Carlo Manca

Abnormal ventricular repolarization mimicking myocardial infarction after heterocyclic antidepressant overdose.

In 2 young adult women who experienced acute heterocyclic antidepressant intoxication, we found a quite unusual electrocardiographic pattern characterized by abnormal ST-tract elevation in the right precordial leads associated with a marked QRS widening (right bundle branch block and left anterior fascicular block type). Because serum electrolyte imbalance and acute myocardial ischemic events were excluded, the mechanism by which antidepressant overdose may produce such elevation of the ST tract remains unclear.

Different Prognostic Value of Exercise Electrocardiogram in Men and Women

In 1,455 subjects (947 men and 508 women) who underwent a bicycle ergometer stress test for evaluation of atypical chest pain, the incidence of coronary events (definite myocardial infarction or sudden death) was assessed by the life table method. The follow-up period ranged from 3 to 7 years (mean 5.2 years). In men with positive exercise test (ischemic ST depression greater than or equal to 1 mm), the 5-year incidence of coronary events was 18.3%, compared with 1.9% in negative responders. In women with positive response, the 5-year incidence of coronary events was 4.6%; in negative responders, it was 0.3%. The poor predictive value of ischemic ST responses to exercise in women is emphasized.

The effects of transdermal estradiol on the response to mental stress in postmenopausal women: a randomized trial

PURPOSE Estrogens inhibit adrenomedullary catecholamine release and catecholamine-mediated responses to stress. We examined whether estrogen supplementation reduces the sympathoadrenal response to mental stress in postmenopausal women. MATERIALS AND METHODS We compared the effects of 3-week treatment with transdermal 17-beta-estradiol and placebo in 10 postmenopausal women using a randomized, blinded, crossover design. We measured plasma catecholamine levels and the cardiovascular and metabolic responses to a 15-minute stress with mental arithmetic. Treatments were compared using repeated measures analysis of variance. RESULTS During placebo treatment, mean (+/- SD) epinephrine levels reached a peak of 431 +/- 135 pmol/liter after 15 minutes of stress; the epinephrine response was blunted during estradiol treatment, with a peak of 357 +/- 77 pmol/liter (P <0.05). Estradiol also blunted the diastolic blood pressure response to stress (baseline levels of 78 +/- 15 mm Hg vs peak of 90 +/- 6 mm Hg during placebo; baseline of 80 +/- 8 mm Hg vs peak of 84 +/- 6 mm Hg during estradiol; P <0.05). Estradiol treatment also blunted the decrease in the standard deviation of the mean of the electrocardiographic RR intervals and the increase in the ratio between the low-frequency and high-frequency bandwidths. CONCLUSION We observed a moderate, although significant, reduction in markers of the stress response to mental arithmetic in postmenopausal women treated with transdermal 17-beta-estradiol.

Newer data on the configuration and variability ranges of body surface maps in a sample of normal subjects

Quantitative data on the normal variability of body surface maps (BSM) are scarce in the literature. This is one of the reasons why BSM are not yet widely used in clinical practice despite their superior information contents. In this study we determined the average value and variability of a number of parameters derived from BSM in a group of 36 normal adult males, ages 22 to 60. Forty to 60 homogeneous beats were averaged for each subject. This enabled us to extend our study to the low voltage intervals (P,PQ,ST,U) which encompass more than 60% of the entire P-U duration and to contribute new data to controversial issues, such as the presence of two simultaneous maxima during atrial excitation. The following parameters were measured: a) the coordinates of the absolute potential maximum and minimum on the chest surface during the entire cardiac cycle; b) the time course of four voltage-related functions, namely: highest instantaneous potential value on the chest surface, lowest (most negative) potential, highest potential difference, and surface integral of the absolute value of the potential function. In recent studies these parameters were shown to be of considerable value in discriminating normal subjects from different categories of cardiac patients.

