Effects of thrombolysis and atenolol or metoprolol on the signal-averaged electrocardiogram after acute myocardial infarction. Late Potentials Italian Study (LAPIS).

Late potentials (LPs) detected on the signal-averaged (SA) electrocardiogram (ECG) predict arrhythmic events after acute myocardial infarction (AMI). The effect of thrombolysis on the incidence of LPs after AMI is controversial and its impact on subsequent arrhythmic events is not known. Moreover, the effects of beta blockers on the SAECG have not been studied. Six hundred eighteen patients with AMI were studied; thrombolysis was given to 228 (37%). In comparison with patients treated conventionally, those receiving thrombolysis were significantly younger and more frequently male, had higher peak values of creatine kinase, a lower prevalence of non-Q-wave AMI, and a higher incidence of ventricular fibrillation in the acute phase, and more frequently received beta blockers. An SAECG obtained 6 to 8 days after AMI showed LPs in 24% of patients receiving and in 25% not receiving thrombolysis (p = NS). On admission, intravenous beta blockers were administered to 110 patients (18%); those receiving beta blockers were younger, had lower peak values of creatine kinase and more frequently received thrombolysis. LPs were less frequently found in patients treated than in those not treated with beta blockers (15 vs 27%; p = 0.007); however, this effect was found only in those with an ejection fraction > or = 40%. Independent predictors of LPs by multivariate analysis were an ejection fraction < 40% (p = 0.007), ventricular fibrillation in the acute phase (p = 0.02), and absence of beta-blocking therapy (p = 0.03). During a mean follow-up of 12 +/- 7 months, there were 39 cardiac deaths (6%), 13 of which were sudden (2%), and 9 sustained ventricular tachycardias.(ABSTRACT TRUNCATED AT 250 WORDS)

Sustained beneficial hemodynamic effects of low transdermal nitroglycerin doses compared with placebo in patients with congestive heart failure.

In an attempt to resolve some of the controversies concerning the dose requirements and duration of effects of transdermal nitroglycerin (NTG) in patients with heart failure (CHF), the short-term hemodynamic responses to transdermal NTG, in a 20 cm2 self-adhesive patch (10 mg/24 h), were evaluated in 10 patients with severe chronic CHF using a randomized, within-patient, double-blind, placebo-controlled cross-over trial. Serial hemodynamic measurements over 24 h revealed sustained effects that began 1 h after the application of nitroglycerin patch and fully persisted throughout the study. The peak effect occurred at 4 h with the pulmonary capillary wedge pressure decreasing from 33.7 +/- 8.4 to 21.4 +/- 9 mmHg (mean +/- SD) (p less than 0.05) and the cardiac index increasing from 2.5 +/- 0.6 to 3 +/- 0.6 l/min/m2 (p less than 0.01). Transdermal nitroglycerin also significantly reduced pulmonary arterial and right atrial pressures (from 43.5 +/- 9.5 to 31 +/- 11.4 and from 7.4 +/- 6.6 to 3.8 +/- 4.7 at peak effect, respectively) as well as pulmonary and systemic vascular resistances (from 10.7 +/- 6.6 to 6.5 +/- 3.2 and from 26.2 +/- 5.1 to 22.5 +/- 5.7, respectively). There was no change in heart rate or systemic arterial pressure. These beneficial hemodynamic responses persisted for 24 h. No rebound deterioration occurred upon withdrawal of the nitroglycerin. No significant hemodynamic changes occurred during placebo treatment period. Thus, low doses (10 mg/24 h) of transdermal nitroglycerin induce significant hemodynamic benefit that is sustained for 24 h in patients with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Late potentials, myocardial kinetics and ventricular vulnerability as markers of sudden death after myocardial infarct]. / Potenziali "tardivi", cinetica miocardica e vulnerabilità ventricolare come "markers" di morte improvvisa dopo infarto miocardico.

The 1st myocardial infarction requires the identification of patients who are at high risk of malignant ventricular arrhythmias. Our study group included 55 consecutive patients (age less than 70): all had non-invasive "signal averaging" recording and 24 hour dynamic electrocardiogram at the post-acute phase of their 1st myocardial infarction (MI) and 3 months later. Wall motion abnormalities were evaluated in each patient but two. 24 randomized patients (without documented sustained ventricular tachycardia) underwent right programmed ventricular stimulation at the 3rd month after MI and pathological repetitive responses were evaluated (Table III); they were hemodynamically stable and without persistent ischemia. Late potentials have been compared to spontaneous and induced ventricular arrhythmias, wall motion abnormalities (Table II) and two-year follow-up (Table VI), in order to identify predictive markers of sudden death or malignant arrhythmias. Ventricular late potentials were identified in 28 patients (51%) 4-8 days after MI: mean duration was equal to 75 +/- 33 msec; they did not show any relationship to the site (Table I) and to the extension of necrosis (Table II). Ventricular late potentials had no significant association with myocardial dyskinesia (Table II) while their association with complex ventricular arrhythmias, detected on Holter monitoring within 8 days after MI, and with the induction of repetitive ventricular responses (greater than or equal to 2 complexes) showed significant correlations (respectively p = 0.02; p = 0.01). In regard of the recognition of spontaneous ventricular tachycardia (greater than or equal to 3 complexes) in the follow-up, the detection of late potentials showed 75% sensibility with predictive value equal to 32% (Table V); the combination of late potentials and ventricular dyskinesia exhibited the highest specificity (88%) and predictive value (54%). By the end of follow-up there had been 6 cardiac deaths (2 sudden, 4 from left ventricular failure): late potentials longer than 75 msec were recorded in all patients who had cardiac death; in the post acute phase of MI repetitive ventricular arrhythmias were detected in only 1 of the 2 case of sudden cardiac death and in none of the patients who developed sustained ventricular tachycardia in the follow-up (Table VI). Myocardial dyskinesia was present in each patient who developed non sudden cardiac death (Table VI).(ABSTRACT TRUNCATED AT 400 WORDS)

