Search PubMed⌕ Search

Biomedical subjects

M Previtali

Publications and source records attributed to M Previtali.

At least 73 records · Page 4Linked to original sources
PubMed1985

Medical and surgical treatment of sustained and recurrent post-infarction ventricular tachycardia.

Over a five-year period 57 patients (pts) with sustained, recurrent, post-infarction ventricular tachycardia (VT) refractory to conventional antiarrhythmic treatment were evaluated. In 28 (49%) pts VT was controlled by amiodarone (A) in a dose of 3000 mg week-1. During long-term follow-up 5/28 (18%) pts died; no severe side-effects were observed with this dosage. In 17 of the 29 pts not controlled by this regimen, the dosage of A was increased to 6000-8000 mg week-1; short-term control of VT was achieved in 9/17 (53%) pts, but over a long-term follow-up 5/9 (56%) died and severe side-effects (11% pulmonary fibrosis and 11% hepatitis) occurred in 22%. Twenty pts, resistant to a low (12 pts) or high (8 pts) doses of A, underwent map-guided surgical treatment. In conclusion A is superior to conventional drugs in the treatment of sustained, recurrent, post-infarction VT, but when high doses are necessary to prevent VT, long-term results are poor and severe side-effects frequent. In pts refractory to standard doses of A, map-guided surgery is the treatment of choice.

Adult↗
PubMed1985

Occlusion and reperfusion as possible different mechanisms of ventricular tachyarrhythmias in Prinzmetal's variant angina.

A case of a patient with variant angina associated with severe ventricular tachyarrhythmias studied by continuous electrocardiographic and haemodynamic monitoring is reported. Severe ventricular arrhythmias developed both during maximal ST-segment elevation, in association with haemodynamic signs of acute ischaemic cardiac dysfunction and after nitroglycerin-induced reversion of ischaemia and return of the haemodynamic variables to the basal state. Thus, in this patient, ventricular arrhythmias during acute ischaemia could be related not only to acute vasospastic coronary occlusion but probably also to reperfusion after relief of coronary spasm.

Angina Pectoris, Variant↗
PubMed1985

[Intravenous and oral encainide: electrophysiological effects in patients with paroxysmal reciprocating supraventricular tachycardia].

The electrophysiologic effects of encainide (E) after acute i.v. (1 mg/kg in 60') and oral administration (75 to 150 mg/die for 48-72 h) were evaluated in 10 pts with PSVT (5 men and 5 women, mean age 48 +/- 15 years). The mechanism of PSVT was related to a reentry through an accessory A-V pathway in 6 cases while in the other 4 the reentry was confined in the A-V node. PA, AH and HV intervals lengthened from 42.8 +/- 5.1, 77.8 +/- 19.7 and 38.3 +/- 6.6 msec to 50 +/- 13.5, 91.7 +/- 22.9 and 49.4 +/- 12.9 and to 48.3 +/- 7.1, 94.4 +/- 33.9 and 44.4 +/- 9.2 msec, after i.v. and oral E respectively. Atrial and ventricular refractory periods showed slight not significant variations. Wenckebach point lengthened from 316 +/- 28 msec to 354 +/- 32 and to 359 +/- 45 msec, after i.v. and oral E respectively. Tachycardia cycle length was 358 +/- 32 msec in basal conditions. After i.v. E tachycardia was inducible only in 6 cases, with a mean cycle length of 403 +/- 48 msec. After oral E tachycardia was reproduced only in 3 patients with a mean cycle length of 433 +/- 85 msec. Nine patients were treated chronically with E, at a mean dose of 89 +/- 36 mg/day. After a follow-up of 18 +/- 8 months, tachycardia recurred but with a marked reduction of the attacks, in 3 patients; only 3 patients complained of side effects (blurred vision). Thus E is highly effective in the prevention of PSVT; the drug seems well tolerated thanks to the low dosage required for the control of PSVT.

Administration, Oral↗
PubMed1985

[Multiplexed peroperative mapping in unstable rhythm disorders].

Since the introduction and development of mapping methods in clinical practice, some arrhythmias can now be treated surgically. We studied an automatized method of epicardial mapping necessitating only a single ventricular complex for the definition of epicardial activation; the signal was acquired from 35 monopolar electrodes spread out over the whole of the ventricular epicardium or concentrated in the zone of epicardial break through to localise its site more accurately. The acquisition, elaboration and tracing of these maps were performed with a computer; the activation can be presented as isochrones or isopotentials. The main value of this method of automatic mapping is the possibility of studying irregular arrhythmias whose potentials are difficult to obtain beat manually. This method has already been applied to 21 patients with ventricular tachycardia unresponsive to medical treatment and referred for surgery.

Arrhythmias, Cardiac↗
PubMed1984

Dihydroquinidine versus disopyramide: efficacy in patients with chronic stable ventricular ectopy.