Comparison of Five Different Stress Testing Methods in the ECG Diagnosis of Coronary Artery Disease

Five different stress testing methods: bicycle ergometer exercise (BE), treadmill exercise (TD), isoproterenol infusion test (IPN), dopamine infusion test (DPM), and atrial pacing (AP), were performed on 90 male patients who underwent coronary arteriography. Ischemic S-T segment depression of 1.0 mm or greater was used as the criterion for a positive test. Within the group of 56 subjects having significant coronary artery disease (CAD) the diagnostic sensitivity of the single tests was as follows: 64.3% for BE, 66.1% for TD, 69.6% for IPN, 41.1% for DPM, 75.0% for AP. For the 34 subjects with no CAD the folowing specificity was found: 88.2% for BE and for TD, 82.3% for IPN, 85.3% for DPM, 63.8% for AP. When the results of the different tests were combined, it was seen that the association of an ergometric test with IPN enhanced the sensitivity of the exercise test (p less than 0.05) without significantly decreasing the specificity.

Effects of verapamil and nifedipine on rate of left ventricular relaxation in coronary arterial disease patients

We have evaluated the effects of nifedipine and verapamil on rate of left ventricular relaxation in 26 patients having coronary arterial disease with normal ejection fraction and normal left ventricular contractility. None of the patients had myocardial infarction. All patients showed normal contractile indices and abnormally high values of T constant, neg, dP/dt and left ventricular protodiastolic pressure, suggesting an impairment of left ventricular relaxation. Nifedipine, injected intravenously (15 micrograms/kg) in 14 patients induced a significant reduction of afterload parameters and an increase of contractility. Nifedipine also improved left ventricular relaxation, as it induced a reduction of the T constant from 42 +/- 2 msec to 33 +/- 2 msec (P less than 0.01). It induced a tendency to a reduction of negative dP/dt and protodiastolic pressure without reaching statistical significance. Verapamil, injected intravenously in the remaining 12 patients (0.1 mg/kg as a bolus followed by chronic infusion of 0.005 mg/kg/min for 3 min) induced a reduction of the T constant from 43 +/- 10 to 37 +/- 6 msec (P less than 0.01). It reduced the negativity of dP/dt from 2302 +/- 273 to 2021 +/- 252 mm Hg/sec (P less than 0.05) and of left ventricular protodiastolic pressure from 3.2 +/- 1.4 to 1.5 +/- 1.1 mm Hg (P less than 0.01). Verapamil, like nifedipine, reduced the afterload parameters although to a lesser extent. It did not substantially affect the left ventricular contractility. These data suggest that abnormalities of left ventricular relaxation may precede changes in systolic function and that nifedipine and verapamil favourably modify the indices of left ventricular diastolic function in patients with coronary arterial disease.

Effects of acute k-strophantidin administration on left ventricular relaxation and filling phase in coronary artery disease

In 10 patients with coronary artery disease, preserved left ventricular (LV) performance and absence of previous myocardial infarction, the effects of an acute intravenous administration of k-strophantidin (0.005 mg/kg over 10 minutes) on selected parameters of both LV systolic and diastolic function, including relaxation, were evaluated. An increase in positive first derivative of LV pressure (dP/dt) and in the ratio between dP/dt and the pressure developed (dP/dt/P) (1,530 +/- 287) 1,600 +/- 329 mm Hg/s [p less than 0.05], and 30 +/- 6 to 34 +/- 8 s-1 [p less than 0.05], respectively) demonstrated the inotropic effect of k-strophantidin, whereas volumetric parameters of systolic function (end-systolic and stroke volume indexes, and ejection fraction) did not show any significant change. However, LV relaxation was impaired by k-strophantidin injection; in fact, mean values of T constant were significantly increased from 50 +/- 12 to 55 +/- 13 ms (p less than 0.01). Lowest LV and end-diastolic pressures increased from 8 +/- 4 to 11 +/- 4 mm Hg (p less than 0.05) and from 17 +/- 6 to 20 +/- 8 mm Hg (p less than 0.05), respectively. The end-diastolic volume and maximal rate of volumetric increase during the early and late filling phases were not modified by k-strophantidin. Mean aortic pressure increased from 110 +/- 10 to 120 +/- 12 mm Hg (p less than 0.001). Therefore, in patients with coronary artery disease and LV preserved performance, an acute intravenous administration of k-strophantidin appears to stimulate contractility and to worsen relaxation, and minimal LV and end-diastolic pressures.

Lack of tolerance development during chronic ibopamine administration to patients with congestive heart failure.

