Asirvatham, Samuel J.

Ablation and Mapping of the Conus Papillary MuscleCatheter ablation is an increasingly used and successful treatment choice for right ventricular outflow tract (RVOT) arrhythmias. While the role of endocavitary structures and the regional morphology of the ventricular inflow tract and the right atrium as a cause for difficulty with successful ablation are well described, similar issues within the RVOT are not well understood. It is also not commonly appreciated that one of the papillary muscles is located within the proximal RVOT. We report 3 patients in which ventricular arrhythmia was targeted and ablated in the conus papillary muscle. The anatomic features, potential role of the fascicular conduction system, and unique challenges with mapping arrhythmia arising from this structure are discussed.

Introduction Lateral or posteriolateral coronary vein has been considered the optimal location of left ventricular (LV) lead placement for cardiac resynchronisation therapy (CRT). However, the long-term clinical outcomes of CRT based on LV lead location have not been sufficiently addressed. Methods Seven hundred and eighteen CRT-P/CRT-D recipients from Jan 2002 to Dec 2008 were studied. At the CRT implant, the LV lead placement was prioritised as posterolateral/lateral (PL, 50%), anterior lateral (AL, 31%), anterior interventricular (AI, 12%) or middle cardiac veins (MC, 7%). NYHA class and echocardiography were assessed before and after CRT. Clinical outcomes of CRT were compared among 4 LV lead locations. Results Patient baseline demographics, except the gender (P=0.03), were similar among four groups. After CRT, the improvement in NYHA class, LV ejection fraction (EF), and LV diastolic diameter were significantly improved comparably across four LV lead locations (table). The increase in LVEF by >5% were 46%, 47%, 41% and 42% in PL, AL, AI and MC groups (p=0.87). Conclusion The present study suggests that LV lead positioned in the alternative coronary veins, other than posteriolateral or lateral location, achieve comparable benefit in improvement of HF symptoms, and LV function after CRT. Table Comparison of clinic outcomes before and after CRT in different LV lead locations Lateral vein (N=359) Anterolateral vein (N=226) middle cardiac vein (N=49) anterior interventricular vein (N=84) Pre-CRT Post-CRT Pre-CRT Post-CRT Pre-CRT Post-CRT Pre-CRT Post-CRT NYHA 3.02±0.46 2.34±0.81* 2.92±0.53 2.34±0.89* 3.10±0.45 2.70±0.85* 2.98±0.52 2.43±0.86* LVEF (%) 23.57±7.28 30.82±11.67* 24.19±7.96 30.44±12.06* 24.97±7.62 30.72±11.43* 22.45±7.25 28.40±11.73* LVEDD (mm) 65.71±9.12 63.00±9.73* 65.79±8.87 63.88±9.88* 65.39±9.32 62.61±10.25* 68.48±8.92 64.86±9.67* LVESD (mm) 57.91±9.89 52.83±11.68* 56.69±10.23 53.03±12.01* 56.18±11.56 52.24±13.11* 59.09±10.04 55.32±13.30 RVD (mm) 0.90±0.86 0.82±0.85 0.85±0.92 0.82±0.85 0.86±0.83 1.01±0.84 0.56±0.77 0.78±0.91 RV dysfunction 1.05±0.92 0.88±0.92* 1.03±0.93 0.93±0.91 1.06±0.97 1.06±0.90 0.74±0.86 0.79±0.96 MR (m/s) 1.54±0.78 1.30±0.75* 1.57±0.83 1.35±0.75* 1.53±0.71 1.15±0.70* 1.36±0.69 1.19±0.68 * P<0.05 compared to pre-CRT.

Background— A patent foramen ovale (PFO) may permit arterial embolization of thrombi that accumulate on the leads of cardiac implantable electronic devices in the right-sided cardiac chambers. We sought to determine whether a PFO increases the risk of stroke/transient ischemic attack (TIA) in patients with endocardial leads. Methods and Results— We retrospectively evaluated all patients who had endocardial leads implanted between January 1, 2000, and October 25, 2010, at Mayo Clinic Rochester. Echocardiography was used to establish definite PFO and non-PFO cohorts. The primary end point of stroke/TIA consistent with a cardioembolic etiology and the secondary end point of mortality during postimplantation follow-up were compared in PFO versus non-PFO patients with the use of Cox proportional hazards models. We analyzed 6075 patients (364 with PFO) followed for a mean 4.7±3.1 years. The primary end point of stroke/TIA was met in 30/364 (8.2%) PFO versus 117/5711 (2.0%) non-PFO patients (hazard ratio, 3.49; 95% confidence interval, 2.33–5.25; P <0.0001). The association of PFO with stroke/TIA remained significant after multivariable adjustment for age, sex, history of stroke/TIA, atrial fibrillation, and baseline aspirin/warfarin use (hazard ratio, 3.30; 95% confidence interval, 2.19–4.96; P <0.0001). There was no significant difference in all-cause mortality between PFO and non-PFO patients (hazard ratio, 0.91; 95% confidence interval, 0.77–1.07; P =0.25). Conclusions— In patients with endocardial leads, the presence of a PFO on routine echocardiography is associated with a substantially increased risk of embolic stroke/TIA. This finding suggests a role of screening for PFOs in patients who require cardiac implantable electronic devices; if a PFO is detected, PFO closure, anticoagulation, or nonvascular lead placement may be considered.

