201 in the characterization of episodes of transient ischemia at rest. Clinical and electrocardiographic correlates].

UNLABELLED: In the past ten years we studied 80 patients with angina at rest by 201-Thallium perfusion scintigraphy. According to ECG changes during episodes of transient ischemia at rest, the patients were divided into three groups. Thirty six patients showed transient ST segment elevation (Group 1); 33 ST segment depression (Group 2) and 11 normalization of negative T waves (Group 3). 201-TI scintigraphy was performed during spontaneous or ergonovine induced episodes of ischemia and at redistribution. Group 1 showed localized and severe perfusion defects, well correlated to the site of ECG changes. Group 2 showed more diffuse and less severe perfusion defects, less correlated to the site of ECG changes. Group 3 showed perfusion defects similar to those observed in Group 1 and associated in 54% with basal perfusion defects due to previous myocardial infarction. IN CONCLUSION: A) three main perfusion patterns are associated with the three types of ECG changes; B) relative to ECG, myocardial scintigraphy provides a more accurate definition of the site and extension of ischemia, particularly in Group 2 patients.

Adult↗
PubMed1986

Clinical application of monitoring techniques: radioisotopic methods.

The availability of mobile gamma cameras or the nearness of nuclear medicine devices to the coronary care unit make the assessment of transient myocardial ischemia by radioisotopic techniques practical. Nuclear cardiology provides information on the presence, site and extent of ischemia and helps the clinician in the evaluation of myocardial functional impairment and recovery. Monitoring of myocardial wall motion by radionuclide ventriculography demonstrates that during angina at rest; global ejection fraction is not always sensitive to regional ischemia; episodes of angina with undetectable electrocardiographic signs of ischemia can be associated with severe myocardial dysfunction; separate left and right phase analysis of radionuclide ventriculography is a sensitive tool to assess segmental dyssynergy localized to the left or the right ventricle; a prevalent right ventricular impairment during ischemia, not measurable by Thallium scintigraphy, is possible; the recovery of function after ischemia is usually fast and apparently complete. In addition, useful diagnostic information can be derived by left ventricular injection of radioactive microspheres during cardiac catheterization followed by gated acquisitions of the intramyocardial radioactivity. Gated microsphere acquisitions, providing diastolic and systolic images, avoid blurring of images due to cardiac motion and enhance contrast between myocardium and background: the overall result is an improved detection and definition of small perfusion defects. Furthermore, this technique permits simultaneous assessment of regional perfusion and wall motion. An appraisal of potential mismatches between flow and function after revascularization procedures can be recognized by this approach. The development of technology is improving the performance of nuclear medicine instrumentation, hampered, at present, by limited spatial and temporal resolution.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1986

When the electrocardiogram fails to define site and extent of myocardial ischemia.

Information on the anatomical site of myocardial ischemia and infarction is commonly derived from the 12-lead electrocardiogram; however, correspondence between an electrocardiogram lead, showing ischemic changes and actual location of ischemia is not always present. In our experience, a good correspondence between the electrocardiogram and perfusion defects was found in patients with angina at rest and anterior ST segment elevation or normalization of negative T wave while patients with transient ST segment depression showed perfusion defects which correlated less with electrocardiographic changes. In addition, patients with ischemic episodes at rest and with inferior ST segment elevation, right or left ventricular ischemia were indistinguishable on the basis of the electrocardiogram as documented by Thallium-201 scintigraphy and radionuclide ventriculography. In effort angina, the site and extension of ST segment depression, even in patients with single vessel disease, failed to localize the actual anatomical location of myocardial ischemia. In patients with persistent ST segment depression and/or negative T waves, and clinically documented myocardial necrosis, transmural and non-transmural persistent perfusion defects were found in spite of absence of Q waves. In these patients, late normalization of the electrocardiogram did not correspond to normalization of flow. In conclusion, electrocardiographic changes do not always provide correct information regarding the presence, location and extent of myocardial ischemia and a multiparametric approach is often required in order to characterize ischemic and/or necrotic areas.

Angina Pectoris↗
PubMed1982

[Cold adaptation and changes in peroxisome enzyme in various organs of the rat].

