Atrioventricular (A-V) conduction, ventriculo-atrial conduction and mechanism of tachycardia were studied by programmed electrical stimulation before and after the administration of ouabain in 15 patients suffering from paroxysmal supraventricular re-entrant tachycardia. In 13 patients the tachycardia circuit was confined to the A-V node. In two patients the stimulation study showed that an acc...

INTRODUCTION The purpose of this study is to describe a simple and reliable diagnostic maneuver that allows for the rapid differentiation of atypical AV nodal reentrant tachycardia (AVNRT) from other causes of long RP tachycardia. Long RP tachycardias may be caused by atypical AVNRT, orthodromic reciprocating tachycardia (ORT) involving a slowly conducting retrograde accessory pathway, or atria...

In the differential diagnosis of broad-complex tachycardia, the most important decision is whether or not the tachycardia is ventricular, since this type carries the worst prognosis. However, the rules for a diagnosis of ventricular tachycardia are so complex that they are not satisfied in many cases, and the default diagnosis, supraventricular tachycardia, is erroneously accepted. We sought to...

A 66-year-old woman with a 24-year history of paroxysmal supraventricular tachycardia underwent an electrophysiologic procedure. The baseline sinus cycle length, atrial-His (AH), and Hisventricular (HV) intervals were 8(X). 70, and 40 msec, respectively. Programmed stimulation with a single atrial extrastimulus did not demonstrate dual AV nodal physiology and did not result in the induction of ...

Of 67 patients with reciprocal atrioventricular (A-V) nodal tachycardia consecutively studied by programmed electrical stimulation of the heart, nine patients showed second degree block toward the ventricle and one patient toward the atrium during tachycardia. In four patients the occurrence of block was critically related to the prematurity of the test stimulus initiating the tachycardia. In t...

Catheter ablation of ventricular tachycardia (VT) currently has an important role in the treatment of incessant ventricular tachycardia and reduction of the number of episodes of recurrent ventricular tachycardia. Conventional mapping techniques require ongoing tachycardia and haemodynamic stability during the procedure. However, in many patients with scar-related ventricular tachycardia, non-i...

OBJECTIVES This study demonstrates that exercise-provocable tachycardia resembling right ventricular outflow tract tachycardia may originate from the anterobasal left ventricle. BACKGROUND Reentry is the operative mechanism of idiopathic left ventricular tachycardia, with a QRS complex of right bundle branch block and superior axis that is responsive to verapamil but not adenosine. Whether so...

OBJECTIVES The purpose of this study was to determine the efficacy and risks of radiofrequency ablation of various forms of supraventricular tachycardia after Mustard and Senning operations for d-transposition of the great arteries. BACKGROUND In this patient group, the reported success rate of catheter ablation of intraatrial reentry tachycardia is about 70% with a negligible complication ra...

The effect of electrically induced auricular and ventricular tachycardia of various rates was studied in the anesthetized dog. When, the control heart ranging between 140 and 190 per minute, atrial tachycardia of a rate only slightly higher than the control rate was induced, a very temporary initial decrease in arterial blood pressure, cardiac output and coronary blood flow occurred, then all t...