Heart block

A Patient With Hypertrophic Cardiomyopathy Presenting in Cardiac Arrest

“…Wenckebach and Winterberg 3 proposed in 1927 that the arrhythmia was owing to improvement in the blood supply to the sinoatrial node after ventricular contraction, which accelerates the discharge of the sinus impulse; during periods of ventricular asystole, the sinoatrial pacemaker is depressed. In 1944, Parsonnet and Miller 4 proposed that there is an increase in intra-atrial pressure following ventricular contraction, which excites the Bainbridge (atrial) reflex, resulting in vagal inhibition and subsequent acceleration of the sinoatrial nodal pacing cells.…”

ECG of the Month

“…Classically, the P-P intervals that encompass a QRS complex are shorter than those that do not encompass a QRS complex. [7][8][9][10] Ventriculophasic sinus arrhythmia may also develop with complete AV block or in the presence of ventricular premature complexes with a full compensatory pause. [7][8][9][10] The mechanism responsible for the occurrence of ventriculophasic sinus arrhythmia is unknown, but several mechanisms have been proposed.…”

“…[7][8][9][10] Ventriculophasic sinus arrhythmia may also develop with complete AV block or in the presence of ventricular premature complexes with a full compensatory pause. [7][8][9][10] The mechanism responsible for the occurrence of ventriculophasic sinus arrhythmia is unknown, but several mechanisms have been proposed. 11 The most likely explanation appears to be that an increase in intra-atrial pressure following contraction excites the Bainbridge reflex, resulting in vagal inhibition with acceleration of sinus node discharge.…”

An Electrokymographic Study of Auricular Arrhythmia in Total Heart Block

“…Auricular arrhythmia is often observed in total A-V block (ER-LANGER and BLACKMAN 1909-10, HECHT 1913, PARSONNET and MILLER 1944 and others). The auricular intervals which include a ventricular contraction, are as a rule shorter than the intervals appearing in ventricular diastole.…”