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Biomedical subjects

J Pimenta

Publications and source records attributed to J Pimenta.

At least 55 records · Page 3Linked to original sources
PubMed1986

Effects of atenolol in patients with reciprocating supraventricular tachycardia.

We studied 12 patients with crisis of paroxysmal reciprocating supraventricular tachycardia before and after intravenous injection of 5 mg of atenolol. The patients were then followed for periods ranging from 6 to 50 months (median 34 months). During this time, they received oral atenolol therapy, at 200 mg for the first two weeks, and 100 mg daily thereafter. Tachycardia was due to reciprocation within the atrioventricular node in 9 patients, and to pre-excitation in 3 patients. Atenolol slowed the sinus rate, prolonged the atrioventricular conduction time, and increased the atrial cycle length at which atrioventricular nodal Wenckebach phenomenon occurred. During the tachycardia, atenolol increased the tachycardia During the tachycardia, atenolol increased the tachycardia cycle length, due to prolongation of the intranodal atrioventricular conduction time. Of the 11 patients who were observed for the full period, 7 had no further episodes of arrhythmia. One patient (with left-sided pre-excitation) failed to respond to any antiarrhythmic medication, one patient remained free of symptoms for two years, but received an atrial pacemaker for control of the tachycardia at the end of this period. Two patients (one with dual atrioventricular nodal pathways, and one with concealed left-sided pre-excitation) await other treatment for their tachycardia, after remaining free of symptoms for one and two years, respectively. These findings suggest that atenolol is an effective beta blocker for use in controlling arrhythmias in patients with reciprocating supraventricular tachycardia, for use in once daily dosage, and is a medication largely free of side effects.

Adult↗
PubMed1986

Tachycardia mediated by an AV universal (DDD) pacemaker triggered by a ventricular depolarization.

A 44-year-old female had Chagas' disease with right bundle branch block, right axis deviation, and ventricular ectopic beats. An invasive evaluation showed a prolonged HV interval of 100 ms. A Medtronic Versatrax 7000 was implanted, after which a pacemaker-mediated tachycardia was observed. The esophageal lead ruled out the possibility of an atrial triggered tachycardia. The diagnosis was pacemaker-mediated tachycardia due to abnormal sensing of the terminal forces of the ventricular activation because of malposition of the atrial lead in the right ventricular out-flow tract.

Adult↗
PubMed1983

Electrophysiologic findings in long-term asymptomatic chagasic individuals.

Under electrophysiologic studies, 44 asymptomatic chagasic individuals were studied. The mean age was 39.9 years, with 26 being male. The surface ECG showed normal tracings in 12 patients, left anterior fascicular block in three, incomplete right bundle branch block in two, and right bundle branch block in 27 (isolated in six, associated with left anterior fascicular block in 19 and with left posterior fascicular block in two). Sinus nodal dysfunction was found in eight (18.1%), and 29 (66%) presented with some form of abnormal AV nodal behavior during atrial stimulation. Repetitive ventricular beats were recorded in 17 (41.4%) patients. Finally, in 19 (43.1%), patterns of dysfunction at two or more levels of the cardiac conducting system were found. It is concluded that the chagasic cardiomyopathy produces diffuse lesions in the conducting tissue of the human heart in the stages when the disease is detected, and that the individuals are still asymptomatic.

Adult↗
PubMed1980

Abnormal atrioventricular nodal response patterns in patients with long-term Chagas' disease.

Thirty-two volunteers with positive serologic tests for Chagas' disease were submitted to electrophysiologic studies. No one had documented tachyarrhythmias, heart failure, PR interval shorter than 0.12 or longer than 0.20 msec, pre-excitation or cardiac enlargement. The atrioventricular (AV) nodal function study under programmed atrial stimulation revealed abnormal AV nodal function in nine (28.1 percent) with long-term Chagas' disease. Due to the high incidence of the longitudinal dissociation in this disease, and based on previously reported histopathologic findings that demonstrate the involvement of the right side of the AV node and His bundle, this study suggests that the abnormal AV nodal responses may be secondary to the organic alterations produced by Chagas' disease.

Adult↗
PubMed1978

Double ventricular response to an extrastimulus in a patient with triple atrioventricular pathways.

A patient with the Wolff-Parkinson-White Syndrome was studied through recordings of the intracardiac potentials and programmed atrial stimulation. During programmed atrial stimulation at progressively shorter coupling intervals (A1-A2 intervals), the His deflection was always recorded after the ventricular complex. Thus, at coupling intervals between 295 and 250 msec, there was a double ventricular response, one through the accessory pathway (QRS complex of the Wolff-Parkinson-White morphologic pattern) and the other by the normal atrioventricular pathway (normal QRS complex or with pattern of left bundle-branch block). At a coupling interval of 295 msec, the atrio-His (A-H) interval increased from 200 to 350 msec. This fact and the presence of two distinct A2-H2 intervals are suggestive of the existence of dual atrioventricular pathways, coexisting functionally with a lateral accessory bypass (Kent's bundle).

Bundle of His↗