Coronary Artery Ventricular Tachycardia. Background The coronary cusps have been well described as a successful site for ablation in patients with symptomatic outflow tract ventricular tachycardia. The earliest site of activation is rarely found at the ostia or into the main coronary arteries. The exact anatomic substrate, diagnostic characteristics, and therapeutic approaches for such instances are poorly understood. Methods We retrospectively reviewed outflow tract ventricular arrhythmia (OTVA) ablations done at Mayo Clinic Rochester from 2003 to 2011 (total VT: 414; outflow tract VT: 106). Three cases were identified where the earliest site of activation was not within the cusp but rather at or within the coronary ostia (3/414 for all VT: 0.7%; 3/106 for all OTVT: 2.8%). Results In 1 patient, the left main coronary artery (LMCA) was found to have electrograms (EGMs) recorded with bipolar mapping that preceded activation in the cusps or the left ventricular outflow tract. In 2 cases, the right coronary ostium and proximal right coronary artery recorded the earliest signals. Intracardiac echocardiographic guidance was used to successfully ablate these arrhythmias targeting the aortic route (1 patient) or the right coronary cusp (2 patients), and essentially isolated the focus of origin from the ventricular outflow tracts. Detailed mapping of surrounding structures, including the atrial appendages, the contralateral outflow tract, and the coronary venous system excluded far‐field mapping in the artery as a cause for early activation at the ostial location. Local EGM characteristics suggested an unusually lengthy supravalvar myocardial extension as the likely arrhythmogenic substrate. Ablation was successful without coronary arterial or valvular injury and without valvular or root stenosis. Conclusions Endocardial ablation isolating foci of origin in the vicinity of the coronary ostia is a challenging procedure but can be performed safely with appropriate visualization and is effective in the treatment of OTVA.

BackgroundRecent studies have shown that magnetic resonance imaging (MRI) of patients with pacemakers can be safely performed under careful monitoring, but they excluded patients with recently implanted devices. Patients with recent implants may be at a greater risk for complications during MRI imaging due to lack of lead and wound maturity.MethodsWe implemented a clinical protocol for MRI imaging of patients with implanted cardiac devices, and prospectively collected data. For this study, we retrospectively analyzed two groups of patients: those with recently implanted (≤42 days) and nonrecently implanted (>42 days) leads at the time of MRI scanning. All devices were interrogated before and after scanning, and were reprogrammed during the scan as per protocol.ResultsOf the 219 scans (in 171 patients), eight included patients with recently implanted (range: 7–36 days) and 211 with only nonrecently implanted pacemaker leads. During the scan, there were no complications in the early or late group. In one patient imaged 79 days postimplant, frequent premature ventricular complexes were noted during the scan, requiring no action. No patient reported pain during or immediately after the procedure. No clinically significant changes in function were seen at subsequent follow up (average 104 days post‐MRI). Compared to patients with nonrecently implanted leads, there was no difference in any parameter between the two groups.ConclusionsWith a strong clinical indication and with careful monitoring, MRI imaging is feasible in patients with recently implanted pacemakers, although experience is limited.

BackgroundPatients with preexisting mild cognitive impairment or dementia may be at increased risk for developing cardiac device complications due to an impaired ability to follow postimplant care instructions. We sought to determine whether rates of infection, lead dislodgement, or appropriate or inappropriate implantable cardioverter defibrillator (ICD) shocks are increased in this population.MethodsMedical charts of 561 patients with mild cognitive impairment or dementia who underwent pacemaker (PM) or ICD implantation between January 2002 and October 2009 at Mayo Clinic were identified. A total of 134 patients who were diagnosed with cognitive impairment or dementia before device implantation or within 1 year of implantation were compared with 134 matched controls. Information was collected on patient characteristics, comorbid medical conditions, ejection fraction, complications, device type, device therapy, and mortality. Device information was prospectively entered into a database and retrospectively reviewed.ResultsOf the 134 patients with mild cognitive impairment and dementia, 99 underwent PM implantation and 35 underwent ICD implantation. Compared to controls, there was no difference in patient characteristics, ejection fraction, or comorbidities except for diabetes, which was more prevalent in the cognitively impaired and demented group (18.7% vs 30.6%, P = 0.02). There was no difference in device therapy and complications (14.4% vs 5.8%, P = 0.268). However, there was a decreased survival in patients with cognitive impairment and dementia when compared to the control group (42% vs 67% at 5 years, P = 0.007).ConclusionPatients with cognitive impairment and standard device indications are not at increased risk for device complications and therapy but their survival is much lower than in matched controls. The cause of this lower survival is unknown but may be related to the underlying neurological disease. Presence of cognitive impairment should therefore be considered when contemplating implantation of a cardiac device.