Continuous electrocardiographic monitoring for more than one hour does not improve the prognostic value of ventricular arrhythmias in survivors of first acute myocardial infarction.

This study was designed to compare the prognostic value of predischarge ambulatory electrocardiographic monitoring for 1, 6 and 24 hours in 188 patients surviving a first acute myocardial infarction. Ventricular premature complexes (VPCs) were considered as a mean hourly rate or classified using Lown and Moss grading systems. During the 1-year follow-up 20 cardiac deaths occurred. For all 3 monitoring times, a higher number of VPCs/hour and a higher Moss grade were associated with mortality, whereas a Lown grading system gave prognostic information only for the first hour of recording. Monitoring time did not influence specificity or sensitivity in predicting mortality; > or = 3 VPCs/hour showed a higher sensitivity than > or = 10 VPCs/hour (p < 0.05) with a comparable specificity. After 1-hour data entered the model, neither the 6- or the 24-hour data entry improved the overall likelihood ratio statistic, regardless of what VPC grading system was used. These results demonstrate that continuous electrocardiographic recordings of > 1 hour are unnecessary when they are to be used for detecting ventricular arrhythmia as a predictor of mortality in patients surviving a first acute myocardial infarction.

Effects of converting enzyme inhibition on baroreflex sensitivity in patients with myocardial infarction.

BACKGROUND: Baroreflex sensitivity provides useful prognostic information in patients after acute myocardial infarction. However, no data are available about the effects of converting enzyme inhibition on this variable. OBJECTIVES: The aim of the study was to evaluate the effects of angiotensin-converting enzyme inhibition on baroreflex sensitivity in patients after uncomplicated myocardial infarction. METHODS: Twenty-five patients after uncomplicated myocardial infarction underwent baroreflex sensitivity evaluation 72 to 96 h after symptom onset and after 4 days of captopril therapy. Twenty additional patients with the same characteristics were evaluated at the same time intervals before and after placebo administration to identify spontaneous baroreflex sensitivity variations. Baroreflex sensitivity was assessed by calculating the regression line relating phenylephrine-induced increases in systolic blood pressure to the attendant changes in the RR interval. RESULTS: The mean baroreflex sensitivity value increased after captopril administration from 6.5 +/- 4.2 to 11.8 +/- 6.1 ms/mm Hg (p less than 0.01) and in individual analyses increased by greater than 2 ms/mm Hg in 68% of patients. Mean plasma renin activity increased after captopril from 3.7 +/- 2.4 to 8.5 +/- 4.9 ng/ml per h (p less than 0.005). No difference was detectable in baroreflex sensitivity and plasma renin activity values according to the site of necrosis. In the control group, baroreflex sensitivity and plasma renin activity remained unchanged between the two studies. CONCLUSIONS: This study demonstrates that in patients with uncomplicated myocardial infarction, captopril significantly improves the chronotropic response to baroreceptor stimulation.

Effects of captopril treatment on left ventricular remodeling and function after anterior myocardial infarction: comparison with digitalis.

The effects of captopril and digoxin treatment on left ventricular remodeling and function after anterior myocardial infarction were evaluated in a randomized unblinded trial. Fifty-two patients with a first transmural anterior myocardial infarction and a radionuclide left ventricular ejection fraction less than 40% were randomly assigned to treatment with captopril (Group A) or digoxin (Group B). The two groups had similar baseline hemodynamic, coronary angiographic, echocardiographic and radionuclide angiographic variables. Among the 40 patients (20 in each group) who were followed up for 1 year, echocardiographic end-diastolic and end-systolic volumes were unmodified in Group A and global wall motion index was improved (p less than 0.01); in Group B, end-diastolic and end-systolic volumes increased (p less than 0.001 for both) and global wall motion index was unchanged. Rest radionuclide ejection fraction increased significantly in both groups (p less than 0.001, Group A; p less than 0.005, Group B). A comparison of the changes in the considered variables between the two groups after 1 year of treatment showed a difference in end-diastolic (p less than 0.005) end-systolic volumes (p less than 0.001) and global wall motion index (p less than 0.005) without differences in radionuclide ejection fraction, which improved to a similar degree in both groups. The results of this study suggest that captopril therapy, started 7 to 10 days after symptom onset in patients with anterior myocardial infarction and an ejection fraction less than 40%, improves both left ventricular remodeling and function and prevents left ventricular enlargement and in these patients performs better than digitalis.

[Influence of age on the short- and medium-term prognosis in patients with acute myocardial infarct]. / Influenza dell'età sulla prognosi a breve e medio termine nei pazienti con infarto acuto del miocardio.

