Kapa, Suraj

Background: Use of magnetic resonance imaging (MRI) brain is restricted in patients with cardiovascular implantable electronic devices (CIEDs). We proposed to determine whether mortality difference exists for patients with non–MRI-conditional CIEDs undergoing brain MRI compared with controls. Methods and Results: Retrospective analysis of prospectively collected data was performed to compare all-cause mortality in patients with CIEDs undergoing brain MRI (CIED-MRI) with 3 control groups matched for age, sex, imaging year, and type of CIED: (1) no CIED, brain MRI (no–CIED-MRI); (2) CIED, brain computerized tomography (CT) scan (CIED-CT); and (3) no CIED, brain CT (no–CIED-CT). The primary outcome was a significant difference ( P <0.05) between estimated mortality rates. Secondary outcomes were changes in device function before and after brain MRI. The estimated all-cause mortality at 5 years for the CIED-MRI group [mean age (±SD), 68.2 years (15.3 years); 61.2% men] was not significantly different from patients who underwent CT with or without a device (CIED-CT group: hazard ratio, 0.814; 95% confidence interval, 0.593–1.117; P =0.2; no–CIED-CT group: hazard ratio, 1.149; 95% confidence interval, 0.818–1.613; P =0.4). There was a significant increase in mortality between CIED-MRI and no–CIED-MRI groups (hazard ratio, 1.463; 95% confidence interval, 1.019–2.099; P =0.04). Conclusions: Brain MRI in patients with CIEDs does not carry an increased mortality risk compared with brain CT and can be performed with adherence to appropriate procedural protocols.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting approximately 3 million Americans, and is a prognostic marker for stroke, heart failure and even death [1]. 12-lead electrocardiogram (ECG) is used to monitor normal sinus rhythm (NSR) and also detect AF. Although the persistent form of AF can be detected relatively easy, detecting paroxysmal AF is often a challenge since requiring continuous monitoring, which becomes expensive and cumbersome to collect lot of ECG data [1]. Several researchers have attempted to develop new methods to discriminate NSR and AF which are based on R-R interval analysis, linear methods, filtering, spectral analysis, statistical approaches such as entropy etc. which faces limitation of successfully detecting AF of all types with high sensitivity and specificity using short time ECG data [1–3]. The major issues with these approaches is that they often distort the ECG by several pre-processing steps with filters, do not provide reliable discrimination using short ECG time series data and many of them lack real-time capability that makes it difficult to trust the data for diagnosis and treatment. Both clinical and scientific communities recognize these difficulties and the necessity to develop novel methods that can enable accurate monitoring and detection of AF [2]. In addition, robust detection and classification algorithms are essential for delivering appropriate therapy for implantable cardioverter defibrillators (ICD) to provide lifesaving timely action. In this work, the authors propose and demonstrate the application of a multiscale frequency (MSF) approach [4] for accurate detection and discrimination between AF and NSR ECG traces taken from publically available Physionet database. The MSF approach takes into account the contribution from various frequencies in ECG and thus yield valuable information regarding the chaotic nature of AF. Therefore, we demonstrate that MSF can capture the complexity of AF which is associated with higher MSF value compared with NSR thus enabling robust discrimination e AF manifests itself with numerous chaotic frequencies within the body surface ECG,. We validate the feasibility of this technique to discriminate NSR from AF.

Background: Recognition of rates and causes of hard, patient-centered outcomes of death and cerebrovascular events (CVEs) after heart rhythm disorder management (HRDM) procedures is an essential step for the development of quality improvement programs in electrophysiology laboratories. Our primary aim was to assess and characterize death and CVEs (stroke or transient ischemic attack) after HRDM procedures over a 17-year period. Methods: We performed a retrospective cohort study of all patients undergoing HRDM procedures between January 2000 and November 2016 at the Mayo Clinic. Patients from all 3 tertiary academic centers (Rochester, Phoenix, and Jacksonville) were included in the study. All in-hospital deaths and CVEs after HRDM procedures were identified and were further characterized as directly or indirectly related to the HRDM procedure. Subgroup analysis of death and CVE rates was performed for ablation, device implantation, electrophysiology study, lead extraction, and defibrillation threshold testing procedures. Results: A total of 48 913 patients (age, 65.7±6.6 years; 64% male) who underwent a total of 62 065 HRDM procedures were included in the study. The overall mortality and CVE rates in the cohort were 0.36% (95% confidence interval [CI], 0.31–0.42) and 0.12% (95% CI, 0.09–0.16), respectively. Patients undergoing lead extraction had the highest overall mortality rate at 1.9% (95% CI, 1.34–2.61) and CVE rate at 0.62% (95% CI, 0.32–1.07). Among patients undergoing HRDM procedures, 48% of deaths directly related to the HDRM procedure were among patients undergoing device implantation procedures. Overall, cardiac tamponade was the most frequent direct cause of death (40%), and infection was the most common indirect cause of death (29%). The overall 30-day mortality rate was 0.76%, with the highest being in lead extraction procedures (3.08%), followed by device implantation procedures (0.94%). Conclusions: Half of the deaths directly related to an HRDM procedure were among the patients undergoing device implantation procedures, with cardiac tamponade being the most common cause of death. This highlights the importance of the development of protocols for the quick identification and management of cardiac tamponade even in procedures typically believed to be lower risk such as device implantation.

