A comparative analysis of antegrade and retrograde conduction patterns in man.

Abstract

SUMMARYPatterns of antegrade and retrograde conduction and refractory periods were studied using His bundle electrogram recordings, incremental atrial and ventricular pacing and the extrastimulus technique. In 36/50 patients antegrade conduction was "better" than retrograde conduction (group I), as evidenced by a) onset of retrograde atrioventricular (A-V) 766 Materials and MethodsRight heart catheterization was performed in the nonsedated postabsorptive state using local anesthesia. Fifty patients were studied for basic electrophysiological characteristics; in 40 of these patients, antegrade and retrograde refractory periods were determined. The experimental nature of the procedure was explained to all patients and signed consents were obtained. Electrode catheters were percutaneously introduced and fluoroscopically positioned in the region of 1) the lateral wall of the right atrium near its junction with the superior vena cava, to record from and stimulate the region of the high right atrium; 2) the tricuspid valve, to record bundle of His and low atrial activity;'4 3) the right ventricular apex or outflow tract, for ventricular pacing. Standard ECG leads and intracardiac electrograms (filter frequency settings 40-500 Hz) and timelines generated at 10, 100 and 1000 msec were displayed on a multichannel oscilloscope and recorded on magnetic tape. The records were subsequently replayed and recorded on photographic paper at a speed of 150 mm/sec.Atrial and ventricular pacing were accomplished using a programmed digital stimulator capable of delivering rectangular impulses of 1.5 msec duration at an adjustable milliamperage. Minimum milliamperage which allowed reliable capture for atrial (less than 2 ma) and ventricular pacing (less than 1 ma) was used. Starting at a rate slightly faster than sinus rhythm, the rate of stimulation was

Short QT Syndrome

“…16 Electrophysiological study confirmed that atrial and ventricular ERPs in these patients were significantly shorter than the lower border of the normal range. 17,18 The duration of the refractory periods of the myocardium is widely recognized to be an important parameter for the vulnerability of the heart to fibrillation at both atrial and ventricular levels.…”

Sustained bundle branch reentry as a mechanism of clinical tachycardia.

“…All pertinent conduction and refractory period intervals were measured as a part of the routine electrophysiologic study and have been previously published. 13 From the moment a sustained monomorphic VT was induced, particular attention was paid to the following. 1) Did the VT have a typical left or right bundle branch block pattern?…”

Intracardiac electrophysiological conduction parameters in adult dogs

“…AERP is achieved earlier than AVNERP, especially at a slow own rhythm or excess sympathetic tension. Noticeably, the hereby-documented reference values for the refractory periods of canine atria, atrioventricular node and ventricles differ markedly from the respective values for humans (Akhtar et al 1975;Josephson, 2002). The refractory periods of dogs turned out to be markedly shorter than those of humans.…”

“…Moreover, 13 (59%) dogs showed simultaneous block of the atrioventricular nodal and atrial conduction during the AVNERP and AERP determination. The sinoatrial node (45%), followed by the atrium (40%), are the primary sites in which the conduction block is observed during the refractory period determination in most humans (Akhtar et al 1975). AERP is achieved earlier than AVNERP, especially at a slow own rhythm or excess sympathetic tension.…”