In the rat brown fat peroxisomes - thermogenetic organules - an peroxisomal enzyme activities undergo remarkable changes during the adaptation to cold of the animals (see 3). In this paper was show that changes of peroxisomal enzyme activities occur also in liver and kidney during cold-adaptation. Catalase, L-hydroxyacid oxidase, uricase and D-aminoacid oxidase (DAO) were assayed as in (6). During cold-adaptation, the activity of the former three enzymes (Table 2) increases with the weight of the organs (Table 1) whereas that of DAO exhibits a much larger increase (Table 3). Results are discussed with regard to the contribution of the liver to non-shivering thermogenesis.

Adaptation, Physiological↗
PubMedDate not supplied

Transient left ventricular dilation at quantitative stress-rest sestamibi tomography: clinical, electrocardiographic, and angiographic correlates.

BACKGROUND: Few data are available regarding the incidence and significance of transient left ventricular (LV) dilation on stress sestamibi single photon emission computed tomography (SPECT), which is different from thallium-201 studies because images are acquired late after tracer injection. METHODS: We studied 234 patients with ischemic heart disease and interpretable electrocardiograms undergoing stress-rest sestamibi SPECT on separate days. Sestamibi uptake defect extent was quantified on SPECT polar maps. Epicardial and endocardial transient dilation indexes (TDI) were also calculated. RESULTS: According to our normal TDI values, 148 patients (63%) had no dilation and 86 patients (37%) had abnormal endocardial TDI; a global LV dilation (abnormal endocardial and epicardial TDI) was observed in 19 patients (8%). ST-segment depression was more frequent in patients with transient LV dilation (55%) than in those without (36%; P < .01), as were the extent of stress hypoperfusion (13% +/- 12% vs 6% +/- 7% in patients with no dilation; P < .001) and the angiographic severity score (11.4 +/- 5.9 vs 9.2 +/- 3.7; P < .05). At multivariate analysis, stress hypoperfusion was the sole predictor of transient LV dilation. CONCLUSIONS: Transient LV cavity dilation is frequent on stress sestamibi SPECT. Ventricular cavity dilation is more common than global dilation and suggests subendocardial ischemia. It is related to a greater amount of jeopardized myocardium and is strongly associated with electro-cardiographic signs of ischemia.

Case-Control Studies↗
PubMedDate not supplied

Electrocardiographic evolution after Q-wave anterior myocardial infarction: correlations between QRS score and changes in left ventricular perfusion and function.

BACKGROUND: In the thrombolytic era, conflicting data have been reported on the usefulness of the QRS score in estimating the amount of left ventricular (LV) damage after acute myocardial infarction (MI). METHODS AND RESULTS: We correlated the QRS score with the extent of LV hypoperfusion and ejection fraction (EF) in 95 consecutive male patients with a first anterior Q-wave MI; the 6-month evolution of QRS score and changes in LV perfusion and function were also compared. The Selvester-Wagner QRS score was computed from the digitized 12-lead electrocardiogram, both at predischarge and 6 months later; at the same time, resting sestamibi first-pass ventriculography and single photon emission computed tomography imaging were performed. A reduction in QRS score occurred at 6 months (6.7 +/- 3.4 vs 7.8 +/- 2.9 at predischarge; P <.001); the perfusion defect extent also decreased (P <.01), and LV EF improved (P <.05). At predischarge, no correlation was found between QRS score and hypoperfusion extent or EF; in contrast, a weak correlation was observed 6 months later (r = 0.55; P <.001; and r = 0.48; P <.01, respectively). QRS score changes from predischarge to 6 months showed limited accuracy in predicting clinically meaningful changes of perfusion or EF (receiver operating characteristic area under the curve, 0.58 and 0.61, respectively). Thrombolytic therapy did not influence the relationship between QRS score and scintigraphic findings. CONCLUSIONS: In patients with recent anterior Q-wave MI, QRS scoring showed a weak, delayed correlation with the amount of LV damage, as estimated by radionuclide techniques. Spontaneous changes in QRS score from predischarge to 6 months seem to be of limited value in identifying patients with late improvement in LV perfusion and function.

Adult↗