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Biomedical subjects

A Iacono

Publications and source records attributed to A Iacono.

At least 73 records · Page 4Linked to original sources

[Electrophysiological analysis of atrioventricular and intraventricular conduction in bi- and tri-fascicular blocks].

We have evaluated, at baseline and during incremental atrial pacing (AP), intracardiac conduction features of 53 patients with electrocardiographic diagnosis of bifascicular or trifascicular block, free from any pharmacological treatment potentially able to affect atrioventricular (AV) conduction system properties. The patients have been subdivided in the following groups: group A (13 patients), with LBBB and a PQ interval > or = 200 msec; group B (14 patients), with RBBB, LAH with a PQ interval > or = 200 msec; group C (8 patients), with LBBB and a PQ < 200 msec; group D (15 patients), with RBBB, LAH and a PQ < 200 msec; group E (3 patients), with RBBB, LPH and a PQ < 200 msec. In group A, 31% presented a long AH interval (> 140 msec), while 85% showed an increased infra-his conduction time (HV > 55 msec). During AP, only 38.5% maintained a 1:1 AV conduction ratio up to 140 bpm, while 30.8% developed an infra-his Mobitz 2 2nd degree AV block. 15.4% an infrahis 2:1 2nd degree AV block, 15.4% an AV nodal Mobitz 2 2nd degree AV block. In group B, 64% and 29% exhibited respectively an AV nodal and an infrahis conduction delay. During AP, 57.1% maintained a 1:1 AV conduction ratio up to 140 bpm, 14.3% developed an AV nodal Mobitz 1 2nd degree AV block, 14.3% an infrahis Mobitz 1 2nd degree AV block, 7.1% an AV nodal 2:1 2nd degree AV block, 7.1% an infrahis Mobitz 2 2nd degree AV block. In group C, no patient manifested a prolonged AH interval, while 50% exhibited a HV > 55 msec. 62.5% maintained a 1:1 AV conduction ratio up to 140 bpm, 25% developed an AV nodal Mobitz 1 2nd degree AV block and 12.5% an infrahis 2:1 2nd degree AV block. In group D, no patient showed an increased AH interval and only 13% presented a HV interval exceeding 55 msec. During AP, 86.7% maintained a 1:1 AV conduction ratio up to 140 bpm, 6.6% developed an AV nodal Mobitz 1 2nd degree AV block, 6.6% an infrahis 2:1 2nd degree AV block. In group E, no patient showed a prolonged AH interval, while 2/3 (66.6%) exhibited an infrahis conduction delay. During AP, 100% developed an infrahis 2:1 2nd degree AV block. Considering all patients with LBBB (groups A+C) and with RBBB+LAH (groups B+D), no differences were found in terms of PQ, PA and AH intervals, even though, concerning patients with a long PQ (group A vs group B), AH interval resulted significantly longer in patients with RBBB+LAH (121.85 +/- 36.4 msec vs 163.29 +/- 55.96 msec, p = 0.031). Infrahis conduction, independently from the measurement adopted (HVI interval: from the beginning of the His to the onset of the ventricular electrogram recorded at the His region; HV2 interval: from the beginning of the His to the onset of the surface QRS), resulted more compromised in patients with LBBB than in patients with RBBB+LAH (HVI: 75.24 +/- 40.23 msec vs 50.79 +/- 25.16 msec, p = 0.011; HV2: 77.24 +/- 38.12 msec vs 53.92 +/- 29.3 msec, p = 0.015). Such a difference became even more significant when comparing the percentage of patients with a prolonged HV interval (average value > 55 msec) in the above mentioned groups: 71.4% in case of LBBB, 20.7% in case of RBBB+LAH (p < 0.001). Regarding intraventricular conduction (IV), no statistically significant differences were found. In patients with RBBB+LAH, IV was not related to infrahis conduction time and PQ interval appeared more related to AH (r = 0.838, p < 0.001) than to HV (PQ-HV1: r = 0.381, p = 0.041, PQ-HV2: r = 0.474, p = 0.009). Conversely, in patients with LBBB infrahis and IV conduction appeared linearly related (HVI-V: r = 0.416, p = 0.06; HV2-V: r = 0.445, p = 0.043). As for PQ interval, it resulted more closely related to infrahis conduction (PQ-HVI: r = 0.626, p = 0.002; PQ-HV2: r = 0.674, p < 0.001), than to AH (r = 0.533, p = 0.013). In conclusion, infrahis conduction resulted more impaired in patients with LBBB. In this group, differently from patients with RBBB+LAH, infrahis conduction seems to affect the degree of IV conduction delay. (ABST

Aged↗

[Effectiveness and tolerability of bisoprolol vs. nifedipine in uremic patients with ischemic cardiopathy in dialysis treatment].

