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Biomedical subjects

A Maseri

Publications and source records attributed to A Maseri.

At least 397 records · Page 22Linked to original sources
PubMed1980

Xenon studies of myocardial blood flow: theoretical, technical, and practical aspects.

External detection by a single collimator of the washout curve of 133Xe following its intracoronary injection was used in humans following its validation in animals. However, additional experimental studies showed that the straightforward application of the theoretical principles on which the technique should be based resulted in uncorrected values. Special empirical modifications in the analysis of the washout curves were required in order to obtain a fair agreement between calculated and experimental flow values. Furthermore, studies in humans indicate that reappearance of indicator into the counting field due to recirculation and diffusion retention of the tracer in epicardial fat alter the precordial washout curve leading to underestimation of coronary blood flow. This method has found a second wave of applicatin in humans for the study of regional myocardial perfusion using a gamma camera. The amount of new information on regional myocardial perfusion provided by this approach is quite considerable; however, the interpretation of the values obtained in these studies requires particular attention in view of the limitations outlined above.

Animals↗
PubMed1980

Thallium-201 scintigraphy for diagnosis of old myocardial infarction: comparison with electrocardiographic, ventriculographic, and coronary arteriographic findings.

Myocardial scintigraphy with 201Tl was performed at rest in a selected group of 36 patients with unequivocal clinical and electrocardiographic evidence of old myocardial infarction. The scintigraphic findings were correlated with electrocardiographic pattern, and with regional left ventricular wall motion and the severity of coronary artery disease defined by contrast angiography. Detection was dependent on the extent of the infarct but was independent of QRS morphology and of the severity of coronary disease. When positive, 201Tl scintigraphy was often a more precise method than the electrocardiogram for localising and delineating the extent of the infarct. Furthermore, the perfusion defect corresponded in location and extent to abnormalities of left ventricular wall motion. The site or severity of coronary artery disease could not be determined from the 201Tl scintigram.

Adult↗
PubMed1980

Sequence of events in angina at rest: primary reduction in coronary flow.

To investigate the events that lead to acute myocardial ischemia we monitored continuously the ECG, the left ventricular (four patients) or aortic (two patients) pressure and the great cardiac vein oxygen saturation (CSO2S) by a fiberoptic catheter in six patients with frequent anginal attacks at rest. We recorded 137 transient ischemic episodes (10 with chest pain) characterized by ST-segment elevation in 28 episodes, depression in three episodes and by pseudonormalization of previously inverted or flat T waves in 106 episodes. The onset of electrocardiographic and hemodynamic changes was preceded by a large drop in CSO2S in all 135 episodes with ST-T changes in the anterior leads but not in two episodes with ST elevation on inferior leads. The fall in CSO2S, consistently followed by signs of left ventricular function impairment and never preceded by any detectable increase in the hemodynamic determinants of myocardial oxygen consumption, probably reflects a reduction in regional perfusion. Thus, a reduction in coronary flow may cause transient ischemia in patients with angina at rest. These episodes may be associated with variable, often minor electrocardiographic changes and occasionally with anginal pain.

Adult↗
PubMed1980

[Hemodynamic effects of dobutamine in patients with severe low-output heart failure (author's transl)].

We studied the hemodynamic effects of dobutamine in 10 patients with severe chronic heart failure due to congestive cardiomyopathy in 5, to ischemic heart disease in 4 and to hypertensive cardiomyopathy in 1. Dobutamine was injected during three periods of 30 min each alternated with equal periods of placebo at doses of 2,5-5 and 7,5 mcg/Kg/min respectively. The most favorable hemodynamic effects, obtained at an infusion rate of 5 mcg/Kg/min, was characterized by a significant inn 4 and to hypertensive cardiomyopathy in 1. Dobutamine was injected during three periods of 30 min each alternated with equal periods of placebo at doses of 2,5-5 and 7,5 mcg/Kg/min respectively. The most favorable hemodynamic effects, obtained at an infusion rate of 5 mcg/Kg/min, was characterized by a significant increase of the cardiac index and of the left ventricle stroke work index, accompanied by a significant decrease of the left ventricular filling pressure and of the systemic and pulmonary vascular resistance. The hemodynamic monitoring showed that the pharmacological effects of the drug subsided about 5-10 min after the interruption of infusion. At the infusion rate of 7,5 mcg/Kg/min we observed a significant increase of premature ventricular beats in 3 patients. We conclude that dobutamine at the dose of 5 mcg/Kg/min shows a powerfull positive inotropic action not accompanied by apparent side effects.

