Faculty Bibliography

BACKGROUND: Atrial fibrillation catheter ablation is frequently guided by identification of fractionated electrograms, which are thought to be critical for maintenance of the arrhythmia. Objective automated means for identifying fractionation independent of physician interpretation have not been standardized or validated. OBJECTIVE: The purpose of this study was to standardize and validate an automated algorithm to rapidly identify fractionated electrograms for high-density atrial fibrillation fractionation mapping. METHODS: Left and right atrial fractionation maps were generated by EnSite NavX 6.0 software, using standardized ablation catheters in eight patients with atrial fibrillation. Two blinded electrophysiologists interpreted all electrograms as either fractionated or not fractionated. A stepwise approach was used to optimize automated settings to accurately identify fractionation. High-density fractionation maps were generated with a 20-pole mapping catheter in eight other patients. Two blinded electrophysiologists interpreted all electrograms as near field or far field. The algorithm was refined to optimize settings to exclude far-field signals and retain near-field signals. The sampling segment length was adjusted to optimize recording time to ensure reproducibility. RESULTS: Using 1,514 points, the automated software achieved sensitivity of 0.75 and specificity of 0.80 for identification of fractionated electrograms. Using 725 points collected via multipole catheters with optimal automated settings, 94% of near-field fractionated electrograms were accurately identified. A 6-second sampling length was needed for reproducible fractionation measurements. CONCLUSION: Standardized settings of EnSite NavX 6.0 software with 6-second data collection per point can rapidly and accurately generate high-density fractionation maps independent of physician electrogram interpretation. This may allow for an automated, standardized approach to atrial fibrillation fractionated ablation

This study assessed the effect of transtricuspid placement of permanent pacemaker (PPM) and implantable cardioverter defibrillator (ICD) leads on tricuspid regurgitation (TR) in 248 patients with echocardiograms before and after placement. Some 21.2% of patients with baseline mild TR or less developed abnormal TR (3.4% mild-moderate, 12.8% moderate, 1.1% moderate-severe, 3.9% severe) after implant. TR worsened by 1 grade or more after implant in 24.2% (20.7% of PPMs vs. 32.4% of ICDs; P < .05). TR worsening was more common with ICDs than PPMs in patients with baseline mild TR or less. After lead implantation, abnormal TR developed in 21.2% and severe TR developed in 3.9% of patients with initially normal TR. TR worsened by at least 1 grade in 24.2%. Patients with ICDs had a higher rate of TR worsening compared with patients with PPMs (32.4% vs. 20.1%; P < .05)

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