BACKGROUND The hyperpolarization-activated nucleotide-gated channel--HCN4 plays a major role in the diastolic depolarization of sinus atrial node cells. Mutant HCN4 channels have been found to be associated with inherited sinus bradycardia. METHODS AND RESULTS Sixteen members of a family with sinus bradycardia were evaluated. Evaluation included a clinical questionnaire, 12-lead ECGs, Holter ...

BACKGROUND Fetal long QT syndrome (LQTS) is associated with complex arrhythmias including torsades de pointes and 2° atrioventricular block. Sinus bradycardia has also been associated with fetal LQTS, but little is known of this rhythm manifestation. Our purpose was to characterize the fetal heart rate (FHR)/gestational age (GA) profile of fetal LQTS. METHODS AND RESULTS We ascertained fetal ...

This report describes the clinical course of a patient with bradycardia and tachycardia-dependent atrioventricular block. Bradycardia dependent A-V block (phase 4 block) was transient and precipitated by spontaneous slowing of the sinus rate, atrial and ventricular extrasystoles; The degree of slowing (critical RP interval) required to induce A-V block increased progressively over a three-day p...

Grayanotoxin poisoning is most commonly seen in the East Black Sea Region of Turkey due to consumption mad honey, which made by bees from flowers rhododendron plant. Mad honey dose dependent. In low doses, it causes dizziness, hypotension and bradycardia. high can cause unconsciousness, seizures atrioventricular blocks. Local people are well aware generally do not go hospital for mild symptoms....

CARDIOVERSION has proved an effective and safe method for reverting ectopic arrhythmias to sinus rhythm.1'-" However, there is increasing evidence that capacitor electrical discharge may provoke arrhythmias in experimental animals12"-4 as well as in man.2' 6, 15 The majority of abnormal rhythms immediately following cardioversion are atrial in origin and are not serious. They generally represen...

Twenty-four children and young adults with electrocardiographic evidence of sinus node dysfunction (SND) are described. The patients, whose ages ranged from three days to 25 years, were divided into three groups based on the type of SND. Ten patients had persistent and inappropriate sinus bradycardia (group I): twelve patients had episodes of prolonged sinus arrest (group II); and seven patient...