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M Previtali

Publications and source records attributed to M Previtali.

At least 19 recordsLinked to original sources
PubMed1992

Platelet function after in vivo and in vitro treatment with thrombolytic agents.

Whereas in vitro studies showed that plasmin may induce both inhibition and activation of platelets, in vivo and ex vivo investigations suggested that thrombolytic agents are responsible for platelet stimulation. To gain further information on this topic, ex vivo platelet function was studied in 24 subjects with acute myocardial infarction treated with streptokinase or recombinant tissue-type plasminogen activator (rt-PA). Ten patients with acute myocardial infarction who did not receive thrombolytic treatment were also investigated. The data shows that at the end of thrombolytic infusion, the maximal extent of platelet aggregation and adenosine triphosphate release was reduced in treated patients compared with that in untreated ones. In subjects treated with streptokinase, the defect in platelet aggregation derived from both cellular and plasmatic defects. Plasmatic beta-thromboglobulin concentration was significantly reduced after streptokinase, but unchanged after rt-PA. Three days after thrombolytic treatment, platelet aggregation of patients receiving streptokinase or rt-PA was not significantly different from that of untreated subjects. A similar defect in platelet function was obtained in vitro, incubating normal platelet-rich plasma with pharmacologic concentrations of streptokinase. Again, platelet function defect derived from both cellular and plasmatic damages. It cannot be excluded that platelet activation occurs in patients with acute myocardial infarction during the very early phases of thrombolytic treatment. However, it is suggested that a transient defect in platelet function follows both streptokinase and rt-PA infusion.

Adenosine Triphosphate↗
PubMed1992

Dobutamine-induced ST segment elevation in a patient with angina at rest and critical coronary lesions.

A case of dobutamine-induced ST-segment elevation in a patient with angina at rest and severe two-vessel disease is described. Coronary angiography performed during the ischaemic episode showed patency of coronary arteries; ST-segment elevation and chest pain regressed after propranolol administration. This case suggests that in the presence of severe coronary lesions dobutamine may produce transmural myocardial ischaemia by increasing myocardial oxygen demand and inducing myocardial blood flow maldistribution.

Angina Pectoris↗
PubMed1992

[Prognostic value of the dipyridamole-echocardiography test immediately after a non-complicated myocardial infarct: a large scale multicenter study. Echo Persantine Italian Cooperative Study].

BACKGROUND: Any new diagnostic test should follow a pathway similar to that of a new drug, from initial studies in highly selected populations under strictly controlled conditions, up to large scale multicenter trials more likely to represent the true performance of the test in the clinical arena. AIM OF THE STUDY: To evaluate the capability of prognostic stratification of high dose (up to 0.84 mg/kg over 10') dipyridamole-echocardiography test (DET) early after an acute myocardial infarction in a "phase IV" study, based upon 11 different echocardiographic laboratories, all with established experience in stress echo and fulfilling quality control requirements for stress echo readings. STUDY POPULATION: Nine-hundred twenty five patients were evaluated after a mean of 10 days from an acute myocardial infarction and followed up for a mean of 14 months. RESULTS: During DET, one major adverse reaction occurred, consisting of a prolonged ischemia resistant to aminophylline and nitrates, and progressing to small uncomplicated reinfarction. In 11 patients the lower dipyridamole dose (0.56 mg/kg over 4') gave limiting side effects. Patients were followed up for 14 +/- 9.9 months (range = 1.53). During the follow-up, there were 34 deaths and 37 non-fatal myocardial infarctions; 104 patients developed class III or IV angina, and 149 had coronary revascularization procedures (bypass or angioplasty). Considering all spontaneous events (angina, reinfarction and death), the most important univariate predictor was the result of DET (chi-square = 45.8). With a Cox analysis, echocardiographic positivity, age and sex were found to have an independent and additive value. Considering survival (and therefore death as the only event) age was the most meaningful parameter, followed by the Wall Motion Score Index during dipyridamole (chi-square = 12.1); among other parameters, the resting Wall Motion Score Index was a significant predictor of death. By Cox analysis, age (relative risk estimate = 1.02) and Wall Motion Score Index during dipyridamole (relative risk estimate = 14) showed an independent and additional prognostic value. In particular, considering death only, the event rate was of 2% in patients with negative DET, 4% in patients with high dose positive DET and 7% in patients with low dose positive DET. CONCLUSIONS: Dipyridamole echocardiography is feasible and safe early after uncomplicated myocardial infarction and allows an effective risk stratification on the basis of the presence, severity, extent and timing of the induced dyssynergy. In particular, the risk of death doubles in patients with high dose positivity and almost quadruples in patients with low dose positivity.

