Paradoxical Ventriculophasic Arrhythmia in a Patient with 2:1 Atrioventricular Block: A Rare Phenomenon

Abstract

Atrioventricular block; Parodoxical; Ventriculophasic arrhythmiaVentriculophasic arrhythmia is a phenomenon commonly seen in patients with complete atrioventricular (AV) block. The usual observation is that the PP intervals containing the QRS complex are shorter in duration than the PP intervals without an intervening QRS complex. And also an inverse relation is seen between the QP interval and the subsequent PP interval without a QRS complex. We report a case of paradoxical ventriculophasic arrhythmia in an 85-year-old patient presenting with 2:1 AV block, wherein the PP intervals containing the QRS complex are longer than the PP intervals without a QRS complex. CASE REPORTAn 85-year-old woman was admitted to our facility with a 4-day duration of fatigue and progressive worsening of shortness of breath on exertion. She denied any chest pain, palpitations, and syncope. She was not on any medications. On admission, she was registering a blood pressure of 160/68 mmHg, heart rate of 40 beats per minute, and oxygen saturation of 95% on 2 liters of oxygen. The 12-lead electrocardiogram ( Fig. 1) showed sinus rhythm, left bundle branch block, and second-degree AV block with 2:1 AV conduction. The PP intervals containing the QRS complex are longer (800 milliseconds) than the PP intervals without a QRS complex (720 milliseconds) which is the paradox of ventriculophasic arrhythmia. Also to be noted that the QP interval is also quite prolonged at 620 milliseconds. She received a dual-chamber pacemaker for symptomatic high-grade AV block. DISCUSSIONVentriculophasic arrhythmia is most commonly observed in patients with complete heart block. It has been also reported in patients with seconddegree heart block, paroxysmal atrial tachycardia with block and ventricular paced rhythms. The usual observation is that the PP intervals containing the QRS complex are shorter in duration than the PP intervals without an intervening QRS complex. This phenomenon was first observed and described by Erlanger and Blackman in an animal study on chronic AV block. 1 Further studies reported 40-50% incidence of this phenomenon in patients with complete heart block and paced rhythms. 2-4 A paradoxical effect in which PP intervals containing the QRS complex are longer than the PP intervals without a QRS complex has been seen in 3.5% of cases with complete heart block.Dadu and McPherson proposed a quantitative definition of ventriculophasic phenomenon based on a study on ventriculophasic response and its clinical correlations in complete heart block patients with pacemaker. 4 They observed that the shortening of PP interval mainly occurred when the interposed QRS occurs in the first 60% of the anticipated PP interval. They defined ventriculophasic response as being present during heart block when an interposed QRS occurring in the first 60% of the anticipated PP interval results in a greater than 3% shortening of % PP interval surrounding the QRS compared to the preceding PP interval. The exact mechanism of this phenomenon is still unclear. The prop...

A 2:1 atrioventricular block presenting paradoxical ventriculophasic response

“…Two cases describing the paradoxical VR during 2:1 AV block have been reported (Liu, Shehata, & Wang, 2010;Manne, 2016). Our case has two important clinical issues that were not described in the previous two cases.…”

“…To the best of our knowledge, our case is the third one describing paradoxical VR during a 2:1 AV block (Liu et al, 2010;Manne, 2016). Furthermore, a 2:1 AV block presenting typical VR, as well as paradoxical VR, has not yet been reported.…”