John D. Fisher

Asymptomatic Anterior Perforation of an ICD Lead into Subcutaneous Tissues

A 71‐year‐old woman underwent routine impantable cardioverter defibrillator implantation. On a predischarge check the next day, electrical signals and thresholds were excellent and similar to those at implant. The chest X‐ray was unremarkable and showed good lead position at the right ventricular apex (RVA). At a routine one‐month postimplant visit, electrograms were found to be miniscule, and pacing could not be achieved. Chest X‐ray and fluoroscopy suggested perforation, then this was confirmed by computed tomography scan. The tip of the lead was estimated to be within 7 mm of the surface of the skin. The system was removed surgically, and the patient continued to do well.

Prognostic Significance of Nonsustained Ventricular Tachycardia Identified Postoperatively After Coronary Artery Bypass Surgery in Patients with Left Ventricular Dysfunction

Post‐CABG Nonsustained VT. Introduction: Nonsustained ventricular tachycardia (NSVT) occurs frequently in the postoperative period (≤30 days) after coronary artery bypass graft (CABG) surgery, a setting where many factors may play a role in its genesis. The prognosis of NSVT in this setting in patients with left ventricular (LV) dysfunction is unknown. This study was designed to assess its significance.

The psychological impact of implantable cardioverter-defibrillator recalls and the durable positive effects of counseling.

Background: It is known that patients with lifesaving devices such as implantable cardioverter‐defibrillators (ICDs) may be alarmed and worried by recalls or alerts related to their ICDs.

Relative and absolute benefits: main results should be reported in absolute terms.

Conventions change in scientific writing. Many years ago, it was usual to report clinical data as mean ± SEM (standard error of the mean). This produced impressively small “error bars” in graphic representations, but were often misleading, especially when dealing with small sample sizes. Most journals therefore urged a change to standard deviation (± SD), which has almost entirely replaced SEM in clinical reports. In the arrhythmia field, early implantable cardioverter defibrillator (ICD) papers reported “hypothetical” deaths and “hypothetical arrhythmic deaths” based on the assumption that an ICD shock could be equated with a life saved.1 These terms fail to withstand scrutiny. A NASPE (HRS) position paper2 called for primary endpoints to be reported as total mortality (“dead or alive”), and this is now standard practice. It is now time for another change in convention. Clarity demands that differences in outcomes should be reported primarily in absolute rather than relative terms. Furthermore, the number needed to treat (NNT) to save a life (or achieve some other defined benefit) over a specified timeframe should be reported. Let us review some points.

Defibrillation testing: philosophy and science.

In this issue of PACE, Sauer et al.1 revisit the issue of defibrillation testing (DFT) in implantable cardioverter defibrillators (ICDs), with the twist of testing during long-term follow-up. Readers should note that all patients included in this series had DFT margins > 10 J twice or 5 J three times at initial implant, and then routinely underwent retesting at 3 months and then annually. The authors found that modern systems did very well at follow-up, and that patients could be identified as higher risk of device failure by the identification of R-waves < 7.0 mV, or a DFT margin of 5J. There are some surprises. In this series, “there were no component failures (ICD lead fracture or generator malfunction) in systems implanted after 2003 (0% vs 1.3%; P > 0.01).” This is remarkable, because the mid 2000s were notable for multiple alerts (“recalls”) and few large centers escaped the problem. The authors state that it may be “impractical for most centers to perform routine serial ICD testing on every patient due to time and resource constraints.” DFT testing is typically a quick and noninvasive process. Perhaps the authors would find it congenial to limit repeat DFT testing to the time of pulse generator replacement or if there is a clinical change that could affect DFTs. Concerns are expressed that “routine defibrillation testing may not warrant the cost and potentially lethal risk involved.” It is reassuring that the authors encountered only “three mi-

Rate responsive pacemakers: a rapid assessment protocol.

Background: Rate responsive (RR) pacemakers are commonly implanted with nominal conservative factory‐set responsiveness, which is usually accepted because established exercise protocols are time‐consuming. We aimed for efficient assessment of RR pacemaker settings.

