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Biomedical subjects

A Raviele

Publications and source records attributed to A Raviele.

At least 19 recordsLinked to original sources
PubMed1996

Implantable cardioverter-defibrillator (ICD) indications in 1996: have they changed?

The recent progress in the technology of the implantable cardioverter-defibrillator (ICD) and the excellent clinical results achieved with ICD treatment in the prevention of sudden death have facilitated the wide-spread acceptance and diffusion of this therapeutic modality. However, ICD implantation is a costly therapy and its use is still associated with some important unresolved issues. In particular, owing to the absence of randomized controlled clinical trials, it is not yet known whether ICD really reduces overall mortality. Thus, at the present time, it appears logical to exercise restraint in expanding the use of ICDs as first-choice therapy in patients with life-threatening ventricular arrhythmias. ICD treatment should be restricted to those well-defined categories of high-risk patients who are most likely to benefit from device implantation in terms of life prolongation. Basically, this means patients with hemodynamically poorly tolerated ventricular tachycardia or ventricular fibrillation that are not inducible at electrophysiologic study and those who do not respond to, or do not tolerate, drug therapy with amiodarone, sotalol, or beta blockers. Patients with idiopathic ventricular fibrillation also seem to be suitable candidates for ICD implantation. Other indications for ICD therapy are, as yet, more controversial and should be carefully evaluated on a case-by-case basis.

Death, Sudden, Cardiac↗
PubMed1995

Value of head-up tilt testing potentiated with sublingual nitroglycerin to assess the origin of unexplained syncope.

This study was undertaken to assess the value of sublingual nitroglycerin administration during upright tilt as a simple practical test for the diagnosis of vasovagal syncope. To this purpose, 235 patients with syncope of unknown origin and no evidence of organic heart disease (110 men, mean age 52 +/- 20 years) and 35 asymptomatic control subjects underwent head-up tilt testing with nitroglycerin challenge. Patients and subjects were tilted at 60 degrees for 45 + 20 minutes; the initial 45 minutes were without medication and the final 20 minutes after 300 micrograms of sublingual nitroglycerin. During the drug-free phase of the test, 59 patients (25%) and no controls had a positive response. After drug administration, a positive response (syncope in association with sudden hypotension and bradycardia) occurred in 60 patients (26%) and in 2 controls (6%), whereas an exaggerated or false-positive response (minor or different symptoms in association with slowly increasing hypotension alone) was observed in 33 patients (14%) and in 5 controls (14%). We conclude that the sublingual nitroglycerin head-up tilt test is a useful tool to unmask the vasovagal origin of unexplained syncope in patients without organic heart disease. The addition of nitroglycerin to upright tilt allows the positive rate of passive tilting to be doubled (51% vs 25%) while maintaining a high specificity (94% vs 100%).

Administration, Sublingual↗
PubMed1995

Italian multicenter clinical experience with endocardial defibrillation: acute and long-term results in 307 patients. The Italian Endotak Investigator Group.

This study presents the acute and long-term results of 307 patients (267 men, mean age 57.5 years, 205 suffering from coronary artery disease, mean left ventricular ejection fraction 33.3%) with malignant ventricular tachyarrhythmias who underwent attempted transvenous ICD implantation with the CPI Endotak lead system in 37 Italian centers. Transvenous ICD implantation was ultimately accomplished in 306 (99.7%) patients. These included 19 subjects with high (< 10 J below output energy of implanted device) defibrillation threshold (DFT) at implant. One hundred sixty-four patients (53%) were implanted with the endocardial lead alone, while 142 also received an SQ patch or SQ array. The mean DFT (not always step-down DFT) at implant was 16.9 +/- 5.7 joules; 15.3 +/- 5.2 joules with biphasic shock and 19.6 +/- 5.4 joules with monophasic shock; P < 0.0001. A significantly higher percentage of patients tested with a biphasic shock could be implanted with adequate safety margin and without an additional SQ patch or SQ array (98% and 81%, respectively). No perioperative deaths occurred. During the mean follow-up of 14.5 +/- 10.2 months, 140 patients (52%) received at least one appropriate shock. An inappropriate shock was observed in 26% of episodes. The 1- and 3-year actuarial incidence of sudden death was 2% and 4%, respectively, and that of total death was 10% and 20%, respectively. A pocket infection requiring ICD explantation occurred in 4 patients (1.4%) and an endocardial lead dislodgment in 11 patients (3.6%). Two patients (0.3%) showed a sensing pin disconnection and six patients (2.3%) had a lead insulation break. The results of this Italian multicenter trial indicate that the CPI Endotak lead system is a simple, safe, and reliable system for endocardial defibrillation. When compared to epicardial leads, it clearly reduces the perioperative mortality and morbidity, while maintaining a similar efficacy in preventing sudden death and terminating ventricular arrhythmias.

