The history of the Wolff-Parkinson-White (WPW) syndrome is a 50-year–long tale of speculation and discussion among physiologists, anatomists, and clinicians about how to explain the frequently occurring tachycardias in patients showing a strange ECG.1 That riddle was solved in 1967 in Amsterdam when Durrer and associates2 showed that the WPW syndrome was based on a second connection between the...

Ventricular preexcitation, which characterizes Wolff-Parkinson-White syndrome, is caused by the presence of accessory pathways that can rapidly conduct electrical impulses from atria to ventricles, without the intrinsic delay characteristic of the atrioventricular (AV) node. Preexcitation is associated with an increased risk of tachyarrhythmia, palpitations, syncope, and sudden death. Although ...

BACKGROUND Cardiac Resynchronization therapy (CRT) remains largely under-used in developing countries owing to the high cost of therapy. In this pilot study, we explore 'optimized' Left Ventricle Only Pacing (LVOP) as a cost effective alternative to cardiac resynchronization therapy in selected patients with heart failure. HYPOTHESIS In economically poorer patients with heart failure, left bu...

During failure of the sinoatrial node, the heart can be driven by an atrioventricular (AV) junctional pacemaker. The position of the leading pacemaker site during AV junctional rhythm is debated. In this study, we present evidence from high-resolution fluorescent imaging of electrical activity in rabbit isolated atrioventricular node (AVN) preparations that, in the majority of cases (11 out of ...

Calcium channel blockers depress atrioventricular (AV) nodal properties in vivo in a frequency-dependent manner, suggesting that selective drug action during supraventricular arrhythmias may result from use-dependent properties. The present study was designed to examine whether or not the rate-dependent actions of diltiazem account for its therapeutic effects during atrial fibrillation. The det...

Second-degree atrioventricular (AV) nodal block with 2:1 AV conduction during atrioventricular nodal reentrant tachycardia (AVNRT) has been previously described. We report a patient who developed AVNRT during which 3:1 intra-infra-Hisian block due to catheter manipulation was observed. This was followed by gradual, incremental recovery of AV conduction. AVNRT accounts for approximately 50% of c...

In the His bundle and ventricular electrograms of Langendorff-perfused guinea pig hearts driven at a cycle length of 450 or 700 msec, S-1389 (711389-S), a new antiarrhythmic agent, above 3 x 10(-7) or 10(-6) M increased the basal conduction times in the following order: His-Purkinje system greater than ventricular and atrial muscles greater than atrioventricular (AV) node. Slowing of the ventri...

OBJECTIVE To examine the hypothesis that the anatomic equivalents of the fast and slow pathways identified in patients with atrioventricular (AV) nodal tachycardia may be universal and represent the principal sites of atrial input into the normal compact AV node. METHODS 15 patients undergoing complete AV junction ablation for paroxysmal atrial fibrillation were studied. Radiofrequency energy...

A 21 year old man presented with multiple, recurrent episodes of complete atrioventricular (AV) block associated with swallowing. Electrophysiological study revealed an AV block with swallowing of carbonated beverages and balloon inflation in the lower oesophagus. Evaluation did not demonstrate any underlying oesophageal or cardiac disease, and the AV block was not induced after intravenous atr...