Search PubMed⌕ Search

Biomedical subjects

C E Duffy

Publications and source records attributed to C E Duffy.

44 records · Page 3Linked to original sources
PubMed1982

Electrophysiologic study demonstrating triple antegrade AV nodal pathways in patients with spontaneous and/or induced supraventricular tachycardia.

Ten patients are described with two discrete discontinuities in AV nodal conduction curves suggesting triple antegrade AV nodal pathways. This represents approximately 6% of patients seen in this laboratory with dual AV nodal pathways. Patients ranged in age from 18 to 63 (mean +/- SD, 48 +/- 15 years). Six of the 10 patients had organic heart disease and four did not. The effect of cycle length on triple pathways could be analyzed in 8 of 10 patients who had atrial extrastimulus testing at two or more cycle lengths. Three of these eight patients had triple pathways at all tested cycle lengths. Four patients had triple pathways only at shorter cycle lengths. One patient had triple pathways only at longer cycle lengths. Intact retrograde conduction was demonstrated in seven of ten patients, all of whom had atrial echoes (two patients) or inducible supraventricular tachycardia (SVT) (five patients). Echoes or SVT were induced on the slow pathway is all seven patients, but also on the intermediate pathway in three. However, sustained SVT usually reflected antegrade slow and retrograde fast pathway conduction. In conclusion, triple AV nodal pathways may be demonstrated in occasional patients during atrial extrastimulus testing. Thereby, functional longitudinal dissociation of the AV node is not limited to two pathways.

Adolescent↗
PubMed1981

Retrograde dual atrioventricular nodal pathways.

Thirty-one (3.5 percent) of 887 studied patients had retrograde dual atrioventricular (A-V) nodal pathways, as manifested by discontinuous retrograde A-V nodal conduction curves (29 patients) or by two sets of ventriculoatrial (V-A) conduction intervals at the same cycle length (2 patients). All patients had A-V nodal reentrant ventricular echoes of the unusual variety induced with ventricular stimulation (25 patients had single, 2 patients had double and 4 patients had more than three ventricular echoes). The weak link of the reentrant circuit was always the retrograde slow pathway. Eleven of the 31 patients also had anterograde dual A-V nodal pathways (bidirectional dual pathways). Eight patients (26 percent) had spontaneous as well as inducible A-V nodal reentrant paroxysmal supraventricular tachycardia (of the unusual type in three and the usual type in five). In addition, three patients (10 percent) had only inducible supraventricular tachycardia (two of the unusual and one of the usual type). Retrograde dual A-V nodal pathways are uncommon. They are associated with the finding of at least single A-V nodal reentrant ventricular echoes (all patients), anterograde dual pathways (one third of patients) and A-V nodal reentrant paroxysmal supraventricular tachycardia of the usual and unusual variety (one third of patients).

Adult↗
PubMed1981

Procainamide-induced polymorphous ventricular tachycardia.

Seven cases of procainamide-induced polymorphous ventricular tachycardia are presented. In four patients, polymorphous ventricular tachycardia appeared after intravenous administration of 200 to 400 mg of procainamide for the treatment of sustained ventricular tachycardia. In the remaining three patients, procainamide was administered orally for treatment of chronic premature ventricular contractions or atrial flutter. These patients had Q-T prolongation and recurrent syncope due to polymorphous ventricular tachycardia. In four patients, the arrhythmia was rapidly diagnosed and treated with disappearance of further episodes of the arrhythmia. In two patients, the arrhythmia degenerated into irreversible ventricular fibrillation and both patients died. In the seventh patient, a permanent ventricular pacemaker was inserted and, despite continuation of procainamide therapy, polymorphous ventricular tachycardia did not reoccur. These seven cases demonstrate that procainamide can produce an acquired prolonged Q-T syndrome with polymorphous ventricular tachycardia.

Administration, Oral↗
PubMedDate not supplied

Inducible polymorphous ventricular tachycardia following Mustard operation for transposition of the great arteries.

A 22-year-old woman with chronic atrial tachycardia following Mustard's operation for transposition of the great arteries presented with dizziness and ventricular tachycardia documented with dynamic 24-h electrocardiogram. During intracardiac electrophysiology study, programmed ventricular extrastimulation induced polymorphous ventricular tachycardia (torsades de pointes). This was prevented by intravenous administration of procainamide. We postulate that polymorphous ventricular tachycardia is a possible cause of death in patients with Mustard's operation. Postoperative electrophysiologic study may define those patients at risk to develop this potentially fatal arrhythmia.

Adult↗
PubMedDate not supplied

Doppler echocardiography with extended transesophageal atrial pacing: predicting the efficacy of permanent atrial pacing in the patient with a small left ventricle and sinus node dysfunction.

A 2100-g neonate underwent a two-ventricular surgical repair of a right ventricle-dominant unbalanced atrioventricular septal defect associated with the heterotaxy syndrome and sinus node dysfunction. Postoperative congestive heart failure persisted despite bradycardia management by temporary ventricular pacing. Spectral Doppler echocardiographic analysis of pulmonary venous inflow and aortic outflow patterns demonstrated significant improvement with transesophageal atrial pacing. Extended transesophageal pacing was performed for two days, resulting in dramatic clinical improvement. This is the first report of extended transesophageal atrial pacing complementing Doppler echocardiography predicting an improved outcome with permanent atrial pacing.

Arrhythmia, Sinus↗