Adult↗
PubMed1992

[Hemodynamic effects of enalapril in patients with non-complicated acute myocardial infarct].

To evaluate the hemodynamic effects of the first oral administration of enalapril maleate, a long-acting ACE-inhibitor, in the early phase of an acute uncomplicated myocardial infarction, we studied 15 patients, in Killip class I or II, within 72 hours from the onset of symptoms. Hemodynamic measurements were obtained by a triple lumen 7 F Swan-Ganz catheter, inserted into the pulmonary artery, under control conditions and 2, 4, 6, 8 and 12 hours after 10 mg (15 patients) and 20 mg (11 patients) of the drug. Ten milligrams of enalapril reduced systolic and mean arterial blood pressure (from 118 +/- 17 to 111 +/- 18 mmHg, p < .05, and from 92 +/- 12 to 83 +/- 12 mmHg, p < .01, respectively), with a maximum effect after 4 hours from administration. Heart rate and vascular resistances showed an insignificant trend toward reduction, and no changes were observed in left ventricular systolic work index, right and left ventricular filling pressures or cardiac index. Hemodynamic changes induced by 20 mg of the drug, in a smaller group of patients, had a similar trend, which did not reach a statistical significance. In conclusion, in patients with acute uncomplicated myocardial infarction, a single oral dose of enalapril maleate is safe and well tolerated, does not induce severe hypotension, and produces potentially beneficial changes in hemodynamics.

Administration, Oral↗
PubMed1992

[Comparison of results of echo-dobutamine and ECG-dobutamine tests in the diagnosis of coronary disease].

The aim of the study was to compare the results of 2D-Echocardiographic (ECHO) vs 12-lead Electrocardiographic (ECG) monitoring during Dobutamine (DOB) infusion performed as a stress test in patients referred for the evaluation of chest pain of suspected ischemic origin. Fourty-seven consecutive patients, 40 m and 7 f, mean age 52 +/- 9 years, were studied after interruption of any antianginal therapy. DOB was infused in 5-minute stages with incremental doses of 5 mcg/kg/min up to a maximal dose of 40 mcg/kg/min. 2D-ECHO monitoring could not be performed in 3 out of 47 patients because of a poor acoustic window. Thus, the overall feasibility was 94% for 2D-ECHO DOB test vs 100% for ECG DOB test (p = ns). The ECG and 2D-ECHO findings were compared in the remaining 44 patients. Criteria for positivity were: transient regional dyssynergy absent or of lesser degree in the baseline examination for 2D-ECHO; ST-segment shift > 0.1 mV from baseline for ECG. The test was stopped when a regional wall motion abnormality developed even in the absence of significant ECG changes. Angiographically assessed coronary artery disease (CAD) was considered significant when a > 50% reduction of the luminal diameter in at least 1 major coronary vessel occurred. There were 10/44 patients with no significant CAD and 34/44 patients with CAD; 16 had single, 18 double or triple and/or left main vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Dobutamine versus dipyridamole echocardiography in coronary artery disease.

