Diagnostic value of body surface maps in left bundle-branch block.
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Biomedical subjects
Publications and source records attributed to L Favaro.
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The present study has been carried out on 50 patients admitted to C.C.U. for cardiovascular diseases of various ethiology (44 patients with ischemic heart disease) who required antiarrhythmic theory for different types of ventricular arrhythmias: monofocal ventricular extrasistoles greater than 6/min, bigeminal ventricular extrasistoles, polifocal and/or repetitive ventricular tachycardias. The patients have been randomly allocated into two groups of 25 subjects: the first one has been treated with Mexiletine and the second with Lidocaine. In Mexiletine treated group the following results have been obtained: 19 excellent (76%), 4 good (16%) and 2 ineffective (8%). In Lidocaine treated group: 11 excellent (44%), 5 good (20%) and 9 ineffective (36%). Statistical analysis by chi square test has shown significant prevalence of favourable results in Mexiletine treated patients (p less than 0.02; X(2) = 5.33). Moreover, in relation to the type of arrhythmias, Mexiletine succeded in a greater number of cases of complicated ventricular extrasistoles (bigeminal, polifocal and/or ripetitive) and in ventricular tachicardias. Mexiletine also has induced significant reduction of QTc and significant increase of cardiac rate, whereas it did not affect significantly the PR interval and blood pressure. None of these parameters has been influenced significantly by Lidocaine. Side effects have been similar for both drugs and generally mild. On the basis of results and in accord with the electrophysiological properties, the Authors discuss the possible mechanism of action and the role of Mexiletine in the treatment of ventricular arrhythmias particularly those complicating acute phase of myocardial infarction.
30 patients, undergoing coronary angiography for diagnostic and/or bypass surgery evaluation, have been studied also by intracoronary scintigraphy (IS). Scintigraphic and angiographic data have been compared: --21 cases had concordant results: normal in 2 patients (quite normal coronary system); pathological in 19, accounting for a damage both of the principal coronary artery branches and the arteriolar-capillary system: --6 cases had a pathological angiography with a normal IS: an indication of a normal myocardial perfusion; --in 3 cases a normal angiography was coupled with a pathological IS, pointing out a damage of the arteriolar-capillary system. On the basis of these results and of the literature, the AA. emphasize that the IS, allowing an exact evaluation of the myocardial perfusion, complete the essential morphological informations of the coronary angiography and it is specifically useful: --in the candidates to bypass coronary surgery; a viable myocardium is important both for surgery indication and results; --in bypassed patients to assess patency and the actual blood delivery (also for the low reliability of e.v. Thallium); --in patients with typical angina and positive stress test but with normal coronary angiography, to establish an organic lesion of the arteriolar-capillary system.
The effects of Verapamil on main haemodinamic parameters and on Max sigma pos., sigma Q15, Max sigma pos./Max sigma neg. and sigma ST, studied by automatic recording of thoracic maps, were evaluated in 11 patients with acute myocardial infarction within 6 hours from pain onset. Verapamil was given at the dose of 0.1 mg/Kg followed by infusion of 0.035 mg/min. Hemodynamic measurements were made before and 15 minutes after Verapamil; the maps were recorded before and 5, 15 and 30 minutes after Verapamil. Heart rate and sistolic arterial pressure were reduced, though not significantly: right atrial pressure, pulmonary pressures and capillary pulmonary pressure remained unchanged. On the contrary, the reduction of diastolic arterial pressure (from 94 +/- 4.2 to 88 +/- 4.5 mmHg; P less than 0.05) and of cardiac index (from 3.1 +/- 0.11 to 3 +/- 0.11; P less than 0.05) was important. Max sigma pos. increased after 15 minutes from 11619 +/- 1970 to 12349 +/- 2151 microV (P less than 0.01), but il decreased after 30 minutes to 11037 +/- 2042 microV (P less than 0.05). Max sigma pos./Max sigma neg. ratio increased significantly after 5 and 15 minutes. Sigma Q15 increased significantly only after 30 minutes (from 7198 +/- 1643 to 8688 +/- 1541 microV; P less than 0.05). Sigma ST showed a transient, non significant increase after 5 minutes, but decreased significantly after 30 minutes (from 76664 +/- 19505 to 67157 +/- 18581 microV; P less than 0.05). The results show that Verapamil does not cause worsening of main haemodinamic parameters during acute, non complicated myocardial infarction and reduces significantly ST segment elevation. The Authors discuss also a possible electrophysiological effect of Verapamil on action potential of ischemic cells, responsible for early increase of sigma ST observed in some patients.
