Hodge, David O.

Dynamic QT Interval Monitoring Post‐LCSDBackgroundVideoscopic left cardiac sympathetic denervation (LCSD) is an adjunct therapy for reduction of arrhythmia‐induced events in patients with long‐QT syndrome (LQTS). LCSD reduces LQTS‐triggered breakthrough cardiac events. The temporal effects of QTc changes post‐LCSD have not been studied.MethodsWe utilized continuous QTc monitoring on 72 patients with LQTS. We evaluated acute and long‐term QTc changes in comparison to 12‐lead ECG‐derived QTc values prior to surgery, 24 hours postsurgery, and at follow up ≥3 months.ResultsSeventy‐two patients underwent LCSD at our institution (46% male, mean age at LCSD was 14 ± 10 years). The mean baseline, pre‐LCSD QTc was 505 ± 56 ms, which had decreased significantly at ≥3 months post‐LCSD to 491 ± 40 ms (P = 0.001). QTc monitoring revealed that the majority of the cohort (53/72; 74%) had a transient increase >30 ms in QTc from baseline, with an average maximum increase of 72 ± 30 ms. Resolution within 10 ms of baseline or less occurred in 57% (30/53) at 24 hours post‐LCSD.ConclusionsAlthough LQTS patients may have a paradoxically increased QTc post‐LCSD, the effects are transient in most patients. Importantly, no patients experienced any arrhythmias in the postoperative setting related to this transient rise in QTc.

Background— Most patients with repaired tetralogy of Fallot require pulmonary valve replacement (PVR), but the evaluation for and management of ventricular arrhythmia remain unclear. This study is aimed at clarifying the optimal approach to this potentially life-threatening issue at the time of PVR. Methods and Results— A retrospective analysis was performed on 205 patients with repaired tetralogy of Fallot undergoing PVR at our institution between 1988 and 2010. Median age was 32.9 (range, 25.6) years. Previous ventricular tachycardia occurred in 16 patients (8%) and 37 (16%) had left ventricular dysfunction, defined as left ventricular ejection fraction <50%. Surgical right ventricular outflow tract cryoablation was performed in 22 patients (10.7%). The primary outcome was a combined event including ventricular tachycardia, out-of-hospital cardiac arrest, appropriate implantable cardioverter defibrillator therapy, and sudden cardiac death. Freedom from the combined event at 5, 10, and 15 years was 95%, 90%, and 79%, respectively. In the first year after PVR, 2 events occurred. Conversely, in the 22 patients who underwent surgical cryoablation, a single event occurred 7 years after PVR. A history of ventricular tachycardia and left ventricular dysfunction was associated with higher risk for the combined event (hazard ratio, 4.7; P =0.004 and hazard ratio, 0.8; P =0.02, respectively). Conclusions— Patients with repaired tetralogy of Fallot undergoing PVR with history of ventricular tachycardia or left ventricular dysfunction appear to be associated with a higher risk of arrhythmic events after operation. Events in the first year after PVR are rare, and in select high-risk patients, surgical cryoablation does not seem to increase arrhythmic events and may be protective.

Epicardial Access and ObesityIntroductionPercutaneous epicardial access for ablative therapies is an increasingly common technique utilized for refractory ventricular arrhythmias. There are, however few known data on obesity and complication rates associated with this procedure.Methods and ResultsWe retrospectively reviewed the charts of subjects undergoing epicardial access at Mayo Clinic between January 2004 and June 2013. Baseline clinical and echocardiographic data were collected for each subject, who was then classified into body mass index (BMI) categories as underweight, normal weight, overweight, and obese based on a BMI of <18.5, 18.5–24.99, 25–29.99, and ≥30, respectively. Events and complications were recorded, and procedural and clinical success rates were determined.There was no statistically significant difference in access approach, procedural or clinical outcomes, or complications among the BMI categories. Note that 95.1%, 91.7%, and 93.1% derived procedural success among the normal weight, overweight, and obese categories, respectively (P value = 0.81). Similarly, there was no difference in clinical outcomes with success rates of 68.3%, 66.7%, and 75.9% between the respective groups (P value = 0.54). At 5 years, there was a trend toward increased mortality among obese individuals (28.8%) compared to normal weight (8.8%) and overweight (9.8%) patients (P value = 0.139).ConclusionPercutaneous epicardial access, mapping, and ablation can be performed in obese individuals with similar outcomes to those of lower weight category. Obesity should not preclude the use of percutaneous epicardial access when clinically indicated.