Background— Ventricular tachycardia and premature ventricular complexes (PVCs) most frequently occur in the context of structural heart disease. However, the burden of idiopathic ventricular arrhythmias (IVA) in the general population is unknown. Methods and Results— We identified incident cases of IVA between 2005 and 2013 from Olmsted County, Minnesota, using the Rochester Epidemiology Project database. For PVC cohorts, we included those with frequent (defined as ≥100 PVC/24 hours) symptomatic PVCs. We defined IVA-associated cardiomyopathy as a drop in ejection fraction of ≥10% from baseline. Between 2005 and 2013, we identified 614 individuals with incident IVA (229 [37.3%] were male; average age was 52.1±17.2 years). Of these, 177 (28.8%) had idiopathic ventricular tachycardia, 408 (66.5%) had symptomatic PVCs, and 29 (4.7%) had IVA-associated cardiomyopathy. The age- and sex-adjusted incidence rates in 2005 to 2007, 2008 to 2010, and 2011 to 2013 were 44.9 per 100 000 (95% confidence interval [CI], 38.0–51.8), 47.6 per 100 000 (95% CI, 40.8–54.5), and 62.0 per 100 000 (95% CI, 54.4–69.6), respectively. In idiopathic ventricular tachycardia, there was an increase in incidence rate with ages ( P <0.001) but not between sexes ( P =0.12). The age-adjusted incidence of symptomatic PVC was higher in females than in males (46.2 per 100 000 [95% CI, 40.9–51.6] versus 20.5 per 100 000 [95% CI, 16.8–24.3]; P <0.001). The small number of individuals with IVA-associated cardiomyopathy precluded any formal testing. Conclusions— The incidence of IVA is increasing. Furthermore, overall incidence increases with age. Although the rate of idiopathic ventricular tachycardia is similar across sexes, women have a higher incidence of symptomatic PVC.

VT Ablation in LVAD RecipientsBackgroundPatients with advanced heart failure (HF) are predisposed to ventricular arrhythmias (VAs), particularly following implantation of a left ventricular assist device (LVAD). There is minimal evidence for appropriate management strategies.ObjectivesThis study aimed to compare the burden of VA and response to ablation performed either before or following LVAD implantation.MethodsWe created a retrospective cohort of patients who underwent both VA ablation and Heart Mate II (Thoratec, Pleasanton, CA, USA) LVAD implantation at Mayo Clinic (Rochester, MN, USA). Patients were stratified based on whether they underwent VA ablation before (pre‐LVAD) or after LVAD (post‐LVAD) implantation. Descriptive analyses assessed 6‐month arrhythmia burden in relation to LVAD implantation and VA ablation.ResultsA total of 9 patients underwent both LVAD implantation and VA ablation. There were 3 and 6 patients, respectively, in the pre‐LVAD and post‐LVAD cohorts. Among patients in the pre‐LVAD cohort, the median number of VAs tended to increase after ablation (9 vs. 72) and decreased after LVAD implantation (72 vs. 63). Similarly among patients in the post‐LVAD cohort, the median burden of VAs increased after LVAD implantation (1 vs. 22) and the median burden decreased after ablation (22 vs. 13). Two of 6 patients had substrate related to the LVAD inflow cannula site, while other substrate was not related directly to the cannula.ConclusionsIn patients with progressive HF and LVAD implantation, ablation is associated with reduced VA rates. In LVAD patients, most VAs arise from substrate unrelated to the inflow cannula site.

Endovascular Stimulation for Treatment of HypotensionBackgroundWe have previously shown that sympathetic ganglia stimulation via the renal vein rapidly increases blood pressure. This study further investigated the optimal target sites and effective energy levels for stimulation of the renal vasculatures and nearby sympathetic ganglia for rapid increase in blood pressure.MethodsThe pre‐study protocol for endovascular stimulations included 2 minutes of stimulation (1–150 V and 10 pulses per second) and at least 2 minutes of rest during poststimulation. If blood pressure and/or heart rate were changed during the stimulation, time to return to baseline was allowed prior to the next stimulation.ResultsIn 11 acute canine studies, we performed 85 renal artery, 30 renal vein, and 8 hepatic vasculature stimulations. The mean arterial pressure (MAP) rapidly increased during stimulation of renal artery (95 ± 18 mmHg vs. 103 ± 15 mmHg; P < 0.0001), renal vein (90 ± 16 mmHg vs. 102 ± 20 mmHg; P = 0.001), and hepatic vasculatures (74 ± 8 mmHg vs. 82 ± 11 mmHg; P = 0.04). Predictors of a significant increase in MAP were energy >10 V focused on the left renal artery, bilateral renal arteries, and bilateral renal veins (especially the mid segment). Overall, heart rate was unchanged, but muscle fasciculation was observed in 22.0% with an output >10 V (range 15–150 V). Analysis after excluding the stimulations that resulted in fasciculation yielded similar results to the main findings.ConclusionsStimulation of intra‐abdominal vasculatures promptly increased the MAP and thus may be a potential treatment option for hypotension in autonomic disorders. Predictors of optimal stimulation include energy delivery and the site of stimulation (for the renal vasculatures), which informs the design of subsequent research.