Extract-stent-replace for treatment of upper baffle stenosis with pacing leads after atrial switch procedures for transposition of the great arteries: An approach to avoid "jailing" the lead.

INTRODUCTION: Venous stenosis is a late complication of the atrial switch (Mustard/Senning) procedure seen in patients with transposition of the great arteries ( d-TGA). Many atrial switch patients require cardiac implantable electronic devices (CIEDs) which further increases the incidence of venous stenosis. Stenosis of the superior limb of the systemic venous pathway (SLSVP) in the presence of CIED leads presents a management challenge. We propose a method for navigating SLSVP stenosis in atrial switch patients with CIEDs. METHODS: The pulse generator and leads were removed using standard extraction techniques. Axillary access was retained via existing leads or new access was obtained. The interventional cardiology team, via groin access, performed stent-angioplasty of the stenotic SLSVP. After stent deployment, the axillary access wire was snared from below, guided through the stent, and pulled into a long groin sheath. A sheath was then advanced over the axillary wire and into the groin sheath creating a path for passage of leads through the stent. New leads were advanced through the axillary sheath into the heart. Leads were secured using standard techniques. RESULTS: All patients had a history of d-TGA and prior atrial switch procedures. In each case, there was stenosis of the SLSVP in the setting of a CIED lead. There were no immediate complications and there was no restenosis on follow-up. CONCLUSION: Post-atrial switch patients with CIEDs can develop stenosis of the SLSVP. A collaboration between electrophysiology and interventional cardiology can allow for device extraction, stent-angioplasty, and lead reimplantation to avoid "jailing" the leads.

An automated fractionation mapping algorithm for mapping of scar-based ventricular tachycardia.

BACKGROUND: Mapping and ablation of fractionated electrograms is a common treatment for scar-based ventricular tachycardia (VT). An automated algorithm has been developed for rapid "fractionation mapping." METHODS: Electroanatomic maps from 21 ablation procedures (14 scar-based VT and seven control idiopathic VT/premature ventricular contractions with normal voltage) were retrospectively analyzed using the Ensite Precision fractionation map (fMap; Abbott Laboratories; Abbott Park, IL, USA) algorithm. For each study, voltage maps and 30 fMaps were generated using combinations of parameters: width (5, 10, 20 ms), refractory time (15, 30 ms), sensitivity (0.1, 0.2 mV), and fractionation threshold (2, 3, 5). Parameter sensitivity was assessed by overlap of fractionated areas (fArea) with successful VT ablation sites (defined by entrainment and/or pace mapping). Specificity was assessed by presence of fractionated areas in control patients. RESULTS: Of the 30 fMap parameter sets tested, seven identified >50% of scar-based VT ablation sites, and 26 contained <5 cm2 fractionation on control fMaps. Three combinations of fMap width/refractory/sensitivity/threshold parameters met both of the above criteria, and 20/30/0.1/2 identified the most VT ablation sites (79%) and generated 42.3 ± 28.2 cm2 of fArea on scar-based VT maps compared with 4.9 ± 3.2 cm2 on control maps (P = .001). None of the control patients and 23% of the scar-based VT patients had VT recurrence at mean 15 month follow-up. CONCLUSION: Careful selection of signal processing parameters optimizes sensitivity and specificity of automated fractionation mapping for scar-based VT. Real-time use of fMap algorithms may reduce VT ablation procedure time and improve substrate modification, which may improve outcomes.

Tumor Treating Fields Utilization in a Glioblastoma Patient with a Preexisting Cardiac Pacemaker: The First Reported Case.

BACKGROUND: Tumor-treating fields (TTFs) have become an important, evidence-based modality in the treatment of glioblastoma (GBM). In patients requiring cardiac pacemakers, TTF therapy is complicated by theoretical concerns regarding possible electrical interaction between the devices. CASE DESCRIPTION: A 57-year-old man with past medical history of sick sinus syndrome requiring cardiac pacemaker implantation suffered an acute neurologic change associated with a left parieto-occipital lesion, which was found to be GBM. After completion of guideline-concordant chemoradiation, he chose to undergo TTF therapy. Because of the absence of cardiac symptoms and the theoretical risk of far-field sensing by the pacemaker of the TTF device (potentially resulting in pacemaker inhibition), the pacemaker was turned off before receiving TTF. Following TTF implementation, the patient responded well; he remains alive more than 25 months following his GBM diagnosis, exceeding the median 20.9-month survival of the recently completed phase III TTF randomized clinical trial for newly diagnosed GBM. Furthermore, he has exhibited neither cardiac morbidity nor adverse scalp reactions to TTF therapy. CONCLUSIONS: The first reported case of successful TTF administration in a GBM patient with a previously implanted cardiac pacemaker may allay the concerns of neuro-oncologists, cardiologists, radiation oncologists, and all certified TTF prescribers regarding the applicability of TTF in suitable candidates with preexisting cardiac pacemakers. This case indicates that TTF therapy may be efficacious in patients with indwelling magnetic resonance image-conditional cardiac pacemakers turned to the off position and that physical removal of the pacemaker is not necessary before starting TTF.