Adult↗
PubMed1980

[Low reliability of ECG monitoring in CCU for detection of ischemic episodes (author's transl)].

In 10 patients with frequent anginal attacks admitted to CCU, 2-lead ECG Holter monitoring (H-M) was performed for a total of 10 days. The number of ischemic episodes detected by retrospective analysis of H-M was compared with the number detected on the basis of symptoms and continuous visual ECG monitoring in CCU (CCU-M) by highly trained staff. A total of 157 episodes was identified by H-M [82 ST elevation (ST), 15 ST depression (ST) and 60 t wave changes]. Only 15 of these episodes were detected by CCU-M (13 ST, 1 ST and 1 T wave changes) of which 12 were symptomatic. When 6 H-M ECGs were simultaneously displayed on an oscilloscope in real-time (as in CCU-M), one of the Authors was able to detect only 36% of the episodes, whereas the frequency reached 80% when the analysis was limited to one tape at the time. The results show the low reliability of the CCU-M in detecting ischemic attacks; this appears mainly related to the display of multiple tracings.

Angina Pectoris↗
PubMed1980

[Analysis of Holter monitoring for detection of myocardial ischemia episodes (author's transl)].

While the use of the 24 hour Holter monitoring for the detection of the cardiac arrhythmias and conduction disturbances is well established, its applicability to the monitoring of the ST segment and T wave for the detection of myocardial ischemia is controversial. For these reasons the Holter monitoring is mainly confined to the detection of cadiac arrhythmias and is used in those centers where computer facilities are available. We proposed to record the electrocardiographic tape replayed at 60 times the real time on a direct recording ultraviolet oscillograph running at low speed obtaining a fast compact analogue representation of the Holter recording where the 24 hour Holter recording is compressed into cm 480 of paper. The analogue compact representation described allows an easy detection of the transient displacement of the ST segment and/or changes in the T wave amplitude and direction and/or QRS pattern all due to myocardial ischemia without the use of any expensive computer facilities.

Coronary Disease↗
PubMed1979

Management of unstable angina at rest by verapamil. A double-blind cross-over study in coronary care unit.

A therapeutic trial with verapamil, a calcium-antagonist drug, was performed in 12 patients admitted to our coronary care unit because of frequent daily attacks of angina at rest attributed to coronary vasospasm. After a 48-hour run-in period, oral verapamil 480 mg/day and placebo were administered alternately during 4 randomised 48-hour periods. Transient ischaemic attacks with ST segment elevation or depression, with or without pain, were documented by continuous electrocardiographic monitoring. The number of attacks during the run-in and 2 placebo periods were 128, 123, and 130, respectively, and 31 and 23 during the 2 treatment periods (P less than 0.006 and P less than 0.003). This drug therefore appears to be effective in the management of patients with frequent attacks of angina at rest.

Adult↗
PubMed1978

Coronary vasospasm as a possible cause of myocardial infarction. A conclusion derived from the study of "preinfarction" angina.

To investigate the pathogenesis of myocardial infarction we undertook a systematic study of patients with angina at rest, a syndrome known to evolve frequently into infarction. Among 187 consecutive patients, 37 had infarction, all in the area that showed electrocardiographic changes during angina. In all 76 patients who underwent hemodynamic monitoring, 201thallium myocardial scintigraphy or angiography during angina, a vasospastic origin of the attacks was documented. In six patients with infarction shortly after these studies and in two in whom the infarction developed during hemodynamic monitoring or during angiography the onset of infarction was indistinguishable from the onset of anginal attacks. One patient in whom spasm was observed at the onset of infarction died six hours later; at post-mortem examination, a fresh laminar thrombus was found at the site of the spasm. After infarction, complete thrombotic occlusion of the branch shown to undergo vasospasm was documented in two patients by angiography.

Adult↗