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Dual-Chamber Pacemaker Function in Complete Heart Block

Image 2 of 3 in Series "Progression of Significant Conduction Disease to require Dual-Chamber Pacemaker before CRT-D Upgrade"

Description

An underlying rhythm of complete heart block supported fully by dual-chamber pacing programmed with rate-adaptive sensing and pacing of both the right atrium and ventricle (DDDR). Best seen in the full strip of Lead V5 at the bottom of this EKG, nearly every atrial and ventricular beat is preceded by a pacer spike besides the 7th beat with much different morphology than the others. It is important to note the wide QRS of 218 ms and left bundle branch block (broad M shaped R wave in Leads I, aVL) from isolated right ventricular pacing.

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This image is part of the series "Progression of Significant Conduction Disease to require Dual-Chamber Pacemaker before CRT-D Upgrade"

Other images in this series

Atrioventricular and Bifascicular Blockade Preceding Progression to Complete Heart Block

by: Matthew T. Brown, MD; Mary M. Pelling, BSE

Normal sinus rhythm with evidence of significant conduction disease. 1st degree atrioventricular block is present with prolonged PR interval of 280 ms. Right bundle branch block is present with the characteristic RSR' pattern evident in V1-V3. Multiple criteria for left anterior fascicular block are also fulfilled: 1) qR complexes in I, aVL, 2) rS complexes in II, III, and aVF, 3) widened QRS @ 118 ms, 4) increased QRS voltage in limb leads. This patient later progressed to complete heart block necessitating dual-chamber pacemaker insertion.

Cardiac Resynchronization Therapy Defibrillator Upgrade in Patient with Complete Heart Block and Systolic Heart Failure

by: Matthew T. Brown, MD; Mary M. Pelling, BSE

A patient with complete heart block and systolic heart failure with ejection fraction less than 35% status-post CRT-D upgrade with 100% atrial, 100% bi-ventricular pacing pattern now seen on electrocardiogram. The continuous Lead V1 in the fourth row of the strip shows pacer spikes preceding each atrial and ventricular morphology. It is important to note the QRS is still wide at 182 ms, but more narrow than the 218 ms seen with prior dual-chamber pacemaker. In addition, the left bundle branch block previously seen from isolated right ventricular pacing has now resolved as both ventricles are now paced simultaneously.