Author + information
- Received October 8, 2015
- Revision received January 4, 2016
- Accepted January 7, 2016
- Published online August 1, 2016.
- Kashish Goel, MBBS,
- Thomas A. Foley, MD,
- Carole A. Warnes, MD and
- Christopher J. McLeod, MBChB, PhD∗ ()
- Division of Cardiovascular Diseases, Department of Internal Medicine, and the Department of Radiology, Mayo Clinic, Rochester, Minnesota
- ↵∗Reprint requests and correspondence:
Dr. Christopher J. McLeod, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55905.
A 39-year-old woman with complex congenital heart disease presented with refractory atrial arrhythmias unresponsive to multiple antiarrhythmic agents. Her cardiac anatomy included tricuspid atresia with a single left ventricle, severe pulmonary valve stenosis and transposed great arteries, and status post-bidirectional superior vena cava to pulmonary artery shunt with subsequent Fontan completion and a 33-mm St. Jude Medical mechanical atrioventricular (AV) valve replacement (St. Jude Medical, St. Paul, Minnesota). For her atrial arrhythmias, she underwent successful radiofrequency ablation of the culprit clinical atrial flutter. The index arrhythmia was identified to be a macro re-entrant atrial tachycardia revolving clockwise around the AV valve. The prosthetic valve had been positioned in the heart in a more atrial position, thereby excluding atrial myocardium underneath the sewing ring. To achieve bidirectional conduction block across the isthmus, it was necessary to ablate under the sewing ring of the valve. This was performed with an open-irrigated catheter (30 to 60 ml/min), and in the context of initial high impedance (between 135 and 160 Ω), power was slowly up-titrated from 15 to 30 W. An abrupt increase in impedance was not recognized, and an audible steam pop was heard after 65 s of ablation. Fortunately, block was achieved, and no pericardial effusion was recognized using intracardiac echocardiography. At 3-month follow-up, she reported marked symptomatic improvement with no documentation of arrhythmia recurrence. Routine computed tomography (CT) scan identified the presence of a pseudoaneurysm measuring 1.1 × 0.8 × 3.0 cm in the inferior AV groove arising from the basal inferior ventricular wall by a small neck measuring 3 mm (Figure 1A). One edge of the pseudoaneurysm was extremely close to the right coronary artery (Figure 1A) and the other edge opposed to the mechanical AV valve (Figure 1B). The most likely mechanism of pseudoaneurysm formation was the steam pop that occurred at the ablation site (Figure 1C), as there was no pseudoaneurysm on the pre-ablation CT scan (Figure 1D) This type of injury is not uncommon with the use of high-flow irrigation radiofrequency catheters in low-flow areas with high-contact force. Management strategies for the pseudoaneurysm involved percutaneous closure or repeat surgery. This latter option would entail significant risk because of the proximity to the mechanical valve. At 3-month follow-up, repeat CT scan did not show any enlargement or progression of the pseudoaneurysm, and a conservative noninvasive approach was chosen.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received October 8, 2015.
- Revision received January 4, 2016.
- Accepted January 7, 2016.
- American College of Cardiology Foundation