OBJECTIVES The purpose of this study was to examine whether P wave signal-averaged electrocardiogram (P-SAECG), which detects subtle changes in P wave, detects the concealed accessory atrioventricular pathway (AP). BACKGROUND It is difficult to differentiate atrioventricular reciprocating tachycardia (AVRT) due to the AP from atrioventricular nodal reentrant tachycardia (AVNRT) when the ventr...

Electrocardiographic excerpts from three patients demonstrate bigeminy, concealed bigeminy, trigeminy, concealed trigeminy, and Wenckebach's pattern of variation in the coupling interval from sinus beat to ventricular ectopic beat. These diverse manifestations of ventricular ectopy support the hypothesis that reentry in man reflects conduction of an initial impulse, with delay, to cause the cou...

Pre-eclampsia and eclampsia are well-known risk factors of posterior reversible encephalopathy syndrome. Early recognition and proper treatment result in complete reversibility of this disease. Concealed pregnancy obstacles a safe prenatal care and a safe planned delivery, because of latency in the diagnosis. We present a case of unrecognized posterior reversible encephalopathy syndrome, eclamp...

Although concealed conduction in the atrioventricular node (AVN) has been the focus of numerous experimental and clinical studies, little is known about the differential effects on AVN functional behavior of prior concealed retrograde impulse penetration alone vs prior anterograde or dual AVN activation. This study was undertaken specifically to investigate this aspect of human AVN physiology i...

The number of resonance structures (SC) for previously published concealed non-Kekuléan benzenoid hydrocarbons is determined. Using a simple computer program, analytical expressions for determining SC for various classes of non-Kekuléan (free-radical) benzenoid hydrocarbons are derived, and some properties of concealed non-Kekuléan benzenoid hydrocarbons are studied.

Exit block from a parasystolic focus is recognized when automatic discharges fail to become manifest during the excitable phase of the ventricular cycle. In the present study, an apparently complete exit block and a persistently concealed ventricular parasystole (VP) resulted from an exit refractory period (ExRP) longer than the sinus cycle length. Slowing of the heart rate caused the concealed...