Impact of radiocontrast use during left ventricular pacemaker lead implantation for cardiac resynchronization therapy.

AIMS: The risk of contrast-induced nephropathy (CIN) with radiocontrast use during left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT) is unknown. It is unclear as to whether minimizing contrast use impacts adequacy of LV lead placement. METHODS AND RESULTS: A retrospective analysis was performed of all LV leads placed for CRT at Mayo Clinic, Rochester, MN from 16 March 2001 to 1 April 2009. The primary goal was to assess risk of CIN and adequacy of lead placement depending on the amount of contrast administered during CRT placement. Contrast-induced nephropathy was defined as a ≥25% increase in serum creatinine ≥48 h post-procedurally. Adequacy of lead placement was assessed in a blinded fashion by review of procedural fluoroscopic and post-procedural radiographic images. Eight hundred and twenty-two subjects were divided based on the amount of procedural contrast used into tertile 1 (<55 mL, 257 patients), tertile 2 (55-94 mL, 261 patients), and tertile 3 (≥95 mL, 304 patients). Contrast-induced nephropathy occurred in 5.4% of patients in tertile 1, 5.4% in tertile 2 and 11.8% in tertile 3 (P = 0.004). Among the tertiles, lead positioning was optimal in 95, 80 and 66%, respectively (P < 0.0001). Fluoroscopic time was 34 ± 23, 42 ± 26, and 48 ± 30 min in tertiles 1, 2, and 3 (P < 0.0001). CONCLUSION: Risk of CIN with CRT implantations was substantial. Increased volume of radiocontrast used for LV lead placement was associated with substantially increased risk of CIN. Minimal contrast use was associated with decreased procedural times without adverse impact on adequacy of lead placement.

The autonomic ether: emerging electrophysiologic associations.

As a result of large, multicenter trials supporting ICDs for prevention of sudden cardiac arrest, there has been an exponential increase in ICD device therapy. Cardiologists and general practitioners are increasingly faced with the challenge to evaluate and troubleshoot device problems. In this review, we provide an overview of basic ICD function and malfunction and show examples of common ICD problems and troubleshooting.

Correlative anatomy for the electrophysiologist: ablation for atrial fibrillation. Part II: regional anatomy of the atria and relevance to damage of adjacent structures during AF ablation.

Ablation procedures for atrial fibrillation have become an established and increasingly used option for managing patients with symptomatic arrhythmia. The anatomic structures relevant to the pathogenesis of atrial fibrillation and ablation procedures are varied and include the pulmonary veins, other thoracic veins, the left atrial myocardium, and autonomic ganglia. Exact regional anatomic knowledge of these structures is essential to allow correlation with fluoroscopy and electrograms and, importantly, to avoid complications from damage of adjacent structures within the chest. We present this information as a series of 2 articles. In a prior issue, we have discussed the thoracic vein anatomy relevant to paroxysmal atrial fibrillation. In the present article, we focus on the atria themselves, the autonomic ganglia, and anatomic issues relevant for minimizing complications during atrial fibrillation ablation.

Correlative anatomy for the electrophysiologist: ablation for atrial fibrillation. Part I: pulmonary vein ostia, superior vena cava, vein of Marshall.

Ablation procedures for atrial fibrillation (AF) have become an established and increasingly used option for managing patients with symptomatic arrhythmia. The anatomic structures relevant to the pathogenesis of AF and ablation procedures are varied and include the pulmonary veins (PVs), other thoracic veins, the left atrial myocardium, and autonomic ganglia. Exact regional anatomic knowledge of these structures is essential to allow correlation with fluoroscopy and electrograms, and, importantly, to avoid complications from damage of adjacent structures within the chest. We have presented this information in a 2-part series. In the present article, we examine the general anatomic characteristics of the PVs, superior vena cava, and vein of Marshall. Features of particular relevance for the invasive electrophysiologist are pointed out. In a subsequent article, we discuss the regional anatomy of the left and right atria and anatomic considerations in preventing complications during AF ablation.

Relevance of endocavitary structures in ablation procedures for ventricular tachycardia.

