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Biomedical subjects

F Gaita

Publications and source records attributed to F Gaita.

At least 19 recordsLinked to original sources
PubMed1992

Washout of long-term treatment with flecainide and propafenone in patients with complex ventricular arrhythmias and cardiac disease. Antiarrhythmic Drug Evaluation Group.

To assess the spontaneous variability of ventricular arrhythmias after withdrawal of apparently successful antiarrhythmic therapy, we enrolled in a washout protocol 40 patients who had completed a randomized controlled 2-year study of antiarrhythmic drugs (the Antiarrhythmic Drug Evaluation Group [ADEG] study). All of them had heart disease and were first seen with high-grade ventricular arrhythmias (Lown class 4a and 4b) at enrollment. After 2 years all of them had responded to propafenone or flecainide; patients who completed the study on a regimen of amiodarone were not considered for the washout study. A total of 27 patients discontinued flecainide and 13 propafenone. Seven days after withdrawal they underwent 24- or 48-hour ECG testing and were classified as true responders (TR) if the arrhythmias were present at the same level as 2 years previously and false responders (FR) if they were below the ADEG responsiveness level. TR patients had a third 24-hour ECG 7 days later, after rechallenge with the same treatment, and FR patients had a third ECG without drugs. Adherence to the protocol was ascertained by measuring drug plasma concentrations at every 24-hour ECG recording. No differences were found in distribution of heart disease and grade of ventricular arrhythmias between patients in the washout study and the remaining group of the ADEG trial. Twenty-four of 40 patients (60%) were true responders. In 4 of the 17 patients who had a third 24 hour ECG, the responsiveness to the same drug was not confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1992

Elimination of atrioventricular nodal reentrant tachycardia using discrete slow potentials to guide application of radiofrequency energy.

BACKGROUND: Ablation of the slow pathway has been performed to eliminate atrioventricular (AV) nodal reentrant tachycardia (AVNRT) either by a surgical approach or by using radiofrequency catheter technique guided by retrograde slow pathway activation mapping. From previous experience of midseptal and posteroseptal mapping, we were aware of the existence of peculiar slow potentials in most humans. Postulating their role in AVNRT, we studied these potentials and the effects of radiofrequency energy. METHODS AND RESULTS: Sixty-four patients (mean age, 48 +/- 19 years) with the usual form of AVNRT were studied. Slow, low-amplitude potentials were recorded when using the anterograde AV conducting system. Slow potentials occupied all (giving a continuum of electrograms) or some of the time between the atrial and ventricular electrograms. Their most specific patterns were their progressive response to increasing atrial rates, which resulted in a dramatic decline in amplitude and slope, a corresponding increase in duration, and a separation from preceding atrial potentials until the disappearance of any consistent activity. Slow potentials were recorded along a vertical band at the mid or posterior part of the septum near the tricuspid annulus. Radiofrequency energy applied at the slow potential site resulted in interruption of induced tachycardia within a few seconds and rendered tachycardia noninducible in all patients. A median of two impulses was delivered to each patient. In 69% of patients, postablation atrial stimulation cannot achieve a long atrial-His interval, which previously was critical for tachycardia induction or maintenance. No patient had AVNRT over a follow-up period of 1-16 months, and all had preserved AV conduction. In all except two patients, the PR interval was unchanged. In 47 patients, long-term electrophysiological studies confirmed the efficacy of ablation and the nonreversibility of results by isoproterenol; however, echo beats remained inducible in 40% of patients. CONCLUSIONS: An area showing slow potentials is present at the perinodal region in humans. In patients with AVNRT, application of radiofrequency energy renders tachycardia noninducible through the preferential modification of the anterograde slow pathway. With present clinical methods, the exact origin and significance of these physiological potentials cannot be specified.

Cardiac Pacing, Artificial↗
PubMed1992

Radiofrequency catheter ablation of left lateral accessory pathways via the coronary sinus.

