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Atrial Fibrillation, Total Atrioventricular Block and Right Bundle-Branch Block Morphology
Escape Rhythm: Chaotic Electrical Activity, Impenetrable Barrier and Failsafe
Raymond Pranata1, Abraham Fatah1, Wendy Wiharja1, Sunanto Ng2
1
Faculty of Medicine, University Pelita Harapan, Tangerang, Indonesia
2
Department of Cardiology and Vascular Medicine, Siloam Hospital Lippo Village, Tangerang, Indonesia
INTRODUCTION
Chaotic electrical activity in atrial fibrillation (AF) is conducted to ventricle and may results
in rapid ventricular response. Total atrioventricular block (TAVB) prevents atrial impulse
from being conducted to ventricle. Our aim is to present a case with recurrent TAVB and
atrial fibrillation in patient with 3VD and CKD who refused further stenting and CABG.
CASE REPORT
71 y.o male presented with dyspnea since 4 hours before admission and syncope, the patient
was conscious on ER. Angina (-), edema (-). PMH of 3-vessel disease, patient refused bypass
surgery and was stented twice. AF treated with warfarin, hypertension and CHF. BP 100/60,
HR 43x/minute. Pulmonary examination was within normal limits. ECG revealed AF, TAVB
and ventricular escape rhythm with right bundle-branch block morphology. Patient was
anemic, with eGFR of 21.2, INR 2.13, Potassium of 6.8 and hsTroponin 28.5 pg/mL.
Previous angiography revealed 100% occlusion of RCA with collaterals, 30-40% in left main,
100% occlusion in LAD and 80% stenosis in mid LCx. Patient was diagnosed with TAVB,
AF, 3-vessel disease, chronic kidney disease stage 4 and CHF. Patient was scheduled for
permanent pacemaker (PPM) implantation.
DISCUSSION
Ischemia and heart failure predispose patient to AF. Ischemia is the possible etiology of
TAVB. AF usually requires rate control, however it is not of concern because of the
concurrent TAVB, which does not allow atrial impulse to pass. Anticoagulation is still
necessary to prevent thromboembolism. Relying on heart’s failsafe mechanism, the
ventricular escape rhythm becomes the ventricle’s pacemaker. It is unfortunately, inadequate
and mandates PPM implantation which is indicated in TAVB. Ideal treatment for this patient
is revascularization, however it is limited by patient’s refusal and kidney function, PPM is
considered. Ventricular pacing by PPM will increase cardiac output, ease symptoms and
improve quality of life although atrial contribution to cardiac output won’t be recovered and
ischemic symptoms will still manifest. This condition is similar to those AF patients who
were treated with ‘pace and ablate’ method.
CONCLUSION
At first, PPM implantation in atrial fibrillation might sounds counter-intuitive. However, a
blend of chaotic electrical activity, impenetrable barrier and failsafe mechanism requires a
more methodical approach.
Keywords: Bradycardia, AV block, Atrial fibrillation, Pacemaker, Escape rhythm