186,328 research outputs found
Reduced aerobic metabolic efficiency in postischemic myocardium dysfunction in rats: role of aging.
No full textAge-related effects of platelet activating factor (PAF) in the isolated perfused rat heart.
No full textPlatelet Activating Factor (PAF) is a phospholipid that has been implicated as an
important mediator of anaphylactic cardiac dysfunction and involved in the toxic
effects of the ischaemia-reperfusion process. In the elderly, these phenomena are
thought to be exaggerated by the age-related changes in response to several
chemical factors and myocardial ischaemia. We evaluated the effects of PAF
(acetyl-o-alkyl-l-phosphatidylcholine) on left ventricular systolic (LVSP) and
diastolic (LVDP) pressure, coronary flow rate (CFR) and heart rate (HR) in adult
(6 months, AH) and senescent (24 months, SH) rat hearts. The perfusion of PAF
(10(-8), 10(-7) and 10(-6) M) induced a concentration-related reduction of LVSP,
CFR and HR and a linear increase in LVDP. Contractile modifications were more
pronounced in senescent hearts: LVSP decreased (P < 0.01) and LVDP increased with
respect to younger animals (P < 0.01 vs. AH). This negative inotropic effect was
also present in electrically paced hearts. PAF produced conduction arrhythmias
ranging from second-degree atrio-ventricular conduction block to cardiac
standstill both in adult and senescent hearts; at a higher dose (10(-6) M),
cardiac standstill appeared after 96.5 +/- 15.3 s in adult hearts and after 45.5
+/- 17.6 s in senescent hearts (P < 0.01). Lyso-PAF did not modify while specific
PAF antagonist compounds CV-3988 inhibited all electromechanical responses both
in adult and senescent hearts. These data suggest that age influences the effect
of PAF on contractile parameters, coronary flow and conduction arrhythmias by acting on receptors, whose function is unaffected by age
Dipyridamole echocardiography as a useful and safe test in the assessment of coronary artery disease in the elderly
No full textWe prospectively studied the sensitivity, specificity, feasibility, and safety of high-dose dipyridamole echocardiography, compared to exercise electrocardiography in 130 subjects (67 younger and 63 elderly patients) referred for angiographic
evaluation of suspected or proven coronary artery disease. Sensitivity, specificity, and feasibility of dipyridamole echocardiography were respectively 75.5%, 100%, and 88.0% in younger patients and 82.9%, 100%, and 79.4% in elderly patients (P = NS). The sensitivity of exercise electrocardiography was 72.7% in young and 66.6% in elderly patients (P = NS); specificity 66.0% vs 60.0% (P = NS); feasibility 83.6 vs 63.5 (P = 0.05). Forty-nine younger and 38 elderly patients performed both tests. Sensitivity of dipyridamole echocardiography compared to exercise electrocardiography was 76.2% vs 73.8% in young patients and 83.3% vs 70% in the older group (P = NS). The feasibility of the two tests was significantly different in the elderly group only (dipyridamole echocardiography 79.4% vs exercise electrocardiography 63.5%; P less than 0.01). The incidence of side effects during dipyridamole echocardiography was similar in the two groups, except for dyspnea which was observed in 20% of older and 5% of younger patients
(P less than 0.05). Our data demonstrate that the dipyridamole test combined with
echocardiographic monitoring of regional myocardial contractility may be considered a valid non-invasive method for evaluating coronary artery disease in the elderly and that this test is a satisfactory alternative to the exercise stress test
Arrhythmogenic age-related effects of lysophosphatidylcholine in the rat heart.
No full textVentricular arrhythmias are the most common cause of death among patients with coronary artery disease; this is more evident in the elderly, who tend to have
more severe coronary artery disease and age-dependent modifications of cardiac electrophysiology. Lysophosphoglycerides, which accumulate in the ischemic
myocardium, are responsible for oscillatory after-potentials and may contribute to the development of ventricular arrhythmias. The aim of this study was to
examine the effects of lysophosphatidylcholine (5 x 10(-5) M) in the absence or presence of epinephrine (10(-6) M) in isolated, perfused hearts from adult (6-12 months old) and senescent (24 months old) rats. Rat hearts (30/group) were randomly divided into four groups each of which included hearts of 6, 12 and 24-month old rats. The groups comprised a control group, a group treated with epinephrine, a group treated with lysophosphatidylcholine and a group treated
with both epinephrine and lysophosphatidylcholine. Analysis of arrhythmias indicated a linear correlation between epinephrine- and lysophosphatidylcholine-induced ventricular arrhythmias and age. The incidence of
arrhythmias was higher in the hearts treated with epinephrine and lysophosphatidylcholine together than in those treated with either substance separately (p less than 0.01). The results indicate that age influences the
arrhythmogenic action of lysophosphatidylcholine, and that epinephrine contributes to this effect
Echocardiographic vs hemodynamic monitoring during isometric exercise in patients with coronary artery disease.
No full textBACKGROUND: Isometric exercise is able to induce myocardial asynergies in patients with coronary artery disease as demonstrated by noninvasive monitoring
performed during stimulation.
AIMS OF THE STUDY: In the present study, a combined echocardiographic and hemodynamic monitoring of left ventricular contractility has been conducted in order to verify, with invasive and noninvasive techniques, the ability of isometric exercise in inducing transient myocardial ischemic phenomena.
METHODS: The study population was composed of 20 patients with angiographic evidence of significant coronary stenosis (> or = 50%), and 10 subjects with normal coronary angiograms. All 30 subjects admitted to the study underwent an isometric exercise stress during echocardiographic and hemodynamic monitoring of left ventricular contractility.
RESULTS: Nine out of 20 patients with coronary disease showed regional asynergy during the test (Group I). The remaining 11 patients showed normal myocardial contractility (Group II). None of the 10 control subjects showed mechanical signs of ischemia during the test. Left ventricular end diastolic pressure significantly increased in both Group I (10 +/- 2 to 24 +/- 4 mmHg) and Group II
(12 +/- 3 to 26 +/- 3 mmHg) (p < 0.01) while it remained unchanged in the control group (9 +/- 2 to 13 +/- 2 mmHg; p = NS); dp/dt increase (% basal) was
significantly higher in the control group (45 +/- 6%) than in either Group I (25 +/- 3%) or Group II (26 +/- 3%) (p < 0.01).
CONCLUSIONS: Isometric exercise was able to induce left ventricular asynergies due to regional myocardial ischemia. Hemodynamic contractility monitoring easily
distinguished the control subjects from the patients with coronary disease but was not able to discriminate patients with handgrip-induced regional asynergy.
Thus, the echocardiographic technique offers more detailed information about regional myocardial function than do the common hemodynamic contractility indexes
Combined approach with negative pressure wound therapy and dermal substitute for extravasation injury: Why can't they be friends?
No full textThe role of aging on ouabain- and epinine-induced ventricular arrhythmias in isolated rat heart
No full textEffect of flecainide acetate on reperfusion- and barium-induced ventricular tachyarrhythmias in the isolated perfused rat heart.
No full textFlecainide acetate is a new antiarrhythmic drug which suppresses different kinds
of experimental arrhythmias. We studied the efficacy of flecainide acetate on
reperfusion- and barium-induced ventricular tachyarrhythmias in the isolated
perfused rat heart by monitoring heart rate, coronary flow rate, left ventricular
systolic pressure, dp/dtmax, and the voltage of the epicardial electrogram.
Seventy-five male rats were randomized into 5 groups. In group I, after a 15 min
period of stabilization, hearts were perfused by ischemic perfusion and then
reperfused. In group II, flecainide acetate (10(-6) M) was given after
stabilization and before ischaemic perfusion. In group III, barium chloride
(10(-3) M) was given after stabilization. In group IV, flecainide acetate was
given after stabilization and before barium chloride administration. In group V,
acetylcholine chloride (10(-6) M) was given after stabilization and before barium
chloride administration. In group I, we noted during ischemia a reduction in
heart rate, coronary flow rate, left ventricular systolic pressure and dp/dtmax
and an increase in the voltage of the epicardial electrogram. In group II, after
administration of flecainide acetate, we observed a reduction in heart rate, left
ventricular systolic pressure and dp/dtmax; during the ischaemic period there was
no difference in these parameters with respect to group I. Reperfusion induced
ventricular arrhythmias in 12 out of 15 hearts in group I and in only 3 out of 15
in group II (p less than 0.005). Barium induced ventricular arrhythmias in the 15
hearts studied in group III as well as in group IV. On the contrary,
acetylcholine chloride in group V prevented the occurrence of barium-induced
ventricular arrhythmias (p less than 0.005 vs group III and IV). Thus, flecainide
acetate is able to reduce reperfusion-induced ventricular arrhythmias, but is
unable to reduce barium-induced ventricular arrhythmias, presumably because of a
different mechanism of these two types of arrhythmia
Modificazioni elettro-meccaniche indotte dal fattore di attivazione piastrinico (PAF) nel cuore di ratto isolato e perfuso: effetto dell’invecchiamento
No full textProtective effect of beta-blockade on dipyridamole-induced myocardial ischaemia. Role of heart rate.
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