The effects of bisoprolol on transient myocardial ischemia have been compared with those of nifedipine in patients with coronary artery disease in end-stage renal failure maintained on haemodialysis. We also evaluated the tolerability of both drugs. Sixty patients (42 males, 18 females, mean age 52 +/- 4 years) in renal failure maintained on haemodialysis, with coronary artery disease and more than four significant episodes of transient myocardial ischemia (> or = 1 min) during 48-hour Holter monitoring, were included in the study. All cardiovascular drugs were discontinued > or = 6 days before this 48-hour ambulatory ECG monitoring, with the exception of sublingual nitrates allowed for relief of anginal attacks. Patients were then randomized to receive either bisoprolol or nifedipine for 2 weeks. After a 15-day wash-out period, they were crossed over to receive either bisoprolol or nifedipine for other 2 weeks. Statistical analysis was carried out using the Student's t test. A p value < 0.01 was considered significant. Both bisoprolol and nifedipine reduced number and duration of transient ischemic episodes as well as the total ischemic burden. Reductions were statistically significant for both antianginal drugs. Only bisoprolol was effective in silent ischemia (p < 0.001). It also reduced heart rate (p < 0.001), while nifedipine raised it (p < 0.001). Both drugs reduced systolic and diastolic blood pressure. The circadian variations of transient ischemic episodes showed two peaks in the 24 hours. Both peaks were reduced with bisoprolol. Nifedipine brought a clear overall reduction in the number of episodes but the circadian pattern was unchanged. During the study, 10 patients taking bisoprolol and 12 patients taking nifedipine had drug adverse effects. No one of them had to be withdrawn from treatment. In conclusion, bisoprolol seems to be more useful than nifedipine because its effects, in transient ischemic episodes, are greatly superior to those of nifedipine, and because it is effective also in silent ischemia. Both drugs showed a good tolerability in these patients. Bisoprolol, reducing the two daily peaks of ischemic episodes frequency, has a protective role towards mortality due to coronary artery disease.

Adrenergic beta-Antagonists↗

[Acute hepatitis following amiodarone administration].

A 61 year old man, treated with amiodarone since 1993 for resistant supraventricular arrhythmias, developed acute hepatitis after an intravenous amiodarone administration. Kidney and liver function tests were performed and pointed out abnormal results. Symptoms ascribable to hepatotoxicity were absent. These changes returned to normal levels within 20 days from withdrawal of the drug. Amiodarone hepatotoxicity can be related to prolonged therapy with a high dose. Intravenous amiodarone may cause acute hepatic disease, but it is suggested that polysorbate 80, a solvent added to the intravenous infusion, is a more likely cause of this complication.

Acute Disease↗

Mean-term calcium heparin treatment in acute transmural anterior myocardial infarction: effects on left ventricular thrombosis and its complications.

In order to assess the efficacy of 3-month subcutaneous treatment with calcium heparin 12,500 IU twice daily in preventing left ventricular thrombosis and its complications a prospective, controlled, randomized trial was carried out in 204 patients with acute anterior myocardial infarction consecutively enrolled in seven Italian hospitals. Left ventricular thrombosis was diagnosed by means of two-dimensional echocardiography performed at baseline, after 10 and 90 days of treatment. The incidence of thrombosis at the baseline echocardiogram was not significantly different between the treatment and control groups, whereas a significantly lower incidence of thrombi was observed in treated than in control group both on day 10 (3/86, 3.5% and 13/85, 15.3%, respectively; p < 0.05) and day 90 (1/65, 1.5% and 6/57, 10.5%, respectively; p < 0.05). The total incidence of thrombi after 3 months of therapy was significantly lower in calcium heparin-treated patients (19/106, 17.9%) than in controls (31/98, 31.6%; p < 0.05). The incidence of cardiac events (death, reinfarction, angina) in the two groups during the 3-month treatment period was not significantly different. Two embolic events, one cerebral and one pulmonary, occurred in the control group, both after day 10 of treatment.

