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Biomedical subjects

F Gaita

Publications and source records attributed to F Gaita.

At least 73 records · Page 4Linked to original sources

[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↗

[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↗

Clinical and electrocardiographic features and long-term results of electrical therapy in patients with isolated His bundle disease.

The clinical, ECG, and electrophysiologic findings of 35 consecutive patients with second- and third-degree intra-His block with normal QRS complexes were examined. The follow-up period varied between 12 and 120 months (mean 45). Seventy-seven per cent of the patients were women. Underlying heart disease was present in 43% of the patients. ECGs were characterized by both second-degree type I and type II atrioventricular block, normal or slightly prolonged PR interval of the conducted beats or of the first conducted beat of a Wenckebach sequence, and by subtle changes in the initial forces of the QRS complexes of the escape beats. Electrophysiologic study showed normal sinus and atrioventricular node function and normal infra-His conduction in all patients. In four patients repetitive bradycardia-dependent intra-His block was induced. Thirty-two patients were permanently paced soon after the initial evaluation and three during the follow-up period. Total long-term mortality rate was 23%. None of the patients developed bundle branch block.

Adult↗

Short- and long-term effects of propafenone in ventricular arrhythmias.

The effectiveness of short- (15 days) and long- (12 months) term propafenone treatment was assessed in 53 patients presenting with more than 30 premature ventricular complexes per hour as detected by 24-hour ambulatory Holter monitoring. Thirty-nine patients had no apparent concomitant heart disease while 14 had chronic coronary artery disease. The effects of propafenone were analysed by ambulatory Holter monitoring after 15 days and at 3, 6 and 12 months. The initial dose was 150 mg four times daily and was increased up to 300 mg four times daily when necessary. Favourable short-term effects were obtained in 39 patients (73.6%). After 12 months, 17 patients (32.1%) were still on propafenone treatment with good results. Treatment was discontinued on account of low compliance in 28.3%. This was because treatment was ineffective even at high doses in 15.2%, because of severe side effects in 13.2%, because of proarrhythmic effects in 5.6% and for other causes in 5.6%.

Adolescent↗

Atrioventricular block complicating amiodarone-induced hypothyroidism in a patient with pre-excitation and rate-dependent bilateral bundle branch block.

As a clinical entity atrioventricular (AV) block due to hypothyroidism is rare. Such a case induced by hypothyroidism complicating long-term therapy with amiodarone in a 45 year old woman with pre-excitation is presented. Electrophysiologic data obtained before and during thyroxine replacement therapy showed that hypothyroidism lengthens the effective refractory period of the atria, AV node, bypass tract and His-Purkinje system (that in the ventricle not being measured); this lengthening resembles the effects of long-term administration of amiodarone. These observations suggest that depressed thyroid function may be protective against arrhythmias but a patient with preexisting conduction system disease may develop AV block. The tendency to develop AV block in a patient who is euthyroid was reduced by bypass tract conduction. These findings are significant not only in monitoring amiodarone effects during chronic prophylactic drug therapy but also in providing further insight into the complex interrelation between the action of the drug and the thyroid hormones on cardiac muscle.

Amiodarone↗

[Control of the efficacy of anti-arrhythmia drug therapy with the ambulatory electrocardiogram. Proposal for a new analytical statistical model].

Ambulatory electrocardiography is used for evaluating antiarrhythmic drug effectiveness. Statistical methods based on the analysis of the number of ventricular ectopic beats are currently employed. These techniques are not useful to compare groups of patients with different therapies, due to the wide spontaneous variability of the ectopic beats. We propose a new statistical method, based on the likelihood function. The new method has been tested both retrospectively on 102 patients treated with different antiarrhythmic drugs and prospectively on 12 patients subjected to three consecutive control ambulatory electrocardiograms and to a fourth one after treatment with propafenone. This new statistical method was found to be useful for comparing therapeutic effectiveness between groups of patients, whereas the traditional quantitative methods are to be preferred when drug effectiveness is evaluated in the single patient.

Adrenergic beta-Antagonists↗

Holter monitoring and provocative maneuvers in assessment of unipolar demand pacemaker myopotential inhibition.

Myopotential inhibition was produced by a combination of different provocative maneuvers in 423 (77%) out of 550 consecutive unipolar pacemaker patients. The most useful maneuvers were the hand-to-shoulder press (90% positivity) and the hand-to-hand press (60% positivity). Three groups of 20 patients were then submitted to 24 hours of Holter monitoring. Group A during the provocative maneuvers had shown myopotential inhibition and symptoms of cerebral ischemia. In group B symptomless myopotential inhibition had been induced. Group C had no myopotential inhibition nor symptoms during the tests. Abnormal pacemaker pauses related to myopotential inhibition were recorded during Holter monitoring in 90% of group A and in 80% of group B patients, but only group A patients showed symptoms. Thus in patients who are able to practice provocative isometric maneuvers and who can be selected according to their response, Holter monitoring seems to offer few advantages in discovering myopotential inhibition and related symptoms.