Posterior septal and right free-wall Kent pathways visualized in situ and removed at operation.

Abstract This article describes the first posterior septal and first and second right free‐wall pathways Identified at operation for Wolff‐Parkinson‐White syndrome and confirmed histologically. All pathways were found in the areas of preexcitation identified by pre and intraoperative mapping. They bridged the atrium and ventricle, and postoperative electrophysiological testing confirmed division of the pathways. Kent bundles may be identified at the time of surgery but they appear to be gossamer structures usually destroyed during surgical manipulation of the coronary sulcus. Visualization of the suspected bypass tract should not alter or limit the extent of surgical dissection.

Is the twist hazardous to your health

Active fixation leads have several advantages. The leads can be placed in a larger selection of endocardial locations or sites. Once fixed (screwed) in place, the lead is relatively resistant to displacement during positioning of additional leads. If extraction is required after long-term implantation, active fixation leads are somewhat easier to remove. Because of these advantages, active fixation leads have increasingly come to dominate the field. For one company, the ratio of active to passive leads was 0.7 in FY 2000, and 3.4 in FY 2006.1 Nevertheless active fixation leads have their own problems, as we are reminded by Geyfman and colleagues in this issue of PACE.2 Geyfman et al.2 report three cases of perforation and pericardial tamponade associated with active fixation leads. The effusions/tamponades were attributed to the mechanical effects of the screw helix on surrounding tissues after it perforated beyond the epicardium. Greyfman et al. join previous authors3–5 who have cautioned against widespread or routine use of active fixation leads. It should be noted that perforation does not equate with effusion, tamponade or indeed with any clinical problem. In a recent report from our institution coauthored by one of us (JNG), 100 consecutive CT scans were analyzed and asymptomatic perforations were identified in 15.6 Active fixation and passive fixation leads were equally involved in these asymptomatic patients. In the atrium, passive fixation leads had an insignificantly greater chance of perforation (3/12 vs 6/49). One of the lessons that implanters can learn is that some of the additional capabilities that active fixation leads provide may result in untoward consequences. The illustration in the Geyfman article shows an atrial lead positioned laterally. This would not be a viable location for a passive fixation lead, but an active fixation lead is easy to place in this position. Nonetheless, the very thin atrial

AVNRT ablation: aiming for 100/0, and for comfort!

In this issue of PACE,1 Chan and colleagues compare radiofrequency (RF) and cryo ablation for atrioventricular nodal reentry tachycardia (AVNRT) ablation. The authors draw attention to the stresses on both the patient and on the operator. They conclude that operator stress is higher with RF than cryo, probably because of the need for intensive and continuous and simultaneous monitoring of catheter position, electrograms, electrocardiograms, and ablation settings. As the authors point out, it is difficult to achieve 100% “cure” of AVNRT or 0% atrioventricular block (AVB). Some of the challenges are anatomical. Patients with “short septums” (between the His area and the coronary sinus os) may offer little room for error in catheter position, and sudden deep breath or other cause for catheter movement can have serious consequences. One of the advantages here of cryo is that the lead tends to become stuck in place at lower temperatures (–60◦C–80◦C) so that inadvertent movement is less of a problem. It is also known that a small percentage of patients will have both the fast and slow pathways well posterior to the His position; hence, the suggestion by some that anterograde and retrograde septal

Paul A. Levine, M.D.

Paul A. Levine passed away peacefully on December 27, 2015, surrounded by his family, after an illness that lasted through most of 2015. He had entered hospice only a few days earlier, and died surrounded by his wife and others he loved. For many years, Paul served as the Device Rounds editor for Pacing and Clinical Electrophysiology. Part of his unique talent was choosing just the right reviewers for any given paper. Few were his equals when it came to understanding and teaching the subtleties of pacemaker timing cycles, “hidden features,” and potential implications. Although Paul spent many years working with Pacesetters/St. Jude Medical, his knowledge extended to all manufacturers. Paul’s