Paradoxical response during Para-Hisian pacing in a case with fasciculo-ventricular pathway: What is the mechanism?

Causes of paradoxical response include Pure His capture and inadvertent intermittent direct atrial capture. In the index case , we postulate that the likely mechanism of paradoxical prolongation could be due to decrement in the AV node due to the shortening of HH interval which happened as a result of a narrower H + Vc beat .

Metal and acid-free synthesis of acenaphthenone-2-ylidene ketones in PEG 400 and their radical nitration by TBN in water.

The synthesis of acenaphthenone-2-ylidene ketones has been developed using PEG 400 as a solvent under metal and acid-free conditions. Using TBN as a nitrating agent under atmospheric oxygen, nitration of acenaphthenone-2-ylidene ketones has been accomplished for the first time. Upon nitration, ()-2-(2-oxo-2-phenylethylidene)acenaphthylen-1(2)-one and alkyl ()-2-(2-oxoacenaphthylen-1(2)-ylidene)acetate give the diastereomer with the same geometry.

Paradoxical under-sensing of atrial lead at high sensitivity setting in dual chamber pacemaker during atrial flutter - What is the mechanism?

The causes of atrial undersensing in a dual chamber pacemaker include true undersensing (low amplitude electrogram), functional undersensing (related to the effect of special timing cycles in the presence of an adequate signal) and paradoxical undersensing. This case report describes paradoxical atrial undersensing at a higher programmed atrial sensitivity and with the return of normal atrial sensing at a lower programmed sensitivity.