Anticoagulants↗

Increased dispersion of ventricular recovery time as a new repolarization abnormality in the Wolff-Parkinson-White syndrome.

The aim of our study was to assess whether the presence of ventricular preexcitation affects the spatial distribution of ventricular recovery time. Recent reports support the hypothesis that QT and QTc dispersions (QTd and QTcd) can be reliably adopted as a non-invasive parameter to estimate regional discrepancies of ventricular repolarization. The ECGs of 32 healthy subjects with Wolff-Parkinson-White syndrome and of 29 normal individuals have been analysed using a Digitizer (Calcomp 9000), in order to obtain, for each subject, a mean QRS (M-QRS), QT (M-QTe), QTc (M-QTec), JT (M-JT), JTc (M-JTc) from all the measured intervals of the 12 standard ECG leads. QRS, QT and QTc dispersions (QRSd, QTd, QTcd) were defined as the difference between the maximal and minimal QRS, QTe and Qtec values calculated in the various leads. We attained the following results: patients with WPW syndrome exhibited, with respect to controls, longer M-QRS (P < 0.001) and M-QTec (P < 0.001) values, despite similar M-QTe (P = NS), M-JT (P = NS) and M-JTc (P = NS). QRSd did not differ in the two groups(P = NS), while QTd and QTcd both resulted significantly greater in pre-excited subjects (P < 0.001). In the WPW group, QRSd was not related either to QTd (r = 0.325, P = NS) or to QTcd (r = 0.148, P = NS), while in the controls there was a significant relation between QRSd and both QTd (r = 0.522, P = 0.004) and QTcd (r = 0.379, P = 0.042). Our findings suggest that the presence of ventricular pre-excitation does not determine a prolongation of the mean ventricular recovery time, but increases regional discrepancies of the re-polarization process. This assumption is supported by the observation of greater values of QTd and QTcd associated with a similar QRSd.

Adult↗

Ionic mechanisms of ischemia-related ventricular arrhythmias.

The aim of this review is the utmost simplification of the cellular electrophysiologic background of ischemia-related arrhythmias. In the acute and subacute phase of myocardial infarction, arrhythmias can be caused by an abnormal impulse generation, abnormal automaticity or triggered activity caused by early or delayed afterdepolarizations (EAD and DAD), or by abnormalities of impulse conduction (i.e., reentry). This paper addresses therapeutic intervention aimed at preventing the depolarization of "pathologic" slow fibers, counteracting the inward calcium (Ca) influx that takes place through the L-type channels (Ca antagonists), or hyperpolarizing the diastolic membrane action potential, increasing potassium (K) efflux (K-channel openers) in arrhythmias generated by an abnormal automaticity (ectopic tachycardias or accelerated idioventricular rhythms). If the cause enhanced impulse generation is related to triggered activity, and since both EAD and DAD are dependent on calcium currents that can appear during a delayed repolarization, the therapeutic options are to shorten the repolarization phase through K-channel openers or Ca antagonists, or to suppress the inward currents directly responsible for the afterdepolarization with Ca blockers. Magnesium seems to represent a reasonable choice, as it is able to shorten the action potential duration and to function as a Ca antagonist. Abnormalities of impulse conduction (re-entry) account for the remainder of arrhythmias that occur in the acute and subacute phase of ischemia and for most dysrhythmias that develop during the chronic phase. Reentrant circuits due to ischemia are usually Na channel-dependent. Drug choice will depend on the length of the excitable gap: in case of a short gap (ventricular fibrillation, polymorphic ventricular tachycardia, etc.), the refractory period has been identified as the most vulnerable parameter, and therefore a correct therapeutic approach will be based on drugs able to prolong the effective refractory period (K-channel blockers, such as class III antiarrhythmic drugs); on the other hand, for those arrhythmias characterized by a long excitable gap (most of the monomorphic ventricular tachycardias), the most appropriate therapeutic intervention consists of depressing ventricular excit-ability and conduction by use of sodium-channel blockers such as mexiletine and lidocaine. Compared with other class I antiarrhythmic agents, these drugs minimally affect refractoriness and exhibit a use-dependent effect and a voltage dependent action (i.e., more pronounced on the ischemic tissue because of its partial depolarization).

