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Biomedical subjects

G Inama

Publications and source records attributed to G Inama.

At least 55 records · Page 3Linked to original sources

Familial endemic persistent atrial standstill in a small mountain community: review of eight cases.

Familial persistent atrial standstill (PAS) has been rarely documented. Five patients, three male and two female (mean age 46 years at first observation), with familial 'complete' PAS, all from a small mountain community (900 residents) have been studied. Diagnostic criteria were: absence of P wave in any lead of the standard electrocardiogram; no electrical activity of the atria with extremely slow junctional escape rhythm on the endocavitary recordings; lack of atrial excitability; absence of atrial wall movement at fluoroscopy; no mitral A wave on the echocardiogram. All patients had marked cardiac enlargement primarily due to atrial enlargement and all had impaired functional class. Some had bradycardia for many years but none had syncope. Permanent cardiac pacing was carried out in all. Two had cerebral embolism. In the same community there were three patients, one male and two female (mean age 34 years at first observation), with 'partial' atrial standstill characterized by absence of P waves in any lead of the standard electrocardiogram and by endocavitary recording of electrical activity limited to a localized region of the atrium. These three patients also had cardiac enlargement primarily due to atrial enlargement but to a lesser degree than the patients with complete PAS. One patient had cerebral embolism. The familial and endemic character of the disease is stressed. Cardiac enlargement due primarily to atrial enlargement seems to be a common feature of both the complete and partial form of the PAS syndrome.

Adult

Evidence of a reentry circuit in the common type of atrial flutter in man.

To investigate the mechanism of atrial flutter (AF) in humans, we studied 13 patients during episodes of spontaneous common AF, with simultaneous multiple atrial endocavitary recordings and atrial programmed stimulation. In all patients, low paraseptal atrial activation preceded high right atrial activation, and the latter preceded mid- or low lateral right atrial activation (recorded in five patients). Programmed atrial stimulation resulted in early reset of the AF cycle, with an unchanged poststimulation AF activation pattern. The poststimulation cycle recorded from an even potential to the site of stimulation was always shorter than the basic flutter cycle length. The poststimulation cycle recorded at the site of stimulation was always equal to or longer than the flutter cycle length. These results strongly favor the existence of a reentry circuit to which the extrastimulus has access.

Adult

[Validity and limits of invasive pharmacological tests in the treatment of malignant ventricular hyperkinetic arrhythmias].

Programmed stimulation can now be safely performed for the evaluation of therapy for recurrent ventricular tachyarrhythmia. The initiation of ventricular tachycardia appears closely related to its actual spontaneous clinical occurrence. Serial electrophysiologic studies can be performed and are effective in prospectively evaluating the response to antiarrhythmic drugs. The efficacy of therapy based on the results of programmed stimulation appears to be good. On the other hand, Amiodarone can be effective in the chronic treatment as well as in patients with ineffective acute drug test.

Adult

Overdrive and programmed atrial electrostimulation in the study of the electrogenetic mechanism of atrial flutter in man.

The response of atrial flutter (AF) to programmed atrial stimulation (PAS) (13 cases) and overdrive atrial pacing (OAP) ws studied in a total of 18 patients. During PAS the return cycle was equal to the basic cycle of AF in six patients, shorter in one patient, and slightly longer in six; it was never compensatory. ATrial flutter terminated in two patients by PAS and by OAP in three. In 4 patients, PAS resulted in an acceleration of the AF rate, followed by spontaneous interruption within 2 seconds. In the remaining patients, the stimulation either converted the AF into an uncommon type of AF (two patients) or into atrial fibrillation that was followed by spontaneous return to sinus rhythm. In two patients it was possible to reproduce the AF with PAS; in one of the patients another type of AF was induced. Some of the data observed suggest a re-entry circuit as the electrogenetic mechanism responsible for AF in man.

Adult

[The phenomenon of accelerated A-V conduction. Electrophysiological study with a "selective" calcium antagonist (Verapamil)].

In order to discover slow response calcium dependent fibers within the structure with enhanced A-V conduction, an acute i.v. test with Verapamil (a highly selective calcium antagonist) was done in 13 patients with enhanced A-V conduction syndrome (4 had A-V by-pass, Kent type, associated). The action of Verapamil on the following parameters was studied: 1) A-H interval in sinus rhythms; 2) delta A-H interval (i.e. the maximum increment of A-H interval after incremental atrial pacing); 3) antegrade and retrograde function curves of the structure with enhanced A-V conduction; 4) R-R cycle of the reciprocating tachycardia, antegrade and retrograde conduction time (after identification of the reentry circuit) and pattern of induction and interruption of the tachycardia. Only in 1 patient a total atrio-hisian by-pass was identified. In all the other patients the electrophysiologic response to i.v. Verapamil suggested the presence of slow response calcium dependent fibers within the structure with enhanced A-V conduction which was always depressed by the drug even if to a lesser degree than in a normal A-V node. From these data and from the analysis of the epidemiology of enhanced A-V conduction, the Authors hypothesize that an infantile type A-V node could be in most cases the anatomical basis of enhanced A-V conduction while only rarely a total or partial A-V node by-pass.

Adolescent

[Another type of interaction between blood levels of digitalis and anti-arrhythmic drugs: digoxin and amiodarone. Experience with long-term therapy].

In clinical Arrhythmology it is often necessary to associate digitalis and antiarrhythmic agents. This calls for study of possible interaction between the employed drugs. We found a statistically significant correlation between digitalis and amiodarone plasma level in patients on long term treatment with both drugs. A statistically significant linear correlation between plasma amiodarone level and digoxin (0.25 mg/day) or beta-methyldigoxin (0.20 mg/day) was documented in 33 patients. 23 patients had been treated with these drugs for paraxysmal reciprocating supraventricular tachycardia since an average of 52 months (computerized follow-up). (Amiodarone average weekly dose was 1078 +/- 168 mg after a loading dose of 12 gm given over one month). 10 patients were on chronic treatment with higher weekly doses of amiodarone (average dose 2380 +/- 731 mg per week). Thyroid function tests (T4; T3; T3UP; TSH; rT3) were checked in every patients. Further studies are warranted to understand the mechanism of the interaction between amiodarone and digitalis. As a clinical implication we point out that amiodarone-digoxin (or betamethyldigoxin) interaction in our patients has neither resulted in over-therapeutic plasma level nor in signs of digitalis toxicity.

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