Machine learning applications on neonatal sepsis treatment: a scoping review.

INTRODUCTION: Neonatal sepsis is a major cause of health loss and mortality worldwide. Without proper treatment, neonatal sepsis can quickly develop into multisystem organ failure. However, the signs of neonatal sepsis are non-specific, and treatment is labour-intensive and expensive. Moreover, antimicrobial resistance is a significant threat globally, and it has been reported that over 70% of neonatal bloodstream infections are resistant to first-line antibiotic treatment. Machine learning is a potential tool to aid clinicians in diagnosing infections and in determining the most appropriate empiric antibiotic treatment, as has been demonstrated for adult populations. This review aimed to present the application of machine learning on neonatal sepsis treatment. METHODS: PubMed, Embase, and Scopus were searched for studies published in English focusing on neonatal sepsis, antibiotics, and machine learning. RESULTS: There were 18 studies included in this scoping review. Three studies focused on using machine learning in antibiotic treatment for bloodstream infections, one focused on predicting in-hospital mortality associated with neonatal sepsis, and the remaining studies focused on developing machine learning prediction models to diagnose possible sepsis cases. Gestational age, C-reactive protein levels, and white blood cell count were important predictors to diagnose neonatal sepsis. Age, weight, and days from hospital admission to blood sample taken were important to predict antibiotic-resistant infections. The best-performing machine learning models were random forest and neural networks. CONCLUSION: Despite the threat antimicrobial resistance poses, there was a lack of studies focusing on the use of machine learning for aiding empirical antibiotic treatment for neonatal sepsis.

Outcomes in congenital and childhood complete atrioventricular block: A meta-analysis.

BACKGROUND: The long-term outcomes of patients with congenital and childhood complete atrioventricular block (CCAVB/CAVB) after pacemaker implantation are unclear. METHODS: We performed a meta-analysis of all the studies of CCAVB. A systematic search of PubMed and CENTRAL databases from January 1, 1967 to January 31, 2020 was performed. The quality of studies included was critically appraised using the Newcastle-Ottawa scale, and outcome data were analyzed using the restricted maximum likelihood function. RESULTS: Twenty-nine studies were eligible for analysis, with a total of 1553 patients. The all-cause-mortality was 5.7% (95% confidence interval [CI]: 2.5%-9.9%), while pacing-induced cardiomyopathy (PICM) was seen in 3.8% (95% CI: 1.2-7.2). Diagnosis at birth (effect size [ES] [95%CI]: -2.23 [-0.36 to -0.10]; p < .001), presence of congenital heart disease (ES [95%CI]: -0.67 [0.41-0.93]; p < .001), younger age at pacemaker implantation (ES [95%CI]: -0.01 [-0.02 to -0.001]; p = .02), and duration of pacing (ES [95%CI]: -0.03 [-0.05 to -0.003]; p = .03), were associated with an higher mortality on binominal logistic regression. None of the parameters were significant on multivariate analysis. CONCLUSION: Pooled proportional mortality in patients with CCAVB and CAVB is 5.7% with an infrequent incidence of PICM (3.8%) in the paced patients with AVB suggesting that pacing in these patients is an effective management strategy with a low incidence of long-term side effects. Registry and randomized data can throw additional light regarding the natural history and appropriate management strategy in these patients.

A histological study of the atria in patