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Biomedical subjects

M Chiariello

Publications and source records attributed to M Chiariello.

At least 271 records · Page 15Linked to original sources
PubMed1986

Relation between QT and QS2 intervals during exercise and recovery. Response in patient with coronary artery disease and age-matched control subjects.

We investigated the relationship between QT interval and QS2 (electromechanical systole) during exercise and recovery in patients with coronary artery disease (CAD) and exercise-induced myocardial ischemia (n = 12), and in age-matched controls (n = 20). Upright bicycle exercise was performed (50 watts/min + 20 watts/min every 2 min), recording electrocardiographic lead 2 (100 mm/sec) for QT and QS2 measurement at rest, at each step of uninterrupted exercise and every 60 sec during a 3-min recovery period. Resting data showed a QT less than QS2 finding in both groups; during exercise, QT and QS2 decreased. The values of QT and QS2, collected at each step of exercise and plotted against heart rate (HR) separately for both groups, showed a significant correlation coefficient. Comparing the regression lines of HR-QT and HR-QS2 separately for both groups, we found that both intervals decreased in parallel and the mean QT remained shorter than QS2 in both groups during exercise. The QT/QS2 ratio remained unchanged significantly during exercise and recovery in CAD. In control subjects, the ratio remained unchanged during exercise and the first min of recovery, while a significant change was detected in late (2,3 min) recovery from an adrenergic-induced effect. The mean exercise-induced response of QT-QS2 relationship includes a QT less than QS2 pattern in both groups. In CAD patients, an abnormal pattern was found in two patients during recovery by a relative prolongation of QT, suggesting the possibility of a risk factor for dangerous arrhythmias or sudden death.

Blood Pressure↗
PubMed1986

Noninvasive techniques in clinical pharmacology. Time intervals in assessment of vasodilators in coronary artery disease.

We enrolled 15 male volunteers with angiographic evidence of coronary artery disease (CAD) to investigate the effects of sublingual administration, on different days, at random, of placebo and three drugs with different action such as isosorbide dinitrate, nifedipine and molsidomine. We recorded simultaneously electrocardiogram, phonocardiogram and carotid pulse at paper speed of 100 mm/s; blood pressure was measured by auscultatory method. We calculated the systolic time intervals (STI) being noninvasive indices of left ventricular function and the ratio of diastolic time to heart rate (%D), well related to coronary blood flow in patients with severe obstructive lesions. Placebo decreased heart rate (HR) without effects on STI or %D. Isosorbide dinitrate induced a prolonged pre-ejection period (PEP) (by decreasing preload), tachycardia and a significantly decreased %D, suggesting a fall in coronary blood flow time. Nifedipine decreased diastolic blood pressure and values of PEP (by decreasing afterload) without effects on %D. Finally, molsidomine prolonged PEP (by decreasing preload) without reflex induced tachycardia and changes of %D. In conclusion, mechanocardiography can be useful in noninvasive assessment of vasodilators in CAD patients.

Blood Pressure↗
PubMed1986

Iatrogenic occlusion of the left anterior descending coronary artery. A case report.

A 27-year-old man with mixed aortic stenosis and regurgitation formerly stabbed in the left anterior part of the chest was admitted to our department with dyspnea. Coronary arteriography, performed during cardiac catheterization, showed total occlusion of the left anterior descending coronary artery. The Authors point out the iatrogenic cause of the coronary occlusion. It was due to ligation of the artery when suturing the ventricular wound.

Adult↗
PubMed1986

Long-term management of exercise-induced myocardial ischemia. Diltiazem versus propranolol, a double-blind, crossover study.