Background— Little is known about the clinical value of stress imaging studies in asymptomatic patients after percutaneous coronary intervention (PCI). Methods and Results— Residents of Olmsted County, MN, who underwent PCI were followed up for the occurrence of stress imaging (stress nuclear or stress echocardiography), coronary angiography, or coronary artery bypass grafting (without angiography) as initial procedures after PCI. Patients whose first follow-up procedure was a stress imaging test were evaluated for their symptom status at the time of the study and whether they underwent angiography or revascularization (PCI or coronary artery bypass grafting) within 90 days. Of 1848 patients who underwent PCI during the study period, 710 (38%) had stress imaging as their initial procedure after PCI, and 241 (13% of the entire cohort) were asymptomatic at the time of testing. The majority (86%) of these 241 patients underwent PCI for acute myocardial infarction or unstable angina. Within 90 days of stress imaging, 16 of the 241 asymptomatic patients underwent angiography, and 2 patients were revascularized. Stratified by timing after PCI, none of 138 asymptomatic patients tested within 2 years of PCI underwent revascularization. Two of 103 asymptomatic patients tested after 2 years from PCI underwent revascularization. Compared with patients who were asymptomatic at the time of stress imaging, patients who did not undergo any follow-up procedures (stress imaging, angiography, or coronary artery bypass grafting) after the index PCI were older, were more likely to have comorbidities, and had significantly greater all-cause mortality ( P <0.001). Conclusions— In a population-based sample of patients undergoing PCI primarily for acute coronary syndromes, 1 in 8 had subsequent stress imaging when they were asymptomatic. These stress imaging tests resulted in further revascularization in <1% of patients. The low rate of downstream revascularization suggests that stress imaging in asymptomatic patients after PCI has low value.

Introduction Pulmonary vein isolation is an effective therapy for curing symptomatic atrial fibrillation (AF). While it is known the severity of left atrial (LA) enlargement affect the success of AF ablation, little is known the impact of intracardiac pressure on the ablation outcome. Methods This prospective study consisted of 63 patients (mean age 57±9 years, 73% male) who underwent catheter-based pulmonary vein isolation for drug refractor symptomatic AF (48% paroxysmal, 52% persistent). All patients underwent simultaneous echocardiography and haemodynamic measurements including left ventricular end systolic pressure (LVEDP), mean left atrial pressure (LAP) and dP/dtmax using Millar catheter at the time of procedure during AF. Left atrial volume (LAV) was measure by biplane area length method. Recurrence of AF was defined as episodes of AF more than 5 min documented in 24h ambulatory ECG or event monitor. Results After a mean follow-up duration of 16±7 months, AF elimination off anti-arrhythmic drugs was achieved in 70 % (44/63) of patients. Among the echographic and haemodynamic measurements, the baseline LAV and mean LAP were 57.62±25.39 ml and 12.19±4.57 mm Hg in AF free patients compared to 81.20±40.88 ml (p=0.02) and 16.46±4.14 mm Hg (p=0.01) in AF recurrence groups. Univariate and multivariate analysis showed LAP was the only independent predictor of the recurrence with an adjusted odd ratio of 1.27 (95% CI 1.04 to 1.54, p=0.03, table). Conclusion LAP is a determinant of AF recurrence after AF ablation. Therapies towards reduction of LA filling pressure, especially in patients with elevated LAP, may improve the outcome of ablation. Table Baseline clinical characters in the recurrence group and non-recurrence group Non-recurrence (N=44) recurrence (N=19) Univariate Multivariate P 95% CI P 95% CI Age (ys) 57.39±9.92 59.26±10.47 0.49 0.97, 1.08 – – AF type, persistent AF no. (%) 23 (53%) 10 (50%) 0.97 0.34, 2.98 – – AF duration (ys) 5.84±5.43 8.08±7.66 0.20 0.99, 1.05 – – LA volume (mL) 57.62±25.39 81.20±40.88 0.02 1.01, 1.05 0.30 0.99, 1.05 LVEDP (mm Hg) 10.25±14.54 11.25±5.75 0.81 0.96, 1.06 – – dP/dt max (mm Hg/s) 1294.02±337.13 1211.77±225.36 0.47 0.99, 1.02 – – Mean LAPmean (mm Hg) 12.19±4.57 16.46±4.14 0.01 1.06, 1.50 0.02 1.04, 1.54 Pulmonary vein isolation is an effective therapy for curing symptomatic atrial fibrillation (AF) but the success rate ranged wide. This study aimed to investigate the effect of LAP on AF recurrence.

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.

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.