Animals↗

Left ventricular performance and autonomic dysfunction in patients with long-term insulin-dependent diabetes mellitus.

Cardiac autonomic neuropathy (CAN) is a very frequent complication of insulin-dependent mellitus type 1, affecting the sympathetic or parasympathetic sections or both. The different impairment in the two sections might modify left ventricular function early. To evaluate this relationship, we studied 61 patients (mean age 39.6 +/- 7 years) with type 1 diabetes for more than 10 years, without coronary artery disease (CAD); negative ergometric stress test) and without other pathologies that could interfere with ventricular function. All patients underwent MONO-, 2-dimensional and Doppler echocardiographic examination and radionuclide angiography with 99Tc (RNA). According to the outcome of the Ewing tests, patients were divided into two groups: group A with two or more tests altered (26 patients with CAN) and group B with one or no tests altered (35 patients without CAN). No significant differences between the two groups were found in the systolic function parameters with either technique. In contrast, a pattern of abnormal relaxation was found for the diastolic function parameters: in group A a decrease in E-wave velocity and its time-velocity integral and an increase in A-wave and its time-velocity integral were detected with echocardiography. Moreover, RNA showed a reduced peak filling rate and an increased isovolumic relaxation time. When compared with normal values, an abnormal diastolic filling, defined as two independent echocardiography plus one RNA variable impairment, was found in 15 patients (57.6%) in group A and in only 4 patients (11.4%) in group B (P < 0.001). Our findings suggest an early involvement of diastolic function in patients with CAN.

Adolescent↗

Correlation between late potentials duration and QTc dispersion: Is there a causal relationship?

QTc interval dispersion (QTcd) analysis (difference between maximum and minimum QTc calculated from at least five of the standard 12 ECG leads) and signal-averaged electrocardiograms were performed on 23 patients referred to our coronary care unit because of acute myocardial infarction. Late potentials were considered positive if all three of the following criteria were satisfied: (1) total QRS duration (QRSd) > 114 ms; (2) duration of QRS under 40 muV (LAS 40) > 38 ms; (3) root mean square voltage of the last 40 ms of QRS (RMS 40) < 25 muV. Patients were divided into two groups according to the presence (group A, 9 patients) or absence of late potentials (group B, 14 patients). Group A patients showed a significantly higher QTcd (0.0652 +/- 0.0177 s vs. 0.0448 +/- 0.0201 s; P = 0.021) and a significantly longer mean QTcm (0.43117 +/- 0.01817 s vs. 0.40472 +/- 0.03013 s; P = 0.028) than group B patients. Among the three different parameters used to define the presence of late potentials, QTcd was significantly related to LAS 40 (r = 0.418, P = 0.047) and mean QT cm to QRSd (r = 0.497; P = 0.016). We also found a significant correlation between QTcd and mean QTcm (r = 0.426; P = 0.043). In conclusion, our data suggest that (1) the presence of late potentials is associated with a greater dishomogeneity of ventricular recovery time; (2) the longer the duration of late potentials, expressed by LAS 40, the greater the QTcd, suggesting that the dispersion of repolarization could be attributed to slowly conducting areas from which late potentials arise; (3) mean QTcm is not useful to identify these areas because it is more affected by total rather than by terminal QRS duration; (4) regional discrepancies of ventricular recovery time are connected with general repolarization duration.

Action Potentials↗

[The pharmacological treatment of supraventricular atrioventricular nodal reentry or accessory pathway reentry tachycardias: the usefulness of transesophageal electrophysiological study in the selection of therapy].