The authors performed a long-term, double-blind, crossover study on the effect of two drugs (propranolol, 40 mg t.i.d. or diltiazem, 60 mg t.i.d., each administered for 2 months) on their exercise tolerance in 13 patients with stable angina (mean age 52 +/- 7 years, 9 males and 4 females), after exertion and documented significant (greater than or equal to 70%) obstructive coronary lesions at angiography. Only propranolol, by decreasing heart rate and rate-pressure product, improved maximal sustained work load and duration of exercise (measured by a bicycle ergometer) versus the placebo (p less than 0.05). In both cases, however, they did not find any significant difference between propranolol and diltiazem. ST segment depression was decreased by both drugs (-1.73 +/- 0.95, baseline, vs -0.94 +/- 1.01, propranolol, and -0.95 +/- 0.76, diltiazem, p less than 0.5, for both). Long-term management of stable angina on effort therefore, can be usefully performed using propranolol or diltiazem.

Adult↗
PubMed1985

[Ventricular tachycardia].

Various electrocardiographic forms of ventricular tachycardia are described. After a discussion of the different pathogenetic mechanisms about this arrhythmia, the various types of pharmacological and electrical treatment are examined.

Amiodarone↗
PubMed1985

Relation between heart rate and QT interval in exercise-induced myocardial ischemia.

The relation between heart rate and QT interval during dynamic upright exercise on a bicycle ergometer was investigated in control subjects (n = 18) and in patients with coronary artery disease (CAD), stable angina on effort, and angiographically documented significant coronary stenoses (n = 23). Both groups had a significant negative linear relation between heart rate and QT, with a higher correlation coefficient in control subjects (r = -0.78) than in patients with CAD (r = -0.64). This response may be a result of the nonhomogeneous response to ischemia in patients with CAD, particularly with regard to the different impact of exercise-induced ischemia. When the 2 regression lines were compared, a flatter slope was found in the CAD group (p less than 0.001) as a consequence of a faster decrease in the QT-increasing rate in control subjects. It is suggested that in control subjects exercise-induced increase in adrenergic tone causes a rapid and relevant decrease in QT-interval duration. In the CAD group, exercise-induced ischemia relatively prolonged the QT interval; this may have been the result of an impairment of myocardium in response to catecholamines release during exercise or the consequence of a direct effect of exercise-induced ischemia prolonging the duration of myocardial tension.

Adult↗
PubMed1985

24-hour blood pressure recording in patients with orthostatic hypotension.

Continuous intra-arterial blood pressure measurement and electrocardiograms were obtained in two ambulatory patients with orthostatic hypotension due to autonomic dysfunction. Systolic and diastolic arterial pressure presented marked variations which took place mainly during the day and were related to several physical activities; however, marked falls in blood pressure were also observed during sleep and at the moment of arousal. A peak incidence of hypotensive events was found in the afternoon, mainly in the hours following the afternoon meal. Recording was repeated after 3 weeks of treatment with propranolol, 40 mg t.i.d. In patient 1, beta blockade drastically reduced the number and severity of hypotensive episodes, while propranolol failed to control blood pressure in patient 2, who experienced a higher number of hypotensive events during treatment. Findings of this study may be relevant to the management of patients with orthostatic hypotension and should contribute to a more accurate characterization of blood pressure profile in autonomic dysfunction.

Blood Pressure↗
PubMed1985

Asymptomatic transient ST changes during ambulatory ECG monitoring in diabetic patients.

The reported higher incidence of painless myocardial infarction in diabetic patients suggests that asymptomatic transient myocardial ischemia may also be frequent in diabetes. To explore this possibility 51 subjects with type II diabetes, aged 43 to 71 years (mean +/- SEM 56 +/- 8), 70 nondiabetic patients with coronary artery disease (mean age 55 +/- 5), and 40 nondiabetic patients without overt coronary disease (age 54 +/- 9) were studied. Thirty-eight of the 51 diabetic patients (74%) had evidence of associated coronary disease and 19 (37%) had evidence of previous myocardial infarction. All subjects underwent continuous 24-hour ambulatory ECG monitoring. In 18 of 51 diabetic patients 93 episodes (73% of the total number) of asymptomatic ST segment changes were recorded; the total number of symptomatic episodes was 36, and they were observed in seven patients (27%). Forty-eight (60%) asymptomatic and 32 symptomatic episodes of significant ST changes were found in nondiabetic patients with coronary artery disease. When patients with previous myocardial infarction were examined separately, asymptomatic episodes of significant ST changes were observed in 10 of 19 diabetic patients and in 5 of 25 nondiabetic patients with coronary artery disease (p less than 0.05). In an additional 28 diabetic patients who underwent exercise stress test, 15 exhibited an abnormal ECG response; however, only five of them (33%) were symptomatic. This study suggests that the incidence of transitory myocardial ischemia, as assessed by ambulatory ECG monitoring and exercise stress test, is higher in type II diabetic patients than in nondiabetic control subjects with coronary artery disease.