Dobutamine and dipyridamole echocardiography are gaining popularity as exercise-independent stress tests for the diagnosis of coronary artery disease. To compare the feasibility, sensitivity, and specificity of dobutamine echocardiography to dipyridamole echocardiography, we conducted both tests, on different days and in random order, on 35 patients with chest pain and suspected coronary artery disease. Dobutamine was administered in scalar doses up to 40 micrograms/kg per minute and dipyridamole up to 0.84 mg/kg for 10 minutes. Dobutamine echocardiography testing was positive in eight of 16 (50%) patients with single-vessel disease and in 11 of 12 (92%) patients with multivessel disease, resulting in an overall sensitivity of 68% for the presence of coronary artery disease. Dipyridamole echocardiography testing showed the same sensitivity as dobutamine in patients with multivessel disease but a lower sensitivity (31%) in single-vessel disease, resulting in an overall sensitivity of 57%. The specificity of both tests was 100%. An ST segment shift of more than 1 mm compared with baseline was documented in 74% of the positive dobutamine echocardiography tests and in 81% of the positive dipyridamole echocardiography tests. No major complications occurred during both tests. Ventricular arrhythmias occurred in 11 patients with dobutamine and in none with dipyridamole (31% versus 0%, p less than 0.001). Thus, in our selected population dobutamine echocardiography testing demonstrated a similar overall sensitivity and specificity for the diagnosis of coronary artery disease compared with dipyridamole, with a slightly better sensitivity for single-vessel disease but a greater arrhythmogenic potential.

Angiography↗
PubMed1990

[Comparison of two-dimensional echocardiography and hemodynamic monitoring in acute myocardial infarct].

The aim of this study was to assess if in patients with acute myocardial infarction, two-dimensional echocardiographic asynergy index is correlated to hemodynamic parameters. Furthermore, we compared how reliable the 2 methods are to identify patients at a high risk of developing early left ventricular failure. Fifty-four consecutive patients (43 males, 11 females, mean age: 61 +/- 13 years with acute myocardial infarction were studied using hemodynamic monitoring and 2D-echocardiography within 24 hours from admission. The 2D-echo asynergy index, calculated on a 14-segment left ventricular model, was significantly correlated to heart rate (r = 0.49, p less than 0.001), pulmonary capillary wedge pressure (r = 0.47, p less than 0.001), systemic vascular resistance (r = 0.47, p less than 0.001), cardiac index (r = -0.46, p less than 0.001) and left ventricular stroke work index (r = -0.63, p less than 0.001). Both the asynergy index and the hemodynamic parameters were correlated to Killip clinical classification. In the sub-group of 46 patients initially classified as belonging to Killip class I or II, the patients who later developed left ventricular failure or those in whom it worsened showed a higher asynergy index and a greater impairment of left ventricular function when compared to the patients with an uncomplicated clinical course. The sensitivity of an asynergy index greater than or equal to 1 in predicting early cardiac failure was 75%, the specificity was 64%, the positive predictive value was 43% and the negative predictive value was 88%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Expansion of the infarct area in anterior myocardial infarct: a short-term clinical and echocardiographic study].

Forty-five patients with a first anterior myocardial infarction were studied by serial two-dimensional echocardiographic examinations to evaluate the incidence, short-term evolution and clinical significance of infarct expansion. Infarct expansion was found in 26 patients (58%); in 22 cases it was detected at the first examination 24 hours after the onset of symptoms, while in the other 4 it developed later. In 20 (77%) patients expansion involved only the septal and apical regions, while in 6 (23%) it extended to the antero-lateral wall. Two out of 22 patients with early expansion died of cardiogenic shock; expansion of the infarcted area progressively increased in 10 of the remaining 20 patients and remained stable in the other 10. Compared to the patients without expansion those with expansion had a higher CK peak level, a greater number of pathological Q waves and a greater echocardiographic asynergy score; moreover, in-hospital mortality and the incidence of left ventricular failure were higher in the group with expansion (8% vs 0% and 54% vs 10% respectively). Thus our results show that in patients with anterior infarction, expansion is a frequent event which usually develops early and may have a progressive course; infarct expansion, especially when it is large and progressive, is associated with a high incidence of early left ventricular failure and has a poor prognostic significance.

Adult↗
PubMed1989

Hyperventilation and ergonovine tests in Prinzmetal's variant angina pectoris in men.

Hyperventilation and ergonovine tests were carried out in a group of 30 patients with variant angina to assess the sensitivity of the 2 tests and to correlate the response with spontaneous disease activity. Hyperventilation produced a positive response in 83% (25 of 30) and ergonovine in 93% (28 of 30) of the patients. After hyperventilation 22 of 25 showed ST-segment elevation, 2 ST depression and 1 T-wave pseudonormalization; after ergonovine ST-segment elevation developed in 23 patients, ST depression in 4 and T-wave pseudonormalization in 1. In all cases the electrocardiographic changes occurred in the same leads as during the spontaneous attacks. The incidence of chest pain and ventricular arrhythmias was similar during both tests; spontaneous remission of ischemia, however, was more frequent (48 vs 14%) after hyperventilation than after ergonovine. Acute ischemia developed at a mean of 218 +/- 112 seconds after the end of hyperventilation in 19 of 25 positive tests; at that time double product was not significantly different from basal values. The sensitivity of hyperventilation was similar (95 vs 100%) to ergonovine in the patients with greater than or equal to 1 daily attack, while in those with less than 1 daily attack the sensitivity of hyperventilation decreased to 55% compared to 77% with ergonovine. Thus, in variant angina the sensitivity of both tests correlates with disease activity. Hyperventilation is a safe provocative test with a sensitivity similar to ergonovine in patients with active disease; however, in patients with sporadic attacks hyperventilation has a lower sensitivity than ergonovine and therefore a limited diagnostic value.

Adult↗
PubMed1989

Time-related decrease in sensitivity to ergonovine in patients with variant angina.

Eighteen patients with variant angina, a positive ergonovine test, and a favorable response to calcium antagonists were studied by serial ergonovine tests and Holter monitoring to assess the long-term changes in response to ergonovine and the relationship with the spontaneous activity of the disease. The number of patients with a positive test decreased from 18 of 18 in the acute phase to 12 of 18 (66%) at 3 months, 10 of 17 (59%) at 6 months, and five of 17 (29%) at 12 months. The mean dose level of ergonovine associated with a positive response and the percentage of positive tests with ST segment depression increased progressively during follow-up. The results of the ergonovine test were well correlated with the spontaneous activity of the disease in 94%, 83%, 76%, and 71% of the patients at initial observation and at 3, 6 and 12 months, respectively. Thus in patients with variant angina and a favorable response to calcium antagonists, a time-related decrease in sensitivity to ergonovine develops during follow-up. In most patients the response to ergonovine is well correlated with the spontaneous activity of the disease; thus the ergonovine test may be a useful tool in the assessment of the natural evolution of vasospastic angina.

Adult↗
PubMed1989

Hyperventilation and ergonovine tests in Prinzmetal's variant angina: comparative sensitivity and relation with the activity of the disease.

Hyperventilation (HV) and ergonovine (E) tests were carried out in a group of 32 patients with variant angina to compare their sensitivity and to correlate the results with the activity of the disease. The HV test was positive in 84% of the patients and E in 94% of them; the percentage of positive responses to HV was similar to that to E (96% vs 100%) in the patients with daily attacks, while it was lower (55% vs 77%) in those with sporadic attacks. All 27 patients with a positive HV also had a positive response to E, while of the five patients with a negative HV, two also had a negative response to E and the other three had a positive E at a higher dose than that of the patients with daily attacks. The incidence of chest pain and of ST-segment elevation or depression or T-wave positivization was similar during the two tests; however, spontaneous remission of ischaemia was more frequent after HV than after E and ventricular arrhythmias less frequent during the HV test. At the onset of myocardial ischaemia pH was significantly higher compared with basal values (7.51 +/- 0.07 vs 7.38 +/- 0.05, P less than 0.001), while double product was not significantly different compared with basal (10.0 +/- 2.4 vs 9.2 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris, Variant↗
PubMed1988

Comparison of the effectiveness of dihydroquinidine and quinidine on ventricular ectopy after acute and chronic administration.

The aim of this study was to compare the pharmacokinetics and antiarrhythmic activity of dihydroquinidine and quinidine in 14 patients (11 men, 3 women, aged 28 to 67 years) with heart disease and chronic, stable, high-frequency premature ventricular beats (PVB) (greater than 100/hr). A randomized, double-blind, crossover, placebo-controlled protocol was utilized. During Holter monitoring the patients were given either dihydroquinidine or quinidine as the gluconates in an oral solution (600 mg); blood samples were taken 0.5, 1, 1.5, 2, 4, 6, 8, and 12 hours later. The patients were then assigned to three successive treatment periods of 7 days each: dihydroquinidine HCl (900 mg/day), quinidine polygalacturonate (1,650 mg/day), or placebo. At the end of each period 24-hour Holter monitoring was carried out and a blood sample was taken for determination of drug concentration. By comparing the area under the curves dihydroquinidine was 59% as available as quinidine; rates of absorption and elimination were similar. Mean peak blood levels of dihydroquinidine and quinidine were 1.06 +/- 0.34 and 2.15 +/- 0.96 micrograms/ml, respectively. After dihydroquinidine, eight patients had a positive response (greater than 50% reduction in PVB frequency), while seven patients responded to quinidine. During maintenance treatment both dihydroquinidine (233 +/- 330) and quinidine (234 +/- 311) reduced the mean PVB frequency per hour compared to placebo (690 +/- 569). Nine patients (64%) on dihydroquinidine and eight (57%) on quinidine had greater than 70% decrease in mean PVB frequency per hour. Steady-state peak plasma concentrations of dihydroquinidine and quinidine were 1.10 +/- 0.41 and 2.24 +/- 1.13 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Spontaneous remission of variant angina documented by Holter monitoring and ergonovine testing in patients treated with calcium antagonists.

Twenty-four patients with Prinzmetal's variant angina showing a favorable initial response to calcium antagonist treatment were studied to assess the evolution of the disease and the frequency and time course of spontaneous remission. At 3, 6 and 12 months from the acute phase, patients underwent in-hospital control studies, with 48-hour Holter monitoring and ergonovine testing carried out during treatment and after its interruption. During calcium antagonist therapy complete protection from spontaneous attacks was documented in 22 of 24 patients at 3 months, in 19 of 21 at 6 months and in all 21 at 12 months; ergonovine test results were negative in 16 of 23 patients at 3 months, in 16 of 20 at 6 months and in all 20 studied at 12 months. After stopping treatment spontaneous attacks did not reappear in 7 of 24 patients (29%), 14 of 21 (66%) and 16 of 21 (76%) at 3, 6 and 12 months respectively, while the ergonovine test response remained negative in 6 of 21 (28%), 7 of 18 (39%) and 13 of 20 (65%) of the patients controlled at 3, 6 and 12 months. Thus, complete remission of angina documented by both Holter recording and ergonovine testing occurred in 5 of 24 patients (21%) at 3 months, in 7 of 21 (33%) at 6 months and in 12 of 21 (57%) at 12 months. Patients with remission of angina had a shorter duration of symptoms and more often showed normal or not critically diseased coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1987

Electrophysiologic and clinical effects of intravenous and oral encainide in patients with Wolff-Parkinson-White syndrome and paroxysmal atrial fibrillation.

The electrophysiologic effects of encainide were studied in 10 patients with Wolff-Parkinson-White syndrome after intravenous (1 mg kg-1 in 60 minutes) and oral administration of two dose regimens (75 and 150 mg daily). Under control conditions atrial fibrillation (AF) with a rapid ventricular response was induced in all patients and atrioventricular reciprocating tachycardia (AVRT) in 9 patients. After intravenous encainide AF was no longer induced in 3/9 patients; in 3 of the remaining the accessory pathway (AP) was totally blocked and in the others the shortest RR interval increased from 213 +/- 6 to 297 +/- 91 ms and the mean RR interval from 293 +/- 39 to 362 +/- 79 ms. The lower dose of oral encainide prolonged the shortest RR interval from 206 +/- 24 to 273 +/- 64 ms and the mean RR interval from 280 +/- 48 to 368 +/- 52 ms in 6 patients; in 2 cases no preexcited beats were recorded and in 1 AF was not inducible. After the higher dose of oral encainide AF was still inducible in 7/8 cases; in 3 the AP was blocked and in the others the shortest and mean RR intervals increased from 202 +/- 30 to 280 +/- 24 ms and from 276 +/- 59 to 436 +/- 80 ms, respectively. After intravenous encainide antegrade conduction over the AP was blocked in 4/9 patients and the antegrade effective refractory period (ERP) was prolonged in another 4. Oral encainide blocked AP conduction in 4 cases and prolonged ERP considerably in the others.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