BACKGROUND: The purpose of this study was to describe a new technique for catheter ablation of left lateral accessory pathways (APs) by radiofrequency energy applied at the epicardium through the coronary sinus wall using a unipolar configuration. METHODS AND RESULTS: In an overall group of 212 patients with left lateral APs, multiple endocardial ablation attempts of the AP were unsuccessful in eight patients. The mean +/- SD cumulative duration of previous attempts was 12 +/- 9 hours, using DC shocks and/or radiofrequency energy applied both at the atrial and/or ventricular AP insertions. Epicardial AP insertion was determined by bipolar and unipolar unfiltered distal electrograms by scanning the coronary sinus with a steerable 6F or 7F catheter with a 4-mm distal electrode. The local atrial to ventricular electrogram amplitude ratio was 0.3-1.6. At the ablation site, the catheter tip was slightly deflected toward the annulus to increase both the ventricular component of electrograms and contact with the epicardium. In four patients, epicardial electrogram timings were earlier than endocardial ones. The AP was ablated in seven of the eight patients with 20-30 W applied for 10-60 seconds. No complications occurred except a marked nonspecific pain during radiofrequency energy application; however, the catheter remained adherent to the coronary sinus wall, and its withdrawal was performed during a new radiofrequency application to decrease the risk of coronary sinus rupture. After ablation, echocardiograms, coronary artery angiograms, and levophase coronary sinus angiograms showed no abnormality in all patients except two who had a probable mural thrombus in the coronary sinus. AP conduction remained abolished for 1-10 months of follow-up in seven patients. CONCLUSIONS: Radiofrequency catheter ablation of left lateral APs can be achieved effectively and relatively safely via the mid or distal coronary sinus when endocardial approaches are unsuccessful.

Catheter Ablation↗
PubMed1992

Wolff-Parkinson-White syndrome. Identification and management.

Patients with Wolff-Parkinson-White (WPW) pattern of ventricular pre-excitation may develop paroxysmal re-entrant tachyarrhythmias through the Kent bundle and, less commonly, atrial fibrillation. WPW patients are at risk of sudden death when a rapid ventricular response occurs during atrial fibrillation due to conduction through the accessory pathway. Conduction properties of the accessory pathway and atrial vulnerability, which is the propensity to develop atrial fibrillation, are important parameters for evaluation in these patients. The former can be assessed by means of noninvasive tests, such as stress and pharmacological tests, and with electrophysiological study; the latter only by electrophysiological study. There is no indication for treatment of asymptomatic patients. Antiarrhythmic prophylaxis is required in patients with previous episodes of atrial fibrillation with rapid ventricular response, in patients with paroxysmal re-entrant tachycardias and rapid conduction through the accessory pathway, and in patients with frequent episodes of re-entrant tachycardias of long duration. Vaughan-Williams class IC anti-arrhythmic drugs (propafenone, flecainide) are the first choice for drugs in patients with rapid anterograde conduction through the accessory pathway due to their high efficacy and low incidence of adverse effects, while beta-blockers (atenolol, nadolol) are indicated for patients with re-entrant tachycardias and low conduction capacity through the bypass tract. When pharmacological therapy is ineffective, surgical or catheter ablation of the accessory pathway may be considered.

Arrhythmias, Cardiac↗
PubMed1992

Catheter ablation of accessory pathways in patients with Wolff-Parkinson-White syndrome.