Dihydroquinidine (DQ) is contained in substantial amounts in quinidine salts, but its direct antiarrhythmic action has not been studied. The efficacy of oral DQ (300 mg t. i. d.) compared to disopyramide (D) (200 mg t.i.d.) was thus investigated using a double-blind crossover placebo-controlled protocol in 12 patients, aged 13 to 67 years, with chronic stable high frequency premature ventricular beats (PVB), defined as greater than 100 PVB/h during 48-72-h control Holter monitoring. The protocol included three 72-h treatment periods: DQ, D, and placebo at random. On days 2 and 3 of each period a 24-h Holter recording was carried out; drug blood levels were determined at peak (days 2 and 3) and trough time (day 3). No significant difference in the mean PVB/h was found between control (735 +/- 400) and placebo periods (564 +/- 388), or between the two Holter recordings of each period. Compared to placebo both DQ (106 +/- 113, p less than 0.005) and D (240 +/- 263, p less than 0.05) reduced the mean PVB/h, but the decrease was significantly higher with DQ (78 versus 53%, p less than 0.02). Nine patients (75%) on DQ and 5 (42%) on D had a greater than 70% decrease in mean PVB/h; complex PVBs were abolished in 3 of 6 patients on both treatments. On day 3, DQ plasma levels were 1.31 +/- 0.44 (peak) and 0.92 +/- 0.45 (trough) mg/l; D plasma levels were 2.88 +/- 0.64 (peak) and 2.02 +/- 0.31 (trough) mg/l; no significant difference was found between day 2 and day 3 samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Ventricular tachyarrhythmias in Prinzmetal's variant angina: clinical significance and relation to the degree and time course of S-T segment elevation.

Fifty-six patients with active Prinzmetal's variant angina were studied to determine the incidence and clinical significance of ventricular tachyarrhythmias and the correlation between arrhythmias and degree and time course of S-T segment changes during the ischemic attacks. Twenty-nine patients (Group I) had no ventricular arrhythmias in any of the 1,083 recorded episodes, while 27 patients (Group II) developed arrhythmias in 18% of the attacks. No significant differences in clinical, electrocardiographic, angiographic, or hemodynamic findings could be found between the 2 groups. In 23 of the 27 Group II patients, ventricular arrhythmias developed during maximal S-T segment elevation (occlusion arrhythmias), while in 10 they occurred during resolution of S-T segment changes (reperfusion arrhythmias); 6 of the latter patients also had occlusion arrhythmias. Eight of the 23 patients with occlusion arrhythmias and 6 of the 10 with reperfusion arrhythmias had ventricular fibrillation or ventricular tachycardia. Maximal S-T segment elevation was significantly greater (p less than 0.001) in patients with occlusion arrhythmias than in those without arrhythmias. The episodes with reperfusion arrhythmias were significantly longer (p less than 0.001) and showed a significantly greater S-T segment elevation (p less than 0.001) than those without arrhythmias in Group I patients. This study shows that significant ventricular tachyarrhythmias develop during ischemic attacks in about 50% of patients with active variant angina; clinical and angiographic features are not useful in distinguishing patients with arrhythmias from the others. Our findings suggest that in variant angina ventricular arrhythmias may be due to the effects of both coronary artery occlusion and reperfusion; both types of arrhythmias are correlated with the severity of ischemia, as measured by the degree of S-T segment elevation. Reperfusion arrhythmias also appear to be correlated with the duration of ischemia.

Adult↗
PubMed1983

Efficacy, duration and mechanism of action of nifedipine in stable exercise-induced angina pectoris.

The duration of effect of single oral doses of 10 and 20 mg of nifedipine was studied in 10 patients with angiographically proven coronary artery disease and with stable exercise-induced angina pectoris. In a randomized double-blind manner exercise tests were carried out 1 hour before and 1, 2, 4 and 6 h after the administration of placebo, nifedipine 10 mg(N10) and nifedipine 20 mg(N20). Compared with the placebo both N10 and N20 produced a statistically significant increase in exercise tolerance at 1(P less than 0.05), 2(P less than 0.01), 4(P less than 0.01) and 6(P less than 0.05) hours after N10 and at 1(P less than 0.01), 2(P less than 0.01), 4(P less than 0.01) and 6(P less than 0.05) hours after N20. At peak exercise the product of heart rate X systolic blood pressure (RPP) was significantly increased compared with placebo at 2, 4 and 6 h after N10 and at 2, 4 and 6 h after N20 with maximal ST-segment depression unchanged. At the same duration of exercise at which angina had occurred during control studies the RPP was unaffected by nifedipine while a statistically significant reduction of ST-segment depression was seen at 1, 2 and 4 h after N10 and at 1, 2 and 4 h after N20. Direct measurements of great cardiac vein flow during exercise in two patients showed that nifedipine is effective in preventing the abnormal increase of exercise-induced coronary tone in the area supplied by stenotic vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Post-infarct ventricular tachycardia. Electrophysiological aspects, endocardial and epicardial electromapping and surgical therapy].