Adolescent↗

[Spontaneous changes of ventricular ectopic beats in ischemic patients and subjects without other signs of cardiopathy].

Spontaneous variability of premature ventricular complexes was evaluated by 72 hour continuous ambulatory electrocardiographic monitoring in 38 patients. Nineteen patients had coronary artery disease and 19 subjects had no documented signs of cardiac disease. Using multifactorial analysis of variance we determined the minimal percent reduction of premature ventricular complexes frequency that could not be ascribed to spontaneous variability alone in both single subject and in groups of 10 and 19 individuals and analyzed the difference between the two groups of ischemic and healthy patients. Our results show that in each subject with or without coronary artery disease the minimal reduction of premature ventricular complexes is similar: 71% and 72% respectively. On the other hand when the two groups were compared the percentage of reduction was 49% in healthy subjects and 40% in patients with coronary artery disease. Spontaneous variability of premature ventricular complexes decreases as the period of monitoring lengthens; however the improvement obtained with longer electrocardiographic monitoring doesn't justify the prolongation of the examination beyond 24 hours.

Aged↗

[Amiodarone in paroxysmal supra-ventricular tachycardias associated with sinus bradycardia].

The efficacy of amiodarone in the prevention of atrial tachycardia is well recognised. However, there remains some controversy over its use in patients with a basal sinus bradycardia because of the risk of further depression of sinus node function. We studied the effects of acute and chronic amiodarone therapy in 13 patients with paroxysmal supraventricular tachycardia and intercritical sinus bradycardias of between 40 and 50/min. All patients underwent electrophysiological investigation under basal conditions and after 5 mg/kg IV amiodarone. Five patients were excluded from chronic oral amiodarone therapy after IV amiodarone for the following reasons : sinus bradycardia of less than 30/min; sinus node recovery times greater than 2 s; 2nd or 3rd degree sino-atrial block. The other 8 patients were administered oral amiodarone on a long term basis. They were followed up clinically with dynamic ECGs every three months over a period of 1 to 3 years. All symptoms regressed in 6 patients. In one patient, the daily attacks of palpitations decreased to one a week. One patient did not improve. No cases of sino-atrial standstill were observed, although the sinus rate remained unchanged. The results of our study show that amiodarone may be administered for long periods in patients with sinus bradycardia and attacks of paroxysmal supraventricular tachycardia if the dynamic ECG during the waking hours shows a heart rate of no less than 40/min, and if electrophysiological investigations do not show significant depression of sinus node function after acute intravenous administration of the drug.

Adult↗

Bedside evaluation of atrioventricular block with narrow QRS complexes: usefulness of carotid sinus massage and atropine administration.

Second-degree intra-His bundle block is frequently of type I (Wenckebach periods) or 2:1. In this situation, the surface electrocardiogram does not permit distinction between intranodal (atrioventricular [A-V] and subnodal (intra-His) block. This study examined the value of bedside carotid sinus massage and atropine administration in diagnosing the site of block from the standard electrocardiogram in subjects with chronic A-V block and narrow QRS complexes. Fifteen patients had intra-His bundle block and 10 had intranodal block. The combination of two tests correctly located the site of block in 22 subjects, and was noncontributory in 3. Thirteen of the 15 intra-His bundle blocks and 9 of the 10 intranodal blocks were properly identified; in three cases the results were nondiagnostic, but no wrong diagnoses were made. The noninvasive bedside method of carotid sinus massage and the use of atropine permit both the localization and the determination of the type of block in the majority of cases of second degree A-V block and narrow QRS complexes. In a proper clinical context they can obviate the need for invasive electrophysiologic studies.

Adult↗

[Serum levels and kinetics of digoxin in patients with hyperthyroidism (author's transl)].

The mechanism of reduced sensitivity to digitalis in patients with hyperthyroidism has been attributed to a change of intrinsic myocardial function and/or to altered pharmacokinetics of cardiac glycosides. Digoxin kinetics have been studied in hyperthyroid and 8 euthyroid patients after a single oral and i.v. dose at steady-state. Plasma and urinary digoxin concentrations were determined by radioimmunoassay. A significantly mean lower serum digoxin concentration was found in hyperthyroid patients, both after a single oral drug administration and at the steady-stage. A decreased digoxin absorption could not account for this finding, since both the percentage of gastrointestinal uptake of the drug and maximal serum concentration did not differ in hyperthyroid patients as compared to controls. Hyperthyroid subjects showed, on the contrary, an expended distribution volume and a significantly higher excretion, as documented by a lower drug half-life, by the increase of the elimination constant and urinary digoxin output.

Adult↗