PATIENTS: Fifty-two patients with Wolff-Parkinson-White syndrome underwent transcatheter ablation. All patients were symptomatic. Eighteen had documented episodes of atrial fibrillation, 14 of which also had reentrant tachycardias; the remaining 34 had only episodes of reentrant tachycardias. Forty-nine patients had both anterograde and retrograde conduction through the accessory pathway; 3 had retrograde conduction alone; 2 patients had 2 accessory pathways and 1 had 3. All patients were resistant or intolerant to at least 2 antiarrhythmic drugs. METHODS: All patients were treated with radiofrequency current. Ablation was considered successful if the anterograde and retrograde conduction were completely abolished. Ablation was considered unsuccessful if ablation of only 1 pathway in patients with 2 or more accessory pathways and/or modification of the accessory pathway conduction without interruption was achieved. RESULTS: Accessory pathway ablation was successfully performed in 46 out of 52 patients (88%). Fifty out of 56 accessory pathways were effectively ablated (89%). Thirty-eight required a single session of ablation and 8 additional patients were successfully ablated during a second session. The number of radiofrequency current applications ranged from 2 to 13 (mean 4.1 +/- 2.5). The mean duration of the sessions was 4.30 +/- 1.50 hours (range 2.30 to 9). The mean radiation exposure for session was 55 +/- 25 minutes (range 20 minutes to 2.30 hours). Complications were observed in 2 out of 52 patients. One patient had a transient II degree type 1 atrioventricular block; another patient with severe arterial hypertension had a mild hemorrhagic stroke with complete neurological remission. FOLLOW-UP. Forty-five out of the 46 patients in whom ablation was successful were asymptomatic for arrhythmias during a mean follow-up of 8 months (range 4 to 16), without antiarrhythmic treatment, and without reappearance of preexcitation. One patient showed reappearance of preexcitation at electrocardiogram one month after the ablation, followed by an episode of reentrant tachycardia; this patient underwent a second successful ablation session. CONCLUSIONS: Our results show that ablation techniques have high success rates with no serious complications.

Adolescent↗
PubMed1992

[Propafenone versus hydroquinidine in long-term pharmacological prophylaxis of atrial fibrillation].

New antiarrhythmic class 1C agents have been proposed in the last few years in an attempt to suppress paroxysmal atrial fibrillation at long-term, as the most commonly used class 1A agents such as quinidine gave highly variable results as regards both side-effects and efficacy. The aim of this randomized prospective study is to evaluate the efficacy and safety of oral propafenone at long term in preventing paroxysmal atrial fibrillation and to compare the results with those obtained using agents such as quinidine. Two hundred patients with recurrent episodes of symptomatic atrial fibrillation were enrolled for this study with entry criteria based upon a history of more than 3 crises in the previous 6 months, with electrocardiographic (standard electrocardiogram or dynamic registration) documentation. According to a randomized selection either propafenone at 300 mg twice daily or hydroquinidine retard 250 mg twice daily were administered to the patients; clinical check-up was carried out every 3 months or if clinical course worsened. The dosages were increased if proved to be inadequate at check-up (i.e. recurrence of atrial fibrillation) up to 300 mg 3 times daily for propafenone and 500 mg twice daily for hydroquinidine. The efficacy at the 3rd month was 71% for propafenone and 60% for hydroquinidine, at the 6th month 60% for propafenone and 56% for hydroquinidine; this trend lowered progressively as the follow-up continued, to 48% for propafenone and 42% for hydroquinidine (NS). More than 70% of the responder patients assumed 600 mg twice for propafenone or 250 twice for hydroquinidine. Propafenone had a percentage of 10% side-effects and hydroquinidine 24% (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Nonpharmacological therapy of supraventricular arrhythmia].

Between 1985 and 1990, 1242 patients with supraventricular arrhythmias were followed-up at our Institution. Six hundred and twenty patients had atrial fibrillation or flutter; 7 of them (1%) underwent modulation of atrioventricular conduction. Four hundred and twenty-eight patients had ventricular preexcitation; in 23 (5%) surgical or transcatheter ablation of an accessory pathway were performed. Atrioventricular node reentrant tachycardias were diagnosed in 111 patients; 8 patients (7%) underwent antitachycardia pacemaker implantation. Surgical and catheter ablative techniques eliminate the substrate of the tachycardia; death and complete A-V block (paraseptal pathways) are at this moment rarely reported. Antitachycardia pacemakers do not offer a definitive therapy. For their safeness and effectiveness they are still indicated in patients with A-V node reentrant tachycardias, until technological development will reduce the risks of ablative techniques.

Arrhythmias, Cardiac↗
PubMed1990

Relation between spontaneous atrial fibrillation and atrial vulnerability in patients with Wolff-Parkinson-White pattern.