Adult↗
PubMed1985

[Mepindolol reduction of the degradation of phospholipids and the necrosis induced by myocardial ischemia].

Mepindolol is a newly developed beta-adrenergic blocking agent, which differs from other available beta-blockers in its ability to counteract the chronotropic effect of catecholamines without depressing myocardial contractility. This study was designed to assess whether mepindolol administration is effective in reducing infarct size. Accordingly, 53 rats were randomly assigned to 3 groups: group 1 (n = 16) underwent coronary artery occlusion without receiving any treatment, and was used as control; group 2 (n = 19) was treated with mepindolol (1 mg/kg s.c.) 5 min and every 8 hours after occlusion, for 48 hours; group 3 (n = 18) underwent a sham-operation. No difference in mortality was found among groups. The animals were sacrificed 48 hours after occlusion and the left ventricle homogenized and centrifuged. Infarct size was calculated from the residual creatine phosphokinase activity, and found to average 52.4 +/- 7.8% (mean +/- SEM) of the left ventricle in control rats and 35.6 +/- 5.4% in treated rats (p less than 0.05), indicating a 32.1% reduction of infarct size. The phospholipid content of the supernatants was also measured: it averaged 0.08 microgram P/mg of protein in sham-operated rats and 0.61 + 0.04 micrograms P/mg of protein in control animals, showing that coronary ligation induced a degradation of myocardial phospholipids. Mepindolol-treated rats, however, showed a phospholipid concentration of 0.70 +/- 0.04 microgram P/mg of protein (p less than 0.05), suggesting that the drug was able to prevent ischemia-induced phospholipase activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1985

[Limitation of the area of necrosis induced by quinacrine after coronary occlusion in the dog].

Phospholipase activation has been suggested to represent one of the most relevant biochemical steps toward irreversible myocardial injury during ischemia. Accordingly, the time-course of myocardial phospholipid degradation was studied in 167 rats surviving coronary artery occlusion randomly divided into 83 controls and 84 treated with the phospholipase inhibitor quinacrine (75 mg/Kg s.c. every 8 h). The animals were sacrificed at different times ranging from 2 to 48 h post-occlusion and phospholipids and creatine kinase activity (CK) were measured on the supernatant of the left ventricular homogenates. In control animals a rapid fall in phospholipid concentration (from 1.33 +/- 0.12 to 0.67 +/- 0.05 microgram P/mg of protein) and CK activity (from 9.84 +/- 0.49 to 6.93 +/- 0.60 IU/mg of protein) was observed within 4 hours post-occlusion; these parameters remained almost unchanged throughout the rest of the study. In quinacrine-treated animals left ventricular phospholipids and CK also fell during the first hours post-occlusion; however, 24 and 48 h after the occlusion they were significantly higher than in controls (phospholipids: 0.99 +/- 0.05 vs 0.62 +/- 0.04 microgram P/mg of protein, p less than 0.001, and CK: 7.76 +/- 0.54 vs 4.99 +/- 0.37 IU/mg of protein, p less than 0.001, at 48 h). The effect of quinacrine on the extent of necrosis was then assessed in 13 anesthetized dogs undergoing ligation of the left anterior descending coronary artery. To measure the area at risk (RZ), 99Tc-PP labeled albumin microspheres were injected into the left atrium 5 min after coronary occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