Electrocardiographic characteristics of atrioventricular block induced by tilt testing

Abstract

(i) The occurrence of the AV block during neurocardiogenic reaction induced by TT is always preceded by sinus rhythm slowing and usually by PR interval prolongation. (ii) The AV block provoked by TT usually occurs at TT termination, but may occur even in the recovery period in a supine position. Sometimes the AV block may be present both at TT termination and during the recovery period.

Erratum

“…75,76 AV block provoked by tilt test represents the cardioinhibitory component of the neurocardiogenic reflex which is less frequent than sinus arrest, sinoatrial block, or sinus bradycardia (vagal stimulation on sinoatrial node usually predominates). Zysko et al reported an incidence of 5.2% of complete AV block in patients with positive tilt test, 77 similar to what had been previously found. 78 Sinus rhythm slowing or irregular sinus rhythm observed during (and sometimes preceding) the AV block due to neurocardiogenic reflex indicate its vagal origin.…”

Syncope Due to Idiopathic Paroxysmal Atrioventricular Block

“…Paroxysmal type 1C AV block is very rare during tiltinduced vasovagal syncope. Apart from 2 case reports (14,18), AV block with a constant P-P cycle has never been observed in large series of tilt-table tests (17,19). In the present study, tilt-table testing, which induced a vasovagal syncope in 7 cases, never reproduced AV block.…”

“…The 2 conditions frequently coexist, indicating a simultaneous vagal action on sinus node and AV node. Even when a more prominent AV response occurs, vagally mediated AV block is usually preceded by significant PR prolongation or Wenckebach; the P-P interval is prolonged markedly also during asystole, and there is significant PR prolongation on resumption of AV conduction (1,4,5,17). These features were absent in our patients, who were affected by abruptonset AV block without significant rhythm disturbances before or during the attack (type 1C block).…”

Paroxysmal Complete Atrioventricular Block: A Rare Cause of Syncope in Children

“…The two conditions frequently coexist, indicating a simultaneous vagal action on the sinus node and AV node. Even when a more prominent AV response occurs, vagally mediated AVB is usually preceded by significant PR prolongation or Wenckebach; the P-P interval is also prolonged markedly during asystole, and there is significant PR prolongation on resumption of AV conduction (12)(13)(14)(15)(16). These features, which suggest an idiopathic PAVB, were absent in our patient's ECG during the event.…”