An intracavitary electrophysiological study was carried out on 103 patients with Wolff-Parkinson-White (WPW), 23 symptomatic patients had documented episodes of atrial fibrillation, 54 symptomatic patients had atrioventricular reentrant tachycardias, and 26 asymptomatic. Patients were examined for the relation between spontaneous atrial fibrillation and atrial vulnerability, defined as the possibility to induce sustained (greater than 1 minute) episodes of atrial fibrillation with a stimulation protocol excluding atrial bursts. Atrail fibrillation induction was attempted by single and double atrial extrastimuli during pacing at two different cycle lengths and incremental atrial pacing. Sustained atrail fibrillation was induced in 65% of the patients with spontaneous atrial fibrillation, and in 13% of the symptomatic patients with documented episodes of atrioventricular reentrant tachycardias and in 15% of the asymptomatic patients (P less than 0.0005). Atrial vulnerability was higher in patients with spontaneous atrial fibrillation than in patients without this arrhythmia. No significant difference was observed between symptomatic without atrial fibrillation and asymptomatic patients.

Adult↗
PubMed1990

[Induction of atrial tachyarrhythmia in patients with Wolff-Parkinson-White syndrome with and without spontaneous atrial fibrillation].

The purpose of this study was to examine the relation between spontaneous atrial fibrillation and the induction of atrial tachyarrhythmias during electrophysiologic study in patients with Wolff-Parkinson-White, with and without atrial fibrillation. Intracavitary electrophysiologic study was performed on 115 patients, 27 with spontaneous atrial fibrillation (group 1), 57 symptomatic due to AV re-entrant tachycardias, without spontaneous atrial fibrillation (group 2) and 31 asymptomatic (group 3). Induction of atrial fibrillation was attempted by using single and double atrial extrastimuli during atrial pacing at 2 different cycle lengths and by incremental atrial pacing (protocol A). When atrial fibrillation was not obtained, atrial bursts were added (protocol B). Atrial fibrillation or flutter were induced in 81% of group 1.54% of group 2 and 55% of group 3 patients (p less than 0.05), using protocol A. They were induced in 100, 75 and 71%, respectively (p = 0.01), with protocol B. Considering only sustained (greater than 1 minute) episodes, atrial fibrillation or flutter were induced in the three groups with protocol A in 74, 33 and 32% of the patients, respectively (p less than 0.001). The difference in the three groups was even greater when atrial fibrillation was considered separately from atrial flutter. The reason for this was that atrial fibrillation was induced in two thirds of group 1 patients, while only about 15% of patients without spontaneous atrial fibrillation had this arrhythmia induced. Our results suggest that the induction of sustained atrial fibrillation is a useful parameter to separate Wolff-Parkinson-White patients with from those without spontaneous atrial fibrillation. Due to the low specificity of the analysis of the shortest R-R interval during induced atrial fibrillation for the identification of the patients at risk of sudden death, the induction of sustained atrial fibrillation could be proposed as an additional parameter. This would improve the specificity of electrophysiologic study.

Adult↗
PubMed1989

Stress and pharmacologic tests as methods to identify patients with Wolff-Parkinson-White syndrome at risk of sudden death.

Noninvasive stress and pharmacologic tests with procainamide and propafenone were studied as methods to identify patients with Wolff-Parkinson-White syndrome (WPW) who would otherwise be judged at risk of sudden death on the basis of electrophysiologic criteria: the shortest RR interval during induced atrial fibrillation less than or equal to 250 ms or accessory pathway anterograde effective refractory period less than or equal to 250 ms. Sixty-five patients were studied. Twenty-four patients fulfilled the electrophysiologic risk criteria (group A) and 41 patients fulfilled none of these criteria (group B). Persistence of preexcitation during stress test showed a sensitivity of 96% and a specificity of 17% to identify group A patients; its positive predictive value was 40% and negative predictive value 88%. With both procainamide and propafenone tests persistence of preexcitation identified group A patients with a sensitivity of 96% and a specificity of 51%; their positive and negative predictive value were, respectively, 53 and 95%. Stress and pharmacologic tests have good sensitivity and negative predictive value, but low specificity and positive predictive value.

Adolescent↗
PubMed1989

Right ventricular dysplasia: radioisotopic angiography.