[Prognostic value of echocardiography in acute myocardial infarct: comparison, by multivariate analysis, between mono- and bidimensional parameters]. / Validità prognostica dell'ecocardiografia nell'infarto miocardico acuto: confronto, mediante analisi multivariata, tra reperti mono e bidimensionali.

A multivariate step-wise analysis with death or heart failure as prognostic end-points was utilized in 62 patients with an acute myocardial infarction (AMI), to evaluate the age related short-term prognostic significance of selected M-Mode and two dimensional echocardiographic parameters, and to identify, among them, the best predictors of the clinical outcome. The echocardiographic examination was performed within 24 hours from the occurrence of cardiac chest pain. After a three months follow-up study, the patients were divided into groups: 9 patients who died (Group A), 53 patients who survived (Group B), subdivided into 41 asymptomatic patients (Group B1) and 12 patients with clinical signs of heart failure (Group B2). The selected parameters were: age, left ventricular end-diastolic and end-systolic diameters (LVEDD, LVESD), left atrial diameter (LAD), the electrocardiographic PR interval minus AC interval from the mitral echogram (PR-AC), the distance between the mitral E point and the septum (EPSS), total aortic excursion (TAE), and two dimensional wall motion score. From the step-wise analysis of groups A and B we classified the parameters as follows, the relative prognostic significance being highest on the left side: score greater than TAE greater than AGE greater than PR-AC greater than LVEDD (LAD, LVESD, EPSS). For groups B1 and B2 the following results were obtained: score greater than PR-AC greater than AGE greater than LVESD greater than EPSS (TAE, LVESD, LAD). In parenthesis are indicated the variables whose prognostic value did not reach any significant level. When a discriminant function was applied to the 5 most significant variables, we could identify 78% of the patients of group A, and 77% of those of the group B; of groups B1 and B2 we identified correctly 83% and 92% of the patients respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Short-term prognostic evaluation of acute myocardial infarct: comparison of 2-dimensional echocardiography, electrocardiography, and the MB-CK index]. / Valutazione prognostica a breve termine dell'infarto miocardico acuto: confronto tra l'ecocardiografia bidimensionale, l'ECG e il CPK-MB.

To compare the non-invasive methods of quantification of acute myocardial infarction (AMI) [two dimensional echocardiography (2DE), standard 12-leads ECG, and enzymatic indices as MB-CK peak activity and MB-CK time activity curve expressed by an extension index (EI-MBCK)] in relation to their prognostic value, 79 patients with a first AMI were evaluated. We have observed in a three months follow-up a total mortality of 12.6%. The infarct size, calculated echocardiographically by a segment score, was correlated with the number of pathological Q waves in the standard ECG (rho= 0.83). Peak MB-CK enzyme and EI-MBCK correlated both with the segment score, but with a lower correlation coefficient (rho= 0.67). To identify patients at different risk, discriminant analysis was used which gave the following limit values for the patients at a very high risk: 2DE score = 17; number of Q waves = 7; peak MB-CK = 176 U/L; EI-MBCK = 54 grEq/m2; for the patients at a very low risk: score = 6; number of Q waves = 2; peak MB-CK = 35; EI-MBCK = 15. To verify if the association of these different techniques could improve the predictivity, a discriminant bivariate function analysis with three variables was calculated. The resulting equation was: Z = 2.31 X 2DE score + 8.59 X number of Q waves - 0.23 X peak MB-CK. Changing peak MB-CK value with EI-MBCK did not improve the statistical significativity. The results have confirmed that the integration of all the three variables improved the prognostic predictivity. According to the risk Z obtained, the patients were allocated into classes of different risk: values of Z greater than 57 or less than 18 could identify patients respectively at a very high or at a very low risk. For values between 37 and 42 the prognosis remains uncertain. Among the three variables, 2DE and ECG showed an equivalent prognostic accuracy, whereas enzyme indices had a lower prognostic influence, especially in the presence of large infarcts. Thus, 2DE, ECG and enzyme indices can identify patients at increased risk; the individual method seems to be inadequate; to obtain valid predictive informations it is necessary to integrate all the three non invasive techniques.