Atrial Fibrillation Originating in the Inferior Vena Cava

Figure 1. Holter Monitoring This monitoring shows repetitive premature atrial complexes, some of them not conducted to the ventricle but visible in the upper part of the T-wave (red arrows) and some of them aberrantly conducted. At the bottom, one of the premature atrial complexes (red arrow) is triggering atrial fibrillation.

Figure 2. Baseline Electrocardiogram at the Time of the Ablation Procedure Repetitive premature atrial complexes not conducted to the ventricle are visible on the top of the T-wave similar to the Holter monitoring findings.

Figure 3. Activation Map and Electrograms (Left) Activation map showing the earliest activation at the posteromedial aspect of the inferior vena cava (IVC). (Right) Electrograms recorded from the steerable mapping catheter and the ablation catheter at the earliest activation site before radiofrequency ablation. CS = coronary sinus; SVC = superior vena cava.

Figure 4. Radiofrequency Application Radiofrequency application at the earliest activation point immediately terminated the bigeminated premature atrial complexes, and sinus rhythm was restored. Abbreviations as in Figure 3.

Figure 5. Voltage Map of the Septal and Posterior Aspect of the IVC Before and After Ablation The voltage map on the left side shows a low-voltage area in the posteromedial inferior vena cava (IVC). The voltage map on the right side was generated after ablation and shows homogenization of this area. Intracardiac recordings during pacing from the steerable mapping catheter show local capture at PA 19-20 not conducted to the atrium and demonstrating electrical isolation of the ablated area (arrows). N/A = not applicable; other abbreviations as in Figure 3.