To evaluate if regional wall motion (RWM) abnormalities detected at rest in patients with high presumption of right ventricular dysplasia (RVD) are confirmed by stress test and could be considered of diagnostic value in the clinical setting of the disease, 12 patients underwent first-pass radionuclide angiography (RA) at rest and during exercise. The mean global right ventricular ejection fraction (EF) was 29.83 +/- 7.91 at rest; during exercise, we found a non-significant increase (32.16 +/- 9.8, P greater than 0.05). Six segments with systo-diastolic dyskinesis, three segments with diastolic dyskinesis, and 10 segments with akinesis at rest confirmed the same degrees of dysfunction during exercise. Eight of the 15 hypokinetic segments at rest showed normal function during exercise; the remaining seven confirmed the same degree of dysfunction during exercise. We conclude that various degrees of RWM abnormalities are found in all patients with RVD; hypokinetic dysfunction has to be confirmed by exercise. RWM abnormalities are not specific for RVD, and clinical and electrophysiological data should be combined to obtain as much evidence as possible for diagnosis.

Adolescent↗
PubMed1989

[Long-term variability in unsustained ventricular arrhythmias: pharmacologic and pro-arrhythmic effect].

A 72% reduction in the number of premature ventricular complexes, a 75 and 65% reduction in pairs and repetitive forms, respectively, are commonly accepted criteria for the evaluation of the efficacy of short-term antiarrhythmic treatment. On the other hand, a three-to-ten fold increase in the frequency of premature ventricular complexes is considered as a proarrhythmic effect. The aim of this paper is to verify if these criteria can still be applied on a long-term basis. Twenty-eight subjects without a demonstrable underlying organic heart disease and 21 patients with stable chronic ischaemic heart disease were studied. All patients showed more than 30 premature ventricular complexes per hour during ambulatory electrocardiogram monitoring. The spontaneous long term variability of ventricular arrhythmias was evaluated by comparing the first of three consecutive 24-hour ambulatory ECGs at the beginning of the study with a 24-hour ECG monitoring at the end of a 24-month follow-up period. According to the previous criteria about 50% of patients showed a spontaneous reduction in the number of premature ventricular complexes (greater than 72%) mimicking a therapeutic effect if any drug had been given. The increase in ventricular arrhythmias mimicked a proarrhythmic effect in almost 10% of patients. This trend is substantially the same both in subjects without organic heart disease and in patients with chronic coronary artery disease. The results of this study demonstrate that the initially established criteria used to judge the efficacy or the proarrhythmic effect of a given drug cannot be relied upon on a long-term basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Torsade de pointes during an atropine sulfate test in a patient with congenital long QT syndrome].

After a brief revision about the long QT syndrome, we report the case of a 52 year old man admitted to hospital for a syncopal attack. His electrocardiogram was considered normal: sinus bradycardia and U waves were recorded. The echocardiogram revealed anterior mitral leaflet redundancy and possible tricuspid prolapse. During the atropine test, after a normal increment of sinus frequency, 2 runs of self-limited torsade de pointes appeared. The electrocardiogram showed lesion wave at first, and then prolonged QT. During the intracavitary study, premature ventricular stimulation caused torsade de pointes. After propranolol iv it was no more possible to induce major ventricular arrhythmias anymore. Coronarography was normal. Nadolol therapy was begun. On 6 months follow-up the patient is asymptomatic.

Arrhythmias, Cardiac↗
PubMed1989

[Angiographic findings in arrhythmogenic dysplasia of the right ventricle].

Arrhythmogenic right ventricular dysplasia is characterized by fibrous and adipose replacement of the right ventricular myocardium and recurrent ventricular arrhythmias of left bundle branch block morphologic pattern. Sometimes the diagnosis is difficult because not all the clinical and instrumental findings are present and the separation between arrhythmogenic right ventricular dysplasia and other right ventricular cardiopathies is uncertain. In such cases the angiographic appearance of the right ventricle has been considered the "gold standard". To assess the diagnostic value of right ventricular morphology in identifying arrhythmogenic right ventricular dysplasia, we compared the angiographic findings of 8 patients with arrhythmogenic right ventricular dysplasia, 10 with biventricular dilated cardiomyopathy and 10 with Ebstein's anomaly. The following aspects were considered: deep fissuring of the anterior or inferior wall, outflow tract enlargement, contrast persistence in the right ventricle during the levophase, regional wall motion abnormalities including aneurysmal formations and tricuspid regurgitation. Aneurysmal formations of the right ventricle were found only in arrhythmogenic right ventricular dysplasia whereas the other angiographic findings were common to all the above mentioned diseases. Right ventricular angiography is an important adjunct to the clinical and instrumental diagnosis of arrhythmogenic right ventricular dysplasia, but most of its angiographic features are common to other diseases which cause right ventricular dilatation.