Comparative Effectiveness of Interventions for Stroke Prevention in Atrial Fibrillation: A Network Meta-Analysis.

BACKGROUND: The goal of this study was to compare the safety and effectiveness of individual antiembolic interventions in nonvalvular atrial fibrillation (AF): novel oral anticoagulants (NOACs) (apixaban, dabigatran, edoxaban, and rivaroxaban); vitamin K antagonists (VKA); aspirin; and the Watchman device. METHODS AND RESULTS: A network meta-analysis of randomized, clinical trials (RCTs) was performed. RCTs that included patients with prosthetic cardiac valves or mitral stenosis, mean or median follow-up <6 months, <200 participants, without published report in English language, and NOAC phase II studies were excluded. The placebo/control arm received either placebo or no treatment. The primary efficacy outcome was the combination of stroke (of any type) and systemic embolism. All-cause mortality served as a secondary efficacy outcome. The primary safety outcome was the combination of major extracranial bleeding and intracranial hemorrhage. A total of 21 RCTs (96 017 nonvalvular AF patients; median age, 72 years; 65% males; median follow-up, 1.7 years) were included. In comparison to placebo/control, use of aspirin (odds ratio [OR], 0.75 [95% CI, 0.60-0.95]), VKA (0.38 [0.29-0.49]), apixaban (0.31 [0.22-0.45]), dabigatran (0.29 [0.20-0.43]), edoxaban (0.38 [0.26-0.54]), rivaroxaban (0.27 [0.18-0.42]), and the Watchman device (0.36 [0.16-0.80]) significantly reduced the risk of any stroke or systemic embolism in nonvalvular AF patients, as well as all-cause mortality (aspirin: OR, 0.82 [0.68-0.99]; VKA: 0.69 [0.57-0.85]; apixaban: 0.62 [0.50-0.78]; dabigatran: 0.62 [0.50-0.78]; edoxaban: 0.62 [0.50-0.77]; rivaroxaban: 0.58 [0.44-0.77]; and the Watchman device: 0.47 [0.25-0.88]). Apixaban (0.89 [0.80-0.99]), dabigatran (0.90 [0.82-0.99]), and edoxaban (0.89 [0.82-0.96]) reduced risk of all-cause death as compared to VKA. CONCLUSIONS: The entire spectrum of therapy to prevent thromboembolism in nonvalvular AF significantly reduced stroke/systemic embolism events and mortality.

VV' Alternans Triplets on Near-Field ICD Intracardiac Electrogram is Associated with Mortality.

BACKGROUND: In heart failure patients with implantable cardioverter defibrillator (ICD) the risk of death from causes other than tachyarrhythmia is substantial. Benefit from ICD is determined by two competing risks: appropriate ICD shock or nonarrhythmic death. The goal of the study was to test predictors of competing outcomes. METHODS: Patients with structural heart disease (N = 234, mean age 58.5 ± 15.1; 71% men, 80% whites, 61% ischemic cardiomyopathy) and primary (75%) or secondary prevention ICD underwent a 5-minute baseline near-field electrogram (NF EGM) recording. VV' alternans triplets were quantified as a percentage of three sinus VV' cycles sequences of "short-long-short" or "long-short-long" order. Appropriate ICD shock for fast ventricular tachycardia (FVT, cycle length ≤240 ms)/ventricular fibrillation (VF) and composite nonarrhythmic death (pump failure death or heart transplant) served as competing outcomes. RESULTS: Over a median follow-up of 2.4 years, 26 patients (4.6% per person-year of follow-up) developed FVT/VF with ICD shock, and 35 (6.3% per person-year of follow-up) had nonarrhythmic death. In competing risk analysis, after adjustment for demographics, left ventricular ejection fraction, New York Heart Association class, cardiomyopathy type, use of class I antiarrhythmics, and diabetes, increased percentage of VV' alternans triplets (>69%) was associated with nonarrhythmic death (subhazard ratio [SHR] 2.09; 95% confidence interval [CI] 1.03-4.23; P = 0.041), rather than with FVT/VF (SHR 1.05; 95% CI 0.45-2.46; P = 0.901). Risk of nonarrhythmic death was especially high in diabetics with VV' alternans triplets in the highest quartile (SHR 3.46; 95% CI 1.41-8.50; P = 0.007). CONCLUSION: In ICD patients with structural heart disease sinus VV' alternans triplets on NF EGM is independently associated with nonarrhythmic death, rather than with FVT/VF.

