Proximal coronary sinus pacing induced prolonged asystole.

Figures

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  Figure 1. Left-anterior oblique (LAO) and right-anterior oblique (RAO) fluoroscopic views of catheter locations, including the decapolar catheter in the coronary sinus (CS), an ablation catheter at the His bundle (HB) region, and two quadripolar catheters in the right atrium (RA) and right ventricle (RV); as shown in the fluoroscopic views, the region of the HB recording is extended inferiorly toward the CS ostium.

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  Figure 2. A) Normal baseline intracardiac intervals [atrial-His bundle (AH), His-ventricular (HV)]; B) Extrastimulation from the high right atrium (HRA) catheter leading to one to one antegrade conduction even with a premature cycle length (CL) of 280 ms

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  Figure 3. A) Atrial-His bundle (AH) prolongation after stopping the proximal coronary sinus (CS) stimulation with the cycle length (CL) of 290 ms; B) Atrial flutter (AFL) with the atrial CL of 180 ms and 2:1 atrioventricular (AV) ratio

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  Figure 4. A and B) Prolonged ventricular asystole during proximal coronary sinus (CS) overdrive pacing with the cycle length (CL) of 180 ms; C) Atrioventricular (AV) nodal conduction suppressed again by proximal CS overdrive pacing without atrial capturing

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  Figure 5. A) Proximal coronary sinus (CS) stimulation at the cycle length (CL) of 210 ms, while the patient being in atrial fibrillation (AF) rhythm associated with ventricular pauses; B) Distal CS pacing at the CL of 180 ms not resulting in atrioventricular (AV) nodal suppression, unlike proximal CS stimulation