Adult↗
PubMed1988

[Characteristics and prognosis of ventricular arrhythmia in arrhythmogenic right ventricular dysplasia].

The authors report their findings in 47 cases of ventricular arrhythmias due to arrhythmogenic dysplasia. The 47 patients were selected on the presence of ventricular tachycardia or fibrillation associated with dysplasia affecting selectively (44/47) or predominantly (3/47) the right ventricle at angiography. In this series males were predominant (38/47, 81 p. 100), familial incidence was high (13/47, 28 p. 100) and ECG abnormalities were constant. Most of the dysrhythmias (40/47) consisted of sustained ventricular tachycardia (VT) with left bundle branch block pattern (96 p. 100), occurring at the rate of 1.6 per patient on average and seldom with extreme axial deviation, as seen in post-infarction VT or VT associated with cardiomyopathy. The QRS complex was slightly prolonged (151 +/- 28 ms) and of high amplitude (2.5 +/- 1 mV on a VR, a VL and a VF leads), these values being intermediate between those of mild VT bursts and those of post-infarction or cardiomyopathy-related VT. The tachycardia was easily tippered by EP study, Intercritical Holter recordings showed frequent ventricular extrasystoles in the vast majority of cases; these were usually polymorphous and grouped into short bursts in one-half of the patients. On an 8.3 +/- 7 years' follow-up starting with the first attack of VT, it was found that only during the initial phase the spontaneous onset of VT was mediated by the adrenergic system (triggered by sports). Only 3 patients died during the follow-up period: one of ventricular fibrillation, 2 of right heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[2 cases of arrhythmogenic dysplasia of the right ventricle of familial occurrence].

Cases of familial arrhythmogenic right ventricular dysplasia (ARVD) have been reported by many authors, and a genetic mechanism of transmission has been hypothesized. Both autosomal dominant and autosomal recessive mechanism of inheritance were suggest. We present a father and a daughter affected by arrhythmogenic right ventricular dysplasia, belonging to a family with many cases of sudden death. Both of them presented with an episode of ventricular tachycardia with left bundle branch block. The clinical diagnosis was made according to electrocardiographic, echocardiographic, angionuclear and hemodynamic criteria of ARVD. The familia analysis suggest an autosomal dominant mechanism of transmission.

Adolescent↗
PubMed1987

[Electrophysiologic study in supine and upright positions in patients with Wolff-Parkinson-White syndrome].

It is well known that in patients with Wolff-Parkinson-White (W.P.W.) adrenergic activity stimulation induced by exercise or isoproterenol I.V. infusion shortens the anterograde effective refractory period (E.R.P.) of the accessory pathway. Our purpose was to evaluate whether the upright position produces similar changes on the electrophysiologic properties of the accessory pathway and influences reciprocating tachycardias induction. In 18 patients, with W.P.W. syndrome, who underwent electrophysiologic study, we determined the anterograde E.R.P. of the accessory pathway and attempted to induce a reciprocating tachycardia in the supine and in the upright position. In 13 patients (72%) the anterograde E.R.P. of the accessory pathway shortened in the upright position (303 +/- 104 msec vs 331 +/- 123 msec; p less than 0.001); in 4 patients (22%) it was unchanged; in 1 patient was not defined, being inferior to the atrium E.R.P. We were able to induce a reciprocating tachycardia in 3 patients in the supine position, in 6 patients in the upright position. Electrophysiologic testing in the upright position improves the evaluation of the accessory pathway electrophysiologic properties.

Adolescent↗