The effect of antiarrhythmic medication management on atrial fibrillation ablation outcomes.

BACKGROUND: Patients commonly present for atrial fibrillation (AF) ablation while taking antiarrhythmic (AA) medications. It is unknown if AA use at the time of ablation affects procedural outcome. This study compares the AF ablation outcomes of patients who underwent ablation while on AA medications to those who were not on AA medications. METHODS AND RESULTS: A total of 180 consecutive patients who underwent their first catheter ablation of AF were identified from the Johns Hopkins Hospital AF registry and divided into 2 cohorts: those On AA at the time of ablation (127 patients, mean follow-up 24.6 months) and those Off AA at the time of ablation (53 patients, mean follow-up 20.3 months). Follow-up was performed to identify recurrent AF. There was no statistically significant difference in the percentage of patients without a recurrence of symptomatic AF (single procedure success rate) in the On and Off AA groups at 6 months postablation (53.5% vs 50.1%, P = 0.75), or by the end of follow-up (37.8% vs 41.5%, P = 0.64). For those patients who had symptomatic AF recurrence, the average time to recurrence was 6.2 ± 9.0 months in the On AA group and 4.2 ± 7.2 months in the Off AA group (P = 0.27). CONCLUSIONS: There was no statistically significant difference in the rate of symptomatic AF recurrence between the On AA and Off AA groups in this study. The use of AA medications at the time of ablation does not appear to affect procedural outcomes in this population.

Myocardial structural associations with local electrograms: a study of postinfarct ventricular tachycardia pathophysiology and magnetic resonance-based noninvasive mapping.

BACKGROUND: The association of scar on late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) with local electrograms on electroanatomic mapping has been investigated. We aimed to quantify these associations to gain insights regarding LGE-CMR image characteristics of tissues and critical sites that support postinfarct ventricular tachycardia (VT). METHODS AND RESULTS: LGE-CMR was performed in 23 patients with ischemic cardiomyopathy before VT ablation. Left ventricular wall thickness and postinfarct scar thickness were measured in each of 20 sectors per LGE-CMR short-axis plane. Electroanatomic mapping points were retrospectively registered to the corresponding LGE-CMR images. Multivariable regression analysis, clustered by patient, revealed significant associations among left ventricular wall thickness, postinfarct scar thickness, and intramural scar location on LGE-CMR, and local endocardial electrogram bipolar/unipolar voltage, duration, and deflections on electroanatomic mapping. Anteroposterior and septal/lateral scar localization was also associated with bipolar and unipolar voltage. Antiarrhythmic drug use was associated with electrogram duration. Critical sites of postinfarct VT were associated with >25% scar transmurality, and slow conduction sites with >40 ms stimulus-QRS time were associated with >75% scar transmurality. CONCLUSIONS: Critical sites for maintenance of postinfarct VT are confined to areas with >25% scar transmurality. Our data provide insights into the structural substrates for delayed conduction and VT and may reduce procedural time devoted to substrate mapping, overcome limitations of invasive mapping because of sampling density, and enhance magnetic resonance-based ablation by feature extraction from complex images.

Automated detection and characterization of complex fractionated atrial electrograms in human left atrium during atrial fibrillation.