SummaryBeta-adrenergic agonists can progressively lose their efficacy during chronic therapy in patients with heart failure. Ibopamine is a new dopamine derivative, active on dopaminergic and beta-adrenergic receptors, whose hemodynamic activity has been acutely demonstrated. To assess whether any attenuation of its efficacy occurs, the variations of the cardiac output induced during chronic therapy were monitored by impedance cardiography in 15 patients with dilated cardiomyopathy who showed a significant increase of the cardiac output (20.7 ± 10.0%) after acute ibopamine administration. The efficacy of ibopamine was also assessed after 6 and 12 months of therapy by echocardiography, exercise testing, and 24-hour dynamic electrocardiogram (EKG) monitoring.The cardiac output response to ibopamine did not show any significant attenuation (range 15% to 19%) in the evaluations at 1, 2, 3, 4, 8, and 12 months of therapy. No significant change, was noted, after 6 and 12 months, in the exercise capacity (505 vs. 602 and 604 seconds) and the fractional shortening (16.2 vs. 18.3 and 18.5) without any change of the diastolic diameter. Ventricular arrhythmias were significantly reduced after 6, but not 12, months of therapy. No significant change in the New York Heart Association (NYHA) functional class was noted at 6 and 12 months of therapy (2.4 ± 5 vs. 2.3 ± 7 and 2.4 ± 0.6, respectively). Our results show that ibopamine can maintain its hemodynamic activity even during chronic therapy.

Non invasive evaluation of left ventricular performance in 294 diabetic patients without clinical heart disease

SummaryThe authors studied the modification of systolic time intervals (STI), pre-ejection period (PEP) and left ventricular ejection time (LVETc), before and after isometric exercise, in 294 diabetic patients without clinical evidence of cardiomyopathy and in good metabolic control compared to 132 normal subjects. The study was aimed at detecting preclinical alterations of left ventricular function. Diabetic patients considered together did not show any difference in STI in basal conditions or after isometric exercise compared to normal subjects. When diabetic patients were divided into sub-groups according to their treatment, the insulin-treated diabetics showed modification of STI after isometric exercise, which indicated an alteration of left ventricular function. Also subjects treated with oral hypoglycemic agents showed similar but less evident changes. In diabetic patients on diet only and in those with duration of diabetes of 6 months or less, STI was identical to that of normal subjects. These data do not explain the pathogenesis of myocardial involvement, although they are in accordance with studies which have laid emphasis on the alteration of compliance of the diabetic heart.

Stented versus stentless bioprostheses in aortic valve stenosis: effect on left ventricular remodelling.

BACKGROUND Whether the use of stentless aortic bioprostheses improves hemodynamics more than stented bioprostheses in the small aortic root is still a matter of debate. METHODS Early- and mid-term effects were compared between 2 different types of stentless bioprotheses and 1 type of stented bioprosthesis for left ventricular remodelling. The effects of the bioprotheses were studied by echocardiography in 68 patients (age, 74 +/- 7 years) with aortic annulus diameter < or =23 mm who were undergoing prosthesis implantation due to aortic isolated stenosis. Stented bioprostheses (Carpentier-Edwards Perimount [CEP]) were implanted in 36 subjects and stentless bioprostheses (18 Toronto SPV and 14 Shelhigh Super Stentless) were implanted in 32 subjects. RESULTS A progressive and similar decrease in left ventricular mass of 30% was observed in both stented and stentless bioprostheses at 12 months. A progressive increase in transprosthetic effective orifice area and a decrease in transprothetic pressure gradient were observed at 3, 6, and 12 months in the Toronto group, but these variables showed improvement only at 3 months in the CEP and Shelhigh groups. No mortality occurred during surgery or during the 1-year follow-up period. CONCLUSIONS Our results confirmed good feasibility of aortic stented and stentless bioprostheses implantation in the elderly population. A 30% decrease in left ventricular mass occurred in the early- and mid-term (12 months) periods after surgery with all 3 types of bioprostheses. Advantages consisting of a progressive increase in transprosthetic effective orifice area and a decrease of the transprosthetic pressure gradient were observed in the Toronto group in comparison to the CEP and Shelhigh groups. These observations may help surgeons in choosing bioprostheses.