Seven patients (6 men and 1 woman), aged 45-67 years, with previous myocardial infarction and recurrent sustained ventricular tachycardia (VT), refractory to medical treatment, underwent encircling endocardial ventriculotomy, according to a modified Guiraudon's technique, associated with surgical resection of ventricular aneurysm. Before surgery all patients underwent electrophysiologic study, to evaluate the modalities of onset and interruption of VT; endocardial mapping at multiple sites was carried out in order to define the site of origin of VT and the sequence of endocardial activation: during VT in 5/5 patients the earliest activation occurred in the left ventricle at mid septum (2 cases), in the low (1 case) and high (1 case) septal regions and in the latero-basal region (1 case); the arrhythmias always originated at the border between fibrous and viable tissue. Intraoperative mapping was carried out from 18-29 points of the epicardial surface, both in sinus rhythm (7 cases) and during VT in the 6 patients in whom the arrhythmia was inducible with electrical stimulation. During sinus rhythm fragmented electrical activity of low voltage and prolonged duration was recorded from the epicardial surface of the aneurysm in all cases; during VT the site of earliest activation was localized in the low posterior (3 cases), high lateral (2 cases) and high posterior (1 case) regions of the left ventricle. Intraoperative endocardial mapping during VT confirmed the site of origin of the arrhythmia, as determined by preoperative mapping, in the 3 cases in whom it was performed. In all cases encircling endocardial ventriculotomy around the area of earliest activation or, when the origin of VT was not precisely determined, along the border zone of the aneurysm, was associated with conventional surgical procedures (aneurysmectomy: 6 cases; incision-suture: 1 case; aorto-coronary bypass: 1 case; mitral valve replacement: 1 case). One patient died in the early post-operative course with a low-output syndrome. During a follow-up of 6-35 months, one patient died two months after surgery because of intractable heart failure; the remaining patients are alive and well, with no recurrence of VT; none of them required antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1982

Acute verapamil poisoning: successful treatment with epinephrine.

Acute intoxication with verapamil (2400 mg) induced A-V dissociation and circulatory failure in a 38-year-old woman with no previous cardiac disease. Resumption of A-V conduction was observed after administration of orciprenalin, calcium gluconate, and dopamine, with no effect on blood pressure. Epinephrine infusion finally restored satisfactory blood pressure level and allowed a favorable outcome.

Acute Disease↗
PubMed1982

Dipyridamole test in angina pectoris: diagnostic value and pathophysiological implications.

The value of the dipyridamole test (0.75 mg/kg i.v.) in the diagnosis of angina pectoris was studied in 54 patients with angina pectoris (35 with angina on effort associated or not associated with rest angina and 19 with angina only at rest) and in 12 control subjects. The test induced electrocardiographic signs of ischemia (positive test) in 74% of patients with angina on effort, while it was negative in all cases with angina only at rest and in control subjects. All anginal patients with normal coronary arteries or less than 50% stenosis had a negative test; a positive response was observed in 36, 79 and 60% of cases with one-, two-or three-vessel disease, respectively. Hemodynamic changes with a marked arteriolar vasodilatation were observed both in the negative and in the positive tests. In the positive tests no significant change of double product, blood pressure and left ventricular end-diastolic pressure occurred before ischemia appeared. The results of the study show that dipyridamole as a diagnostic test in angina pectoris has a high specificity but a lower sensitivity than exercise test. The hemodynamic and eletrocardiographic findings in the positive tests suggest that dipyridamole-induced ischemia is due to a flow maldistribution with selective subendocardial ischemia secondary to the coronary arteriolar dilatation caused by the drug.

Adult↗
PubMed1981

Treatment of vasospastic angina pectoris at rest with nitroglycerin ointment: a short-term controlled study in the coronary care unit.

The effectiveness of nitroglycerin ointment in vasospastic angina pectoris at rest was evaluated in 10 patients selected for study. The study was performed after a 24 hour control period, and a randomized single-blind crossover experimental design was followed. Two percent nitroglycerin ointment (15 mg) or placebo ointment was administered every 6 hours for a period of 48 hours each; the first treatment period was followed by a second in which each preparation was used for a 24 hour period. All patients were hospitalized in the coronary care unit; an objective evaluation was carried out using a multichannel electrocardiographic recording to assure recognition of the painless ischemic episodes. Coronary angiography showed critical stenosis of one or two vessels in 9 of the 10 patients; spasm was demonstrated in 3. Results of the ergonovine test were positive in nine of nine patients. Nitroglycerin ointment produced a significant reduction in the mean daily number of episodes during the first (12.5 +/- 3.9 versus 0.5 +/- 0.4, p less than 0.02) as well as the second treatment period (10.6 +/- 3.8 versus 0.6 +/- 0.4, p less than 0.02). These results demonstrate that nitroglycerin ointment provides effective, long-lasting protection against angina due to coronary spasm.

Adult↗