BACKGROUND: Radiofrequency (RF) ablation for ventricular tachycardia (VT) has high failure rates. Whether endocavitary structures (ECS) such as the papillary muscles (PMs), moderator bands (MBs), or false tendons (FTs) impact VT ablation is unknown. METHODS AND RESULTS: We retrospectively reviewed records of 190 consecutive patients presenting for VT ablation and identified 46 (24%) where ECS affected ablation. In 31 of 46 patients (67%), the ECS created difficulty with catheter manipulation (n = 20), interpretation of pace map data (n = 7), or with accurately defining a scar (n = 4). In 15 of 46 (33%), specific mapping and RF energy delivery targeting the ECS itself was necessary to eliminate the arrhythmia. Detailed electroanatomic mapping was performed in 11 of 15 (73%), noncontact mapping in 3 of 15 (20%), multielectrode catheter mapping in 1 of 15 (7%), and intracardiac ultrasound in 14 of 15 (93%) patients. The ablated ECS was a PM in 5 of 15, the MB in 7 of 15, and an FT in 3 of 15. The arrhythmogenic substrate on the ECS was a focus of automatic tachycardia in 9 of 15 and the slow zone responsible for reentrant arrhythmia in the remaining 6 of 15. Successful elimination of tachycardia without recurrence was obtained in all 15 cases. There was no evidence of valvular damage or disruption of the valvular apparatus. CONCLUSION: During VT ablation procedures, ECS should be considered for specific mapping and targeted ablation. Once recognized, these structures can be successfully targeted for ablation without valve damage.

The Pericardial Space: Obtaining Access and an Approach to Fluoroscopic Anatomy.

The pericardial space is now increasingly used as a means and vantage point for mapping and ablating various arrhythmias. In this review, present techniques to access the pericardial space are examined and potential improvements over this technique discussed. The authors then examine in detail the regional anatomy of the pericardial space relevant to the major arrhythmias treated in contemporary electrophysiology. In each of these sections, emphasis is placed on anatomic fluoroscopic correlation and avoiding complications that may result.

Anticoagulation During AF Ablation: The Balance between Thromboembolism and Bleeding.

Radiofrequency ablation for atrial fibrillation is being increasingly used to treat patients with symptomatic arrhythmia. The procedure is complex and associated with significant complications including thromboembolism, stroke, and bleeding. Despite significant advances in catheter design, online cardiac imaging, and greater operator experience, both stroke and major vascular complications continue to be problematic. Increasing the duration and intensity of anticoagulation has been the primary modality used to decrease thromboembolism. However, these measures increase the likelihood and severity of bleeding-related complications. The optimal method of anticoagulation along with the adjunctive use of technology to decrease vascular complications and mechanically prevent cerebral embolization is unknown. In this paper, we review the present methods used by ablationists to decrease the likelihood of thromboembolism during atrial fibrillation. We then describe methods used to decrease bleeding and vascular complications at access sites as well as cardiac perforation. We briefly discuss newer techniques to decrease endovascular complications including epicardial ablation and the use of temporarily implanted vascular protection devices.Finally, we describe the best option or combination of approaches that attempt to balance the risks of thromboembolism and bleeding during AF ablation..

The Phrenic Nerve And Atrial Fibrillation Ablation Procedures.

Radiofrequency ablation is increasingly used as an option to optimally manage patients with symptomatic atrial fibrillation. Presently, ablationists strive to improve success rates, particularly with persistent atrial fibrillation, while simultaneously attempting to reduce complications. A well-recognized complication with atrial fibrillation ablation is injury to the phrenic nerve giving rise to diaphragmatic paresis and patient discomfort.Phrenic nerve damage may occur when performing common components of atrial fibrillation ablation including pulmonary and superior vena caval isolation. The challenge for ablationists is to successfully target the arrhythmogenic substrate while avoiding this complication. In order to do this, a thorough knowledge of phrenic nerve anatomy, points in the ablation procedure where nerve damage is more likely, and an understanding of the presently utilized techniques to avoid this complication is required. In addition, when this complication does arise, prompt recognition of its occurrence, knowledge of the natural history, and available methods for management are needed.In this review, we discuss the underlying anatomic principles, techniques of avoiding phrenic nerve damage, and presently available methods of diagnosing and managing this complication.