BACKGROUND: Complex fractionated atrial electrograms (CFAEs) have been reported as ablative targets for the treatment of atrial fibrillation (AF). However, the process of CFAE identification is highly dependent on the operator's judgment. OBJECTIVE: It is the aim of the study to report our initial experience with a novel software algorithm designed to automatically detect CFAEs. METHODS: Nineteen patients (6 female, 58 +/- 8 years) who underwent catheter ablation of paroxysmal (n = 11) or persistent (n = 8) AF were included in the study. During ongoing AF, 100 +/- 15 left atrial (LA) endocardial locations were sampled under the guidance of integrated electroanatomical mapping with computed tomographic images. Bipolar electrograms recorded throughout the LA were analyzed using custom software that allows for automated detection of CFAEs. Interval confidence level (ICL), defined as the number of intervals between consecutive CFAE complexes during 2.5-second recordings, was used to characterize CFAEs. The CFAE sites with an ICL >/=5 were considered as sites with highly repetitive CFAEs, which are thought to be potential ablation targets. For purposes of analysis, the LA was divided into 6 areas: pulmonary vein (PV) ostia, posterior wall, interatrial septum, roof, mitral annulus area, and appendage. RESULTS: Among a total of 1,904 LA locations sampled in 19 patients, 1,644 (86%) were categorized as CFAE sites, whereas 260 (14%) were categorized as as non-CFAE sites. Thirty-four percent of all CFAE sites were identified as sites with highly repetitive CFAEs. Of these, 24% were located at the interatrial septum, 22% on the posterior wall, 20% at the PV ostia, 18% at the mitral annulus area, 14% on the roof, and 2.7% at the LA appendage. In all patients, highly repetitive CFAE sites were distributed in 4 or more areas of the LA. Persistent AF patients had more highly repetitive CFAE sites on the posterior wall than paroxysmal AF patients (30% +/- 7.3% vs 14% +/- 8.2%, P < .001). There was a strong trend toward more highly repetitive CFAE sites located at the PV ostia in patients with paroxysmal AF compared with persistent AF patients (24% +/- 13% vs 13% +/- 7.7%, P = .05). CONCLUSION: With the use of custom software, CFAE complexes were identified in more than 80% of the LA endocardial locations. LA sites with highly repetitive CFAE sites were located predominately in the septum, posterior wall, and PV ostia. Patients with persistent AF had a different anatomical distribution pattern of highly repetitive CFAE sites from those with paroxysmal AF, with a greater prevalence of highly repetitive CFAEs located on the posterior wall. Further studies are warranted to determine the clinical significance of these findings.

Treatment of hyperlipidemia in cardiac transplant recipients.

Of the 60,000 patients receiving heart transplants between 1982 and 2001, approximately 12,000 are currently alive. The high incidence of hyperlipidemia and coronary disease (also known as accelerated graft atherosclerosis, or AGA) in these patients warrants early prophylaxis soon after transplantation with 3-hydroxy-3-methylglutaryl (HMG) Co-A reductase inhibitors (statins). Immunosuppressive agents such as prednisone, cyclosporine, mycophenylate mofetil, and sirolimus are associated with hyperlipidemia. Statins, in addition to lowering cholesterol levels, also benefit cardiac transplant recipients via effects on the immune system and endothelial function. Recent data have demonstrated that statins decrease AGA and mortality rates. Furthermore, greater benefits are seen when statins are started early. The 2 statins shown to decrease mortality in patients after cardiac transplantation are pravastatin and simvastatin, which differ in their metabolism (pravastatin is the only statin with non-cytochrome metabolism) and lipophilicity (pravastatin is less lipophilic). Although the benefit of simvastatin has been shown to extend to 8 years after transplantation, increased adverse effects in other studies with higher doses of simvastatin have resulted in new prescribing recommendations, which state that the dose of simvastatin should probably not exceed 10 mg with cyclosporine or gemfibrozil and 20 mg with amiodarone or verapamil. The evidence for potential benefits, interactions, and adverse effects of other potential lipid-lowering drugs for this patient population, such as fibrates, niacin, fish oil, cholestyramine, and ezetimibe, are also discussed. A summary algorithm is proposed, including approaches to patients with statin-associated musculoskeletal symptoms and patients with inadequate results after initial statin therapy.

Enhanced external counterpulsation therapy: significant clinical improvement without electrophysiologic remodeling.

BACKGROUND: Enhanced external counterpulsation therapy (EECP), in addition to improving coronary flow and increasing the time to ischemia, noninvasively alters hemodynamics in patients with severe coronary artery disease (CAD). Other treatments that alter hemodynamics, for example, balloon valvuloplasty, left ventricular assist devices, and pharmacologic antagonism of the rennin-angiotensin system, promote electrophysiologic remodeling, as evidenced by alterations in the QT interval. METHODS: We studied 28 patients who completed a 7-week, 35-hour session of EECP to assess whether such therapy would also result in electrophysiologic remodeling. RESULTS: All patients had class II-III angina, imaging-proven ischemia, and severe, near-inoperable CAD. Of 28 patients, with a mean age 62 +/- 13 years (mean +/- SD), 78% were male, 46% diabetic, 82% hypertensive, 60% had undergone angioplasty, and 67% had undergone bypass surgery. The mean ejection fraction was 44% (range 25-60%). Following EECP, most patients (82%) had at least a one full class improvement in their anginal pattern. In most patients, there was substantial baseline conduction system disease present: a mean QRS of 105 +/- 19 ms. It is to be noted that there was no significant change in heart rate (HR), PR, QRS, or QT(c) intervals before and after EECP in either clinical responders or nonresponders. When analyzed by response to EECP, ejection fraction, or history of revascularization, there were still no detectable changes in ECG parameters (all P = NS). CONCLUSIONS: While EECP remains an effective treatment for severe CAD, it does not prompt early electrical remodeling of the heart.