Elderly patients with acute myocardial infarction (AMI) have a higher subsequent mortality than younger ones, yet the reasons for this adverse prognosis are poorly understood. We compared the clinical course and the prognosis of 163 patients aged 40 to 69 years with 112 patients older than 70 years. During hospitalization period 15.9% of younger and 37.5% of older patients died; at 1 year follow-up the cardiac mortality rate was 8.7% in younger and 12.9% in older patients. In elderly patients a greater prevalence of female gender, diabetes mellitus, anterior myocardial infarction, atrial fibrillation and a greater incidence of heart failure and shock were observed. Multivariate stepwise analysis identified shock and heart rate greater than or equal to 90 bpm at the time of admission as the most important prognostic variables for in-hospital mortality in both groups; heart failure (Killip class II and III) was significant in younger patients, while non Q wave myocardial infarction correlated with a better prognosis in elderly. In elderly patients who survived AMI, predischarge Holter monitoring showed higher frequency and complexity of ventricular arrhythmias, and radionuclide angiography lower left ventricular ejection fraction (E.F.) values. In these patients no difference was found in E.F. values despite myocardial infarction sites. At 1 year follow-up E.F. less than 40% and ventricular arrhythmias (3-4 Moss grading system) were significantly related to prognosis in younger patients, while E.F. less than 40% and clinical signs of heart failure in elderly. Therefore, low E.F. and heart failure account for a worse prognosis in elderly patients, while ventricular arrhythmias in younger ones. The results of this study support aggressive management even in elderly patients following AMI to preserve left ventricular function. In elderly patients a large use of antiarrhythmic drugs is not recommended because of low prognostic value of ventricular arrhythmias.

Beneficial effect of a new prostacyclin derivative on the walking capacity in patients with peripheral arterial insufficiency.

The efficacy, tolerance and safety of iloprost, a stable analogue of carbaprostacyclin, were evaluated in 7 patients with peripheral arterial insufficiency at stage II of Fontaine's classification. After washout, placebo was infused intravenously for seven days, then iloprost was given by a six-hour intravenous infusion of 1 ng/kg/min over the next seven days. At the end of each period, the initial (ICD) and the absolute (ACD) claudication distance were measured by treadmill. The ankle/arm systolic blood pressure ratio (WI) was also assessed, at rest and ten minutes after exercise. As compared with placebo, ICD increased from 98 +/- 60 to 137 +/- 91 meters (p less than 0.05) and ACD from 151 +/- 76 to 210 +/- 95 meters (p less than 0.05). Similarly, WI rose from 0.44 +/- 0.14 to 0.52 +/- 0.18 (p less than 0.05) at rest and from 0.40 +/- 0.13 to 0.48 +/- 0.20 (p less than 0.05) ten minutes after treadmill exercise. Owing to the spontaneous fluctuation in walking distance experienced by such patients, an increase in ACD greater than or equal to 50% was considered as clinically relevant. In 3 patients, who experienced such an improvement, iloprost continued to be infused at the same dosage as before, for an additional seven days. In the remaining 4 patients (nonresponders), the dose was increased to 2 ng/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of L-carnitine on the reactive hyperemia in patients affected by peripheral vascular disease: a double-blind, crossover study.

A double-blind, crossover study was designed to evaluate the effect of L-carnitine on the reactive hyperemia in patients with peripheral vascular disease. After drug washout, 18 patients were randomly assigned to receive placebo or L-carnitine, 3 g IV as a bolus, followed by continuous intravenous infusion of 2 mg/kg/min for thirty minutes. Blood flow in the affected limb was measured by impedance plethysmography, under resting conditions and every two minutes for ten minutes after a five-minute ischemia induced in the affected limb. As compared with placebo, L-carnitine did not modify blood flow at rest. On the contrary, the hyperemic response with carnitine was higher than that observed with placebo. A significant increase in blood flow was found two, four, and six minutes after the release of ischemia with placebo, whereas the blood perfusion to the affected limb rose significantly at all times of recording after carnitine administration. Moreover, the values of the blood flow at two and ten minutes with carnitine were significantly higher than those recorded after placebo at the same times of recording. After the release of ischemia, the mean maximum value of blood flow observed after carnitine was 3.1 +/- 1.4 mL/min/100 mL, a value significantly higher than that recorded after placebo, which was 2.7 +/- 1.3 mL/min/100 mL (p less than 0.05). In conclusion, this study demonstrates that L-carnitine, although not affecting blood flow and ankle/arm systolic blood pressure ratio under resting conditions, improves the functional circulatory reserve in patients with peripheral vascular disease.

Increases in walking distance in patients with peripheral vascular disease treated with L-carnitine: a double-blind, cross-over study.

A double-blind, cross-over study was designed to evaluate the effects of L-carnitine in patients with peripheral vascular disease. After drug washout, 20 patients were randomly assigned to receive placebo or L-carnitine (2 g bid, orally) for a period of 3 weeks and were then crossed over to the other treatment for an additional 3 weeks. The effect on walking distance at the end of each treatment period was measured by treadmill test. Absolute walking distance rose from 174 +/- 63 m with placebo to 306 +/- 122 m (p less than .01) with carnitine. Biopsy of the ischemic muscle, carried out before and after 15 days of L-carnitine administration in four additional patients, showed that treatment significantly increased total carnitine levels. An additional goal of this study was to ascertain the effects of L-carnitine on the metabolic changes induced by exercise in the affected limb. In six patients under control conditions, arterial and popliteal venous lactate and pyruvate concentrations were determined at rest, when the maximal walking distance was reached, and 5 min after the walking test. Twenty-four hours later, L-carnitine was administered intravenously (3 g as a bolus followed by an infusion of 2 mg/kg/min for 30 min) and metabolic assessments were repeated. Five minutes after the walking test, popliteal venous lactate concentration increased by 107 +/- 16% before treatment and by only 54 +/- 32% (p less than .01) after carnitine. Furthermore, carnitine induced a more rapid recovery to the resting value of the lactate/pyruvate ratio.(ABSTRACT TRUNCATED AT 250 WORDS)