Actuarial Analysis↗
PubMed1994

Nitroglycerin infusion during upright tilt: a new test for the diagnosis of vasovagal syncope.

The aim of our present study was to assess the value of nitroglycerin infusion during upright posture as a new provocative test for diagnosis of vasovagal syncope. To this purpose 40 patients with unexplained syncope (17 men and 23 women, mean age 47 years) and 25 asymptomatic control subjects with negative baseline head-up tilt underwent two other tilting tests, one during nitroglycerin infusion and one during isoproterenol infusion. The protocol of the nitroglycerin test consisted of a maximum of five successive stages of 5 minutes in the supine position plus 10 minutes 80-degree upright tilt at progressively increasing infusion rates (increments of 0.86 microgram/kg/hr every stage). During the nitroglycerin test a positive response (syncope in association with sudden hypotension and bradycardia) occurred in 21 (53%) patients with unexplained syncope, an exaggerated response (minor symptoms in association with slowly increasing hypotension alone) occurred in 10 (25%), a negative response in 9 (22%), and drug intolerance in 0. During the isoproterenol test these percentages were 25%, 25%, 32%, and 18%, respectively. Only 2 (8%) control subjects had a positive response to nitroglycerin test and 2 (8%) to isoproterenol test. Thus the nitroglycerin test seems to be a useful alternative tool for diagnosis of vasovagal syncope; it is equally specific but more sensitive and feasible than the isoproterenol test.

Adult↗
PubMed1993

Role of autonomic reflexes in syncope associated with paroxysmal atrial fibrillation.

OBJECTIVES: The purpose of this study was to evaluate the role of autonomic reflexes in the genesis of syncope associated with the onset of paroxysmal atrial fibrillation. BACKGROUND: Syncope associated with paroxysmal atrial fibrillation has been interpreted as an ominous finding predictive of rapid ventricular rates. However, various mechanisms may be involved when heart rate is not particularly high. METHODS: Forty patients (age 60 +/- 14 years, 20 men, 20 women) with syncope and atrial fibrillation were compared with atrial fibrillation without syncope. Carotid sinus massage and head-up tilt testing (at 60 degrees for 60 min at baseline and during isoproterenol infusion) were performed during sinus rhythm. A positive response was defined as the induction of syncope. Atrial fibrillation was also induced on a tilt table at 60 degrees by means of short bursts of atrial pacing. RESULTS: Results of carotid sinus massage were positive in 15 (37%) of 40 patients but in no control subjects (p = 0.002). Head-up tilt test findings were positive in 25 (66%) of 38 patients and in 2 (12%) of 16 control subjects (p = 0.0004). The induction of atrial fibrillation in the upright position elicited syncope in 16 (42%) of 38 patients but in none of 16 control subjects (p = 0.001). At the beginning of atrial fibrillation, systolic blood pressure was lower in patients than in control subjects (88 +/- 32 vs. 127 +/- 32 mm Hg), whereas mean heart rate was similar (142 +/- 35 vs. 134 +/- 25 beats/min). The correlation between heart rate and systolic blood pressure was weak (r = 0.35), and in five patients syncope occurred at a heart rate < or = 130 beats/min. At the time of syncope, heart rate decreased (-12 +/- 21 beats/min) in patients with induced syncope, whereas it remained unchanged in patients without induced syncope (+1 +/- 17 beats/min, p = 0.04) or slightly increased in control subjects (+9 +/- 21 beats/min, p = 0.009). CONCLUSIONS: Patients with syncope associated with paroxysmal atrial fibrillation are predisposed to an abnormal neural response during both sinus rhythm and arrhythmia. In some patients the onset of atrial fibrillation triggers vasovagal syncope.

Aged↗
PubMed1991

Successful catheter ablation by radiofrequency energy of posteroseptal accessory pathway in a patient with drug refractory Wolff-Parkinson-White syndrome.

A 45-year-old patient with the Wolff-Parkinson-White syndrome suffering from recurrent intractable reciprocating atrioventricular tachycardia (RAVT) is reported. He used amiodarone, sotalol, quinidine, propafenone and flecainide unsuccessfully. An electrophysiological study (EPS) performed with four catheters localized the site of the anomalous pathway in the ostium of the coronary sinus. In this region we could also record a Kent potential. In the ostium of the coronary sinus, radiofrequency energy was repeatedly applied until the conduction over the accessory pathway was abolished both in the anterograde and the retrograde direction. The Kent deflection detectable before ablation, could not be detected after it. During follow-up (1 month) the patient remained asymptomatic and the control EPS showed no evidence of pre-excitation, either anterogradely or retrogradely.