MB isoenzyme of creatine kinase was measured every 3 hours during the first 24 hours of admission to C.C.U. and successively every 4-6 hours in the next 24-48 hours in 42 patients with acute transmural myocardial infarction. The pain-C.C.U. admission time interval was less than 6 hours in all cases. 22 patients were treated by propranolol (2 mg bolus followed by 0.1 mg/Kg/die for the next 48 hours in continuous i.v. infusion), 20 patients served as a control. Cumulated activity, peak plasma value, rate of release and total duration of release of MB-CK did not differ significantly between the two groups. In patients treated within 3 hours from pain onset (n = 12) cumulated activity, peak plasma value and rate of release of MB-CK were significantly inferior than control group. In patients treated between the 3rd and 6th hour from pain onset (n = 10) the total duration of release of isoenzyme was significantly prolonged. No treated patients developed clinical or radiologic signs of cardiac insufficiency. The incidence of ventricular arrhythmias was 17% in the treated group vs. 62% in the control group (P < 0.05). The data show that propranolol, if started early in the course of acute myocardial infarction, reduces significantly infarct size and slows down the evolution of necrotic process.
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Two cases of isolated anomalous origin of the left circumflex coronary artery from the right Valsalva sinus are described. In contrast with all the cases reported in the literature, both our female patients had typical angina; in one case, moreover, in coincidence with the precordial pain there were significant alterations of the repolarization, also caused by stress testing with the bicycle ergometer. On the basis of these findings, the authors believe that in patients with this anomaly the angina might be produced through a sharp decrease in the circumflex coronary artery blood flow correlated with caliber changes of the aorta.
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BACKGROUND: The finding fo false fixed 201Tl defects by the conventional stress-redistribution protocol is a well-known phenomenon. The aim of this study was to compare two different 201Tl reinjection protocols to identify viable myocardium in the same group of patients. METHODS AND RESULTS: Twenty-seven patients with ischemic heart disease and at least one persistent defect on 201Tl uptake redistribution images 3 hours after stress were investigated. In the same-day protocol (R1) patients were reinjected with 1 mCi 201Tl immediately after redistribution images, with imaging starting 15 minutes later; in the different-day protocol the patients were reinjected with 2 mCi 48 to 96 hours later. Two sets of images were obtained, 30 (R2) and 180 (R3) minutes after reinjection. The comparison of redistribution and reinjection versus stress images showed a significant (p < 0.01) frequency distribution. The uptake of 201Tl of the 111 irreversible segments at redistribution was enhanced in 35.1% with R1, 43.2% with R2, and 49.5% with R3. The agreement among the three procedures in classifying the segmental defects was high between R2 and R3 (r = 0.81) and lower between the same- and different-day protocols. Of the 19 patients with a dominant scar pattern demonstrated by the conventional stress-redistribution study, 37%, 47%, and 53% were judged mainly ischemic after R1, R2, and R3, respectively. All but three of the 55 segments-showing an increased 201Tl uptake by R3 had an echocardiographic score of 2 or greater. CONCLUSION: The best technique to differentiate scarred from viable myocardium seems to be the reinjection of a second dose of 201Tl on a different day followed by imaging 3 hours later.
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