Faculty Bibliography

BACKGROUND: Ultrasound evaluation of the abdominal aorta and its branches is usually performed transabdominally. Not infrequently, the image quality is suboptimal. Recently, an intracardiac echocardiography probe has become commercially available. These probes are usually inserted intravenously and advanced to the right heart for diagnostic and monitoring purposes during procedures such as atrial septal defect closure and pulmonary vein isolation. Because of the close anatomic relation between the abdominal aorta and the inferior vena cava, we hypothesized that these probes would be useful in the evaluation of the abdominal aorta and the renal arteries. METHODS: Sixteen patients with normal renal function and no history of hypertension who were undergoing a pulmonary vein isolation procedure or atrial septal defect closure were studied. In each patient, the intracardiac echocardiography probe was inserted in the femoral vein and advanced to the right atrium for the evaluation of the left atrium and the pulmonary veins during the procedure. At the end of the therapeutic procedure, the probe was withdrawn into the inferior vena cava for the evaluation of the aorta and renal arteries. RESULTS: High-resolution images of the abdominal aorta from the diaphragm to its bifurcation were easily obtained in all patients. These images allowed for the evaluation of arterial size, shape, and blood flow. Both renal arteries were easily visualized in each patient. With the probe in the inferior vena cava, both renal arteries were parallel to the imaging plane and, therefore, accurate measurement of renal blood flow velocity and individual renal blood flow were measured

A 21-year-old woman presented with a pacemaker-associated superior vena cava (SVC) syndrome refractory to medical therapy. In the past, treatment of this condition has involved surgical exploration which is invasive. With the evolution of percutaneous techniques, treatment has included venoplasty and stenting over the pacemaker lead. There is limited experience with a more advanced percutaneous technique in which the lead is extracted by an excimer laser sheath. The extraction is immediately followed by venoplasty and stenting at the site of stenosis with subsequent implantation of a new permanent pacemaker at the previously occluded access site. The patient underwent this procedure which proved to be safe, minimally invasive, and an efficient method of treating SVC syndrome secondary to a single chamber atrial pacemaker

Performance of a New Cardiac Cryoablation System in the Treatment of Cavotricuspid Valve Isthmus-Dependent Atrial Flutter. We sought to evaluate prospectively the safety and efficacy of cryothermal energy to ablate typical atrial flutter (AFL). Ablation of cardiac tissue using cryothermal energy has recently been developed as an alternative to radiofrequency energy, which may offer certain advantages in the treatment of AFL. This prospective, multicenter nonrandomized study of a new catheter-based system for the treatment of cavotricuspid isthmus (CTI)-dependent AFL enrolled patients between 18 and 75 years of age. The CTI dependence of AFL was confirmed at electrophysiologic study with activation mapping and/or entrainment. Patients with atrial septal defect, recent myocardial infarction, left ventricular ejection fraction <0.30, or prior AFL ablation were excluded. Cryoablation of AFL was performed in 48 patients from 11 centers. The procedure was immediately successful in 45 patients (94%), and effective in 30 of 40 patients with complete data available at 6 months. Cryoablation is a promising new treatment of CTI-dependent AFL refractory to medical therapy. Further improvements in catheter design and intravascular sheaths will be tested in a larger multicenter trial

BACKGROUND: Typical atrial flutter (AFL) is a macroreentrant arrhythmia characterized by a counterclockwise circuit that passes through the cavotricuspid isthmus with passive depolarization of the left atrium. These electrical events are thought to be responsible for the classic 'sawtooth' wave of atrial flutter seen on the surface electrocardiogram characterized by a gradual downward deflection followed by a sharp negative deflection. It has been suggested that the negative flutter wave is a result of passive depolarization of the left atrium. We hypothesized that interruption of the circuit within the isthmus would prevent the reentrant wave from depolarizing the left atrium thus eliminating the component of the electrocardiogram reflecting left atrial depolarization. METHODS: We examined 100 cases of atrial flutter with the typical 'sawtooth' pattern referred for radiofrequency ablation. Ninety-seven of the 100 were successfully ablated. All cases were reviewed for termination of atrial flutter with the last intracardiac electrogram just lateral to the site of linear ablation and surface flutter wave at the moment of termination not obscured by the QRS segment or the T-wave. Seventeen of the 97 met these criteria. RESULTS: Seventeen of the 17 cases demonstrated a gradual negative deflection as the last discernible wave of atrial activity followed by an isoelectric period and resumption of normal sinus rhythm. The last generated wave lacked the sharp negative downstroke. CONCLUSION: These results suggest that the sharp negative deflection of flutter waves likely correlates with the wavefront's penetration of the interatrial septum and passive depolarization of the left atrium

The purpose of this study was to evaluate the safety and efficacy of radiofrequency (RF) ablation of typical atrial flutter by using an 8-mm electrode catheter and a 100-W RF power generator. A limitation of previous trials of catheter ablation of atrial flutter is that the data were not collected as part of a prospective multicenter clinical trial. The study results associated catheter ablation of typical atrial flutter in a cohort of 150 patients with an 88% acute efficacy rate. At 6-month follow-up, recurrent typical atrial flutter was observed in 13% of patients. Of the 12 patients with typical atrial flutter recurrence, 4 were symptomatic and 8 were asymptomatic. Procedure duration was a significant predictor of typical atrial flutter recurrence. The 12-month rate for development of atrial fibrillation was 30%. Catheter ablation of atrial flutter was associated with significant improvements in 5 of 8 domains of the Short Form 36 Survey (quality of life) and significant decreases in 13 of the 16 symptoms of the Symptom Checklist. The device- or procedure-related complication rate was 2.7%. Skin burns occurred at the dispersive pad site due to stronger RF power in 3 patients. Use of a dual dispersive pad system mitigated this problem. Thus, the results of this study associated catheter ablation of atrial flutter with high acute efficacy, a small risk of recurrent atrial flutter, and an important risk of atrial fibrillation during follow-up.