Anti-Arrhythmia Agents↗
PubMed1991

[The endocavitary and transesophageal electrophysiological findings in idiopathic atrial fibrillation].

BACKGROUND: We studied 105 patients (pts) in order to help clarify the pathogenetic mechanisms of idiopathic atrial fibrillation (AF). Eighty of these pts (Group I) had experienced paroxysmal AF, and 25 were normal control subjects (Group II). Twenty-two pts out of Group I had idiopathic paroxysmal AF (Group IA), while the remaining 58 (Group IB) presented with a heart disease or a WPW pattern. METHODS: All pts underwent endocavitary (EEPS) (69) or transesophageal (TEPS) (36) electrophysiologic study. In all pts the inducibility of a sustained AF (greater than 1 min) was tested by aggressive stimulation protocols including high frequency atrial bursts. RESULTS: In Group I a sustained AF was induced in 82% of cases vs 4% of Group II cases (p less than 0.001). In Group I there was no difference between pts with or without idiopathic AF (IA 73% vs IB 86%, NS). In two pts with idiopathic AF a concealed Kent bundle was identified and a reciprocating atrioventricular tachycardia was induced, which in one case spontaneously degenerated into AF. Four athletes with idiopathic AF were studied before and after autonomic blockade. AF was induced in all during the basal state, lasting several hours, and after autonomic blockade in 3 pts, lasting again for several hours. In 1 patient (pt) the arrhythmia spontaneously resolved within 50 sec. CONCLUSIONS: 1) The induction of a sustained AF by EEPS or TEPS is a pathologic phenomenon which is frequently observed in pts with clinical episodes of paroxysmal AF, while it is very rare in normal control subjects. 2) Pts with idiopathic AF have an electrophysiologic behaviour similar to pts with non-idiopathic AF. This fact suggests that among the former, most cases probably have a concealed atrial anomaly. In some cases this atrial anomaly can be related to the existence of a Kent bundle. 3) In athletes with paroxysmal AF the inducibility of a sustained AF both in the basal state and after autonomic blockade suggests that the vagal prevalence typical of such subjects probably plays a secondary role.

Atrial Fibrillation↗
PubMed1991

[Supraventricular paroxysmal reentry tachycardia. Empirical and guided therapy].

The empirical therapy of reentrant supraventricular tachycardias (A-V and junctional tachycardia) is based on a preliminary diagnosis through standard ECG to evaluate, whenever possible, the relationship between P wave and QRS. In order to distinguish atrial tachycardias from other types, we must employ vagal manoeuvres or drugs. Often we use methods of recording and stimulation such as Holter monitoring and transesophageal technique which can provide useful information about the electrophysiological mechanisms and therefore can better guide our choice of drugs. The decision of undertaking pharmacologic treatment takes into account frequency, duration and tolerability of the crises and the patient's compliance. The most commonly used drugs are verapamil, diltiazem, propafenone, flecainide, sotalol and amiodarone. The percentage of success at 1 year ranges from 30 to 60%. Particularly in the Wolff-Parkinson-White (WPW) therapy must follow an accurate evaluation of the electrophysiological pattern through effort test, drugs test, transesophageal (ETS) or endocavitary (EPS) electrophysiological study. Indeed therapy aims not only at reducing arrhythmic relapses, but also preventing the potential risk of either death or severe damage. The useful drugs must have the property of acting at the same time upon at least one branch of the A-V circuit, on the atrium reducing its vulnerability and finally modifying the conductive anterograde capacity of the Kent bundle. They are quinidine, procainamide, propafenone (group I) sotalol and amiodarone (group III). The limitations of the empirical therapy are a high percentage of relapses and the difficulty in foreseeing the pro-arrhythmic effects. The guided by serial electrophysiologic testing implies artificial induction of spontaneous arrhythmia by repeating the test after acute or chronic assumption of drugs. Is this way it can be evaluated the efficacy as well as the tolerability of an antiarrhythmic drug which later will be taken for chronic prophylaxis. The percentage of inducibility of clinical arrhythmias is next to 100% both for EPS and TES. The number of patients for whom we can find an effective pharmacologic regimen through acute testing ranges from 30 to 100%, but is influenced by several factors such as aggressiveness of therapeutic protocol and type and dosage of drugs. The predictive value is high as it approaches 100% for a positive acute test. The elective indications for serial electrophysiologic study are: failure of empirical therapy; disabling and very frequent arrhythmias; arrhythmias provoking major disturbances (lipothymia, syncope, hypotension, shock); symptomatic WPW.

