Effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina.

BACKGROUND: Literature concerning exercise-induced platelet activation in chronic stable angina is somewhat confusing. The reason lies in the type of exercise as well as in methodological problems. A powerful, recently introduced procedure to detect platelet activation is flow cytometry. Platelet response to activating factors is mediated by calcium uptake; however, calcium antagonist effect on platelet activity is still unclear. HYPOTHESIS: The study was undertaken to investigate exercise-induced platelet activation before and after treatment with amlodipine in chronic stable angina. METHODS: Twenty patients with chronic stable angina were entered into the study. Each subject underwent a symptom-limited cycloergometer stress test following a washout period of 2 weeks. Blood samples were collected before and immediately after exercise. All subjects were then randomized into two groups of 10 patients each, with Group 1 and Group 2 taking amlodipine 10 mg/day, and placebo for 4 weeks, respectively. They subsequently underwent a second exercise stress test, and blood samples were obtained before and immediately after exercise. Flow-cytometric evaluation of platelet activity was performed in order to recognize GMP-140 expression on platelet membrane. RESULTS: Strenuous exercise induced a significant increase in platelet activation in all subjects prior to therapy. No significant differences were observed in platelet activity at rest between Groups 1 and 2, whereas a significant decrease in exercise-induced platelet activation was demonstrated in Group 1 compared with Group 2. CONCLUSION: Our data provide evidence of the favorable effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina.

[Atherosclerosis and simvastatin: new questions for the new millennium]. / Aterosclerosi e simvastatina: nuovi interrogativi per il nuovo millennio.

Coronary artery disease is still associated with high morbidity and mortality in Western countries. Lipid blood levels have a tight correlation with the risk of coronary events, and the results of many trials on lipid-lowering therapy (and particularly on simvastatin) demonstrated a significant reduction in total and cardiac mortality, and in the incidence of myocardial infarction and coronary events; even the progression of coronary stenosis has been reduced by treatment with statins. Beyond cholesterol reduction, simvastatin exerts many favorable effects on endothelial function, inflammatory activity, expression of pro-thrombotic factors and oxidative stress, yielding a rational basis for its important clinical positive effects, both in primary and secondary prevention of coronary disease. Future developments, which are the subjects of many planned or ongoing clinical trials, are related to the treatment of high-risk patients, the evaluation of the efficacy of elevated simvastatin dosages and of a deep reduction in cholesterol blood levels, the interaction between simvastatin and other drugs (antioxidant compounds, vitamins, antiplatelet drugs) or interventional procedures (percutaneous transluminal coronary angioplasty). Particularly, the Heart Protection Study, the A to Z trial, and the SEARCH and SMART studies will provide important data on a wider, earlier and greater use of simvastatin, which has been demonstrated effective both in the prevention and treatment of acute coronary syndromes.

[The effects of a left bundle-branch block on ventricular repolarization dispersion]. / Effetti del blocco di branca sinistra sulla dispersione della ripolarizzazione ventricolare.

Patients with left bundle-branch block (LBBB) often present electrocardiographic abnormalities and, therefore, are excluded from studies concerning electrocardiographic evaluation of ventricular repolarization. The aim of the study was to assess whether LBBB could influence dispersion of ventricular repolarization. Surface electrocardiograms of 16 patients (9 males and 7 females, mean age 58 +/- 14 years) with episodes of intermittent LBBB were analyzed. Six patients were affected by coronary artery disease, 6 by hypertensive cardiomyopathy and 4 by dilated cardiomyopathy. Maximal QT and JT corrected intervals, QT and JT dispersion, and QT and JT dispersion corrected for heart rate, were obtained before and after LBBB. We observed a significant prolongation of maximal QT (412 +/- 29 vs 433 +/- 25 ms; p < 0.05), and of maximal corrected QT (457 +/- 37 vs 497 +/- 56 ms; p < 0.05) after LBBB. Maximal JT interval, also corrected for heart rate, did not show any significant modification after LBBB. Moreover, we did not observe any significant difference in electrocardiographic parameters of dispersion of repolarization. Our results seem to indicate that LBBB did not alter significantly dispersion of ventricular repolarization. QT dispersion is considered an important marker of risk for incidence of ventricular arrhythmias. If our results will be confirmed in larger groups of patients, analysis of QT dispersion could be extended even to patients with LBBB.

[Effects of physical activity on lipids and coagulation]. / Effetto dell'attività fisica sull'assetto lipidico e sulla coagulazione.

In order to evaluate the effects of physical activity on seric lipoproteins and coagulation parameters, an 8-week clinical trial was performed. Fifteen healthy young subjects (average age 23 years) with no history of previous agonistic physical activity, entered the study. Each subject underwent a physical programme consisting of three times a week bicycle ergometer exercise with progressive increases in work rate by using stages of 3 min duration until the 85% of the predictive heart rate was reached. Each individual was subjected to four blood drawings according to the following schedule: at the beginning of the study, after 4 weeks, after 8 weeks (at the end of the programme) and 4 weeks after the interruption of training. As far as the seric lipoproteins are concerned, the following parameters were monitored: total cholesterol, HDL-C, LDL-C, VLDL-C, triglycerides, Apo-A1, Apo-B100, NEFA and phospholipids. On the other hand the following coagulation parameters were monitored: fibrinogen PT, aPtt, coagulation factors (II-XII), red cells, leucocytes, platelets, hemoglobin and hematocrit. From the analysis of the data, the following statistically significant results were observed: HDL-C increased by 14%, LDL-C decreased by 13%, Apo-A1 increased by 6%, fibrinogen increased by 31.7%, Ptt decreased by 3.7% and leucocytes increased by 15%. Four weeks after exercise was terminated, all monitored parameters turned into the basal range. Our data seem to demonstrate a positive effect of physical exercise on seric lipoproteins in the short period. Nevertheless they provide evidence of an hypercoagulability condition demonstrated by the important fibrinogen increase and the Ptt decrease.

Incidence and risk factors associated with cardiac arrhythmias during rehabilitation after coronary artery bypass surgery.

OBJECTIVE: To evaluate the clinical relevance of cardiac arrhythmias during rehabilitation after coronary artery bypass graft (CABG) surgery. DESIGN: Survey of consecutive patients admitted to an inpatient cardiac rehabilitation center. SETTING: A rehabilitation center acting as a reference for cardiology clinics lacking this facility. The program was performed in the inpatient setting. PATIENTS: Two hundred sixty patients undergoing elective CABG surgery for angina. INTERVENTIONS: Four-week cardiac rehabilitation program. A 24-hour electrocardiographic examination was performed during the first 2 days and, subsequently, on a daily basis. MAIN OUTCOME MEASURES: Incidence and type of cardiac arrhythmias during rehabilitation; identification of factors associated with an increased risk of cardiac arrhythmias. RESULTS: Cardiac arrhythmias were recorded in 33.5% of the patients and were more frequent in patients with hypertension (47%), diabetes (42.4%), and hyperlipidemia (36.5%), compared with patients free from these diseases (15.5%) (p < .05). Arrhythmias were also recorded in patients older than 70 years (49%), compared with those younger (29.2%) (p < .01), and in patients who discontinued amiodarone (64.3%) compared with those who did not interrupt the drug (16%) (p < .005). Arrhythmias precluded rehabilitation in 5% of the patients and caused death in one patient. CONCLUSION: Surveillance for the development of cardiac arrhythmias during cardiac rehabilitation after CABG surgery may allow the early detection and treatment of arrhythmias in a substantial number of patients.