Transesophageal atrial pacing is a diagnostic and therapeutic tool in patients with supraventricular reciprocating tachycardia (SVRT). The aim of the present study was to evaluate the effectiveness of transesophageal atrial pacing in the selection of the chronic treatment of SVRT. Between June 1993 and March 1995 we have performed transesophageal atrial pacing in 44 patients affected by atrioventricular nodal reentry tachycardia (AVNRT: n = 28) or atrioventricular reentrant tachycardia (AVRT) using a concealed or manifest bypass tract (n = 16). After a basal (free drug state) transesophageal atrial pacing, we performed serial electropharmacological tests during chronic treatment with sotalol (160 mg/die), flecainide (200 mg/die) and propafenone (450 mg/die). At the end of these tests, the patients were finally discharged with the drug that allowed a more difficult induction or a wider cycle length, and that showed a better clinical tolerance. At the end of the electropharmacological tests 53.6% of the patients affected by AVNRT were discharged with sotalol, 17.8% with propafenone and 28.6% with flecainide. The follow-up of these 28 patients is 11.4 +/- 1.7 months. In the 79.2% of the patients the drug is still effective (absence of whatever episode of SVRT in the follow-up period). In the AVRT group, at the end of the electropharmacological tests, 25% of the patients were discharged with sotalol, 6.25% with propafenone, and 68.75% with flecainide. The follow-up of these 16 patients is 11.7 +/- 1.8 months. In the 78.6% of the patients the drug is still effective (absence of episode of SVRT in the follow-up period).

Adolescent↗

[An unusual case of ectopic atrial tachycardia: triggered activity as an arrhythmogenic mechanism].

We report a rare case of ectopic atrial tachycardia induced by ergometric stress test whose arrhythmogenic mechanism, after transesophageal electrophysiological study, seemed to be triggered activity. The patient was successfully treated with a beta-blocker (metoprolol), confirming the importance of autonomic modulation in the genesis of arrhythmias caused by afterdepolarizations.

Adrenergic beta-Antagonists↗

[Sotalol, propafenone, and flecainide: compared multiparametric analysis of ventricular repolarization in subjects without organic cardiopathy].

Antiarrhythmic drugs are known to affect depolarization and repolarization time in a different fashion. The aim of the present study was to compare the effects of sotalol, flecainide and propafenone on some common (mean QT and QTc, mean JT and JTc), or uncommon (QTc dispersion, T-peak to T-end interval-Tp-Te) electrocardiographic parameters in order to evaluate the effects of these antiarrhythmic drugs on repolarization time. QTc dispersion, defined as the difference between maximum and minimum QTc calculated from the standard 12 ECG leads, and the average Tp-Te interval, reflect regional variation in ventricular repolarization. We have analyzed retrospectively the standard 12-lead electrocardiograms of 28 patients (15 females and 13 males, age 36.11 +/- 16 years, range 11-67 years), recorded in the free-drug state and at the steady state after oral treatment with sotalol (160 mg/ die), flecainide (200 mg/die) and propafenone (450 mg/die). These drugs were prescribed, separately, for the treatment of patients with supraventricular tachycardia without underlying structural heart disease. Sotalol treatment prolongs ventricular repolarization times (QT, p = 0.0001; JT, p = 0.0001 and JTc, p = 0.0001) in an homogeneous fashion, as showed by the significant decrease in QTc dispersion (p = 0.026) and Tp-Te interval (p = 0.011). On the contrary, flecainide treatment is associated with an increase in QTc dispersion (p = 0.039) and Tp-Te interval (p = 0.0001), mean QT (p = 0.0001), QTc (p = 0.0001) and QRS (p = 0.0001), with no significant changes in JT and JTc (NS). Propafenone treatment does not affect repolarization time indexes, affecting only depolarization time as expressed by an increase in QRS (p = 0.046).

Adolescent↗

[The electrophysiological bases of aberrant intraventricular conduction during atrial fibrillation].

Twenty-four hours electrocardiogram from 4 patients with chronic atrial fibrillation and intraventricular aberrant conduction were analyzed. Aim of the study was to evaluate the reliability of the Ashman's and Akthar's rules in electrocardiographic differential diagnosis between aberrancy and ectopy. We computed parameters related to 10 RR interval preceding the aberrant conduction (AB+ Group), normal complex QRS (AB-Group) and ectopic QRS (E Group): coupling interval (CI), preceding CI cycle (PCL1), preceding PCL1 cycle (PCL2), the difference between PCL1 an PCL2 (delta PCL1), the difference between CI an PCL1 (delta CI), the mean value (RR10) and the standard deviation (RR10SD) of the 10 QRS complexes preceding the end of the sequence. Specificity of Akthar's rule was 48.7% (range 45-50%), sensibility was 90.1% (range 75-100%). PCL2, delta PCL1 and RR10DS were significantly different between AB+ and AB- Group but not between AB+, AB- and E Group. In this work Akthar's rule showed a better reliability than Ashman's rule but specificity was low (probably related to concealed conduction in atrio-ventricular node). RR10DS, but not RR10, were significantly higher in AB+ Group than AB- Group suggesting that acceleration of the cycle length can provoke CVA by increasing the difference between the refractory period of His bundle branches. Aberrant ventricular conduction cannot be determined by a mathematical rule. In the differential diagnosis of wide QRS during atrial fibrillation only morphological analysis of QRS and the study of coupling interval and compensatory pause are helpful.

Atrial Fibrillation↗

Delivery and distribution of aerosolized cyclosporine in lung allograft recipients.

The aim of the present study was to identify factors determining the delivery to and distribution of aerosolized cyclosporine A (CSA) in the lungs of patients with severe pulmonary allograft rejection. Five such patients inhaled a previously characterized radioaerosol consisting of 4 to 6 cc of CSA (50 mg/ml) in ethanol mixed with technetium-99m (99mTc) bound to human serum albumin, generated by an AeroTech II nebulizer. The total dose of CSA depositing in the lungs was determined with a previously described inspiratory/expiratory mass-balance filter technique. Regional distribution of drug within the lungs was measured using a gamma camera. In addition, the following physiologic parameters were measured: regional volume and ventilation using xenon-133 (133Xe) equilibrium and 133Xe washout, respectively, and regional perfusion using intravenous 99mTc macroaggregates. The relationships between these parameters and regional drug deposition were assessed using linear regression analysis. The lung dose ranged from 20 to 53 mg (0.097 to 0.175 mg CSA deposited per milligram placed in nebulizer). In recipients of single-lung allografts, preferential drug deposition occurred either in the allograft (two patients) or in the native lung (one patient). Marked nonuniformities in regional distribution were also apparent in two double-lung allograft recipients. There was a weak but statistically significant correlation between regional drug deposition and regional ventilation, as measured by 133Xe washout (r = -0.542, p = 0.014), suggesting that although regional ventilation is important, it is not the only factor determining regional deposition in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Assessment of dispersion++ of ventricular recovery in patients with chronic obstructive pulmonary disease].

Cardiac arrhythmias are common in patients with chronic obstructive pulmonary disease. Several factors may contribute to the development of arrhythmias in these patients including hypoxemia, hypercapnia, acid-base disturbances. The aim of the study was to assess QTc dispersion in patients with chronic obstructive pulmonary disease, who are at high risk of arrhythmias. Interlead QT variability as measured on the 12-lead electrocardiogram is not a technical artifact but probably reflects regional differences in ventricular repolarization. Increased dispersion of ventricular recovery time is believed to provide a substrate which supports serious ventricular arrhythmias. We showed that in patients with chronic obstructive pulmonary disease, free of underlying structural heart disease, the QTc dispersion is significant greater (p = 0.036) than in a control group, despite a similar value in mean QTc value. The data of the present study suggest that the determination of dispersion of repolarization times may be affected by metabolic changes occurring in patients with chronic obstructive pulmonary disease.

Adult↗

[Sex hormones, glycolipid metabolism, and atherogenesis].

The prevalence of coronary artery disease is lower in women than in men. Ovarian estrogen is believed to decrease the risk of coronary heart disease. Today, there is an increasing demand for estrogen replacement not only for amelioration of menopausal subjective symptoms but also for the prophylactic action of estrogen against osteoporosis in postmenopausal women. Is generally agreed that estrogen replacement therapy reduces cardiovascular morbidity and mortality in postmenopausal women. Estrogen replacement therapy may protect against coronary heart disease by altering plasma lipoprotein concentrations, by increasing HDL cholesterol and decreasing LDL cholesterol, and thereby inhibiting progression of coronary artery atherosclerosis. Oral contraceptive can induce deterioration in glucose tolerance that has consistently been associated with insulin excess and insulin resistance. This situation can increase the coronary heart disease risk. New findings suggest that there may be independent cardioprotective effects of estrogen, such a direct inhibitory influence on thrombosis, vasospasm or atherogenesis, inhibiting atherosclerotic plaque formation in arterial walls.

Arteriosclerosis↗