Anti-Arrhythmia Agents↗
PubMed1991

[Treatment of malignant ventricular tachyarrhythmia with amiodarone: comparison of empirical administration and administration guided by Holter or ventricular stimulation. Results of the parallel test].

To assess the most appropriate method of administering amiodarone and predicting its efficacy (empiric vs guided by Holter or by ventricular stimulation), 19 patients with sustained ventricular tachycardia or ventricular fibrillation underwent a "parallel study". Fifteen patients were men and 4 women, with a mean age of 65 years. A coronary artery disease with previous myocardial infarction was present in 15 patients, dilated cardiomyopathy in 3 and arrhythmogenic right ventricular dysplasia in 1 (mean left ventricular ejection fraction = 35%). All 19 patients had, as inclusion criteria, 1) frequent (greater than or equal to 30/hour) and/or repetitive (greater than or equal to 10/24 hours) ventricular premature beats during 24-hour Holter monitoring and 2) inducible sustained (greater than 30/sec) ventricular arrhythmias during programmed ventricular stimulation (1-3 extrastimuli from 2 right ventricular sites). Amiodarone was given at an initial dosage of 15 mg/kg/day for 2 weeks and then at a dosage of 5 mg/kg/day. After 15 days 24-hour Holter monitoring and programmed ventricular stimulation were repeated. The data of these tests, however, were not used to guide the therapy that remained empiric, but served only to assess retrospectively the predictive value of Holter monitoring and ventricular stimulation. The following main results were obtained: The mean duration of follow-up was 25 +/- 13 months. During this period 6 patients (32%) died, 3 from sudden and 3 from non-sudden cardiac death. Two other patients had recurrence of sustained ventricular arrhythmias. After 15 days of therapy amiodarone was effective at Holter monitoring in 15 patients (79%) and not effective in 4 (21%). Two of the 15 patients considered responders died suddenly during the follow-up and 2 had arrhythmic recurrence, vs 1 of the 4 non-responder patients who died suddenly (negative predictive value of Holter monitoring: 73%; positive predictive value: 25%; predictive accuracy: 63%). After 15 days of therapy amiodarone was effective at ventricular stimulation in 10 patients (53%) and not effective in 9 (47%). None of the 10 patients considered responders had arrhythmic events during the follow-up, vs 5 of the 9 non-responders, 3 of whom died suddenly and 2 of whom had arrhythmic recurrences (negative predictive value of ventricular stimulation: 100%; positive predictive value: 56%; predictive accuracy: 79%). Only 1 patient discontinued amiodarone after 25 months of follow-up because of development of an important blue-grey skin discoloration.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Usefulness of head-up tilt test in evaluating patients with syncope of unknown origin and negative electrophysiologic study.

The vasovagal nature of syncope, which remained unexplained despite full clinical and electrophysiologic investigation, was evaluated by means of 60 degrees head-up tilt test for 60 minutes. Thirty patients (17 men and 13 women, mean age 65 years, 19 with and 11 without organic heart disease) with 1 to 28 (mean 5) episodes of syncope of unknown origin were studied. Head-up tilt test was considered positive if syncope developed in association with hypotension, bradycardia, or both. During baseline head-up tilt 15 patients (50%) had a positive response. Ten patients had a vasodepressor response (marked hypotension without marked bradycardia) and 5 had a mixed response (marked hypotension with marked bradycardia). None of 8 control subjects became symptomatic during the test. Baseline head-up tilt test was positively reproducible in 10 of 14 patients (71%). Nine of these 10 patients underwent serial head-up tilt tests after drug administration to determine the pathogenesis of vasovagal syncope. Atropine prevented tilt-induced syncope in 3 of 8 patients (37.5%), propranolol in 2 of 8 (25%) and etilephrine in 7 of 7 (100%). Seven patients received long-term drug treatment with drugs selected on the basis of acute drug testing. One responder to atropine received transdermal scopolamine and 6 received etilephrine. None of these 7 patients had syncopal recurrences or death during a mean follow-up of 12 months. Head-up tilt is a very sensitive and highly specific test to unmask susceptibility to vasovagal reaction in patients with syncope of unknown origin. Withdrawal of alpha-sympathetic stimulation is a principal mechanism responsible for vasodilation and syncope during head-up tilt.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Agonists↗