Apparent bradycardia-dependent advanced second-degree atrioventricular block

Thalidomide-Induced Sinus Bradycardia

“…10 Disease states associated with bradycardia include inferior myocardial infarction, myocarditis, sinus node fibrosis, sick sinus syndrome, autonomic neuropathy, and hypothyroidism. 10–15 Medications such as β-blockers, calcium-channel blockers, digoxin, quinidine, and amiodarone are also common causes of sinus bradycardia. 16…”

Symptomatic, Inspiration‐Induced Atrioventricular Block: Treated with Pacemaker Implant

“…While RSA was classically described during relaxed respiration, it has been shown that changes are more obvious during deep breathing . The reported case illustrates the classic form of RSA during relaxed respiration, but with paradoxical response on deep inspiration, associated with AV block, that might result from a different autonomous nervous system behavior. AV block: The presence of breathing‐induced AV block was first reported by Katoh et al., but unlike our case, all appeared in the expiratory phase of respiration . Among the proposed electrophysiological mechanisms that could explain such bradyarrhytmia are the supernormality phenomenon, the Wedensky phenomenon, and others.…”

“…AV block: The presence of breathinginduced AV block was first reported by Katoh et al, but unlike our case, all appeared in the expiratory phase of respiration. 3,4 Among the proposed electrophysiological mechanisms that could explain such bradyarrhytmia are the supernormality phenomenon, the Wedensky phenomenon, and others. In the present case, the disorder appears to be located in one of the pathways involved in the RSA.…”

Unexpected, Dramatic Improvement in Atrioventricular Conduction During Pacemaker Implantation for Apparent Complete Heart Block

“…Given the persistence of AV block with slower sinus rates, but not at faster ones, one could postulate a Phase 4 or bradycardia dependent type of block that improves with more rapid atrial pacing 4 . Similar cases have been previously described 5,6 . Since AV nodal conduction velocity lengthens at faster pacing cycles, the level of block is more likely in the His‐Purkinje system.…”

“…4 Similar cases have been previously described. 5,6 Since AV nodal conduction velocity lengthens at faster pacing cycles, the level of block is more likely in the His-Purkinje system. Evidence for this lies in the fact that AV conduction occurred with a right bundle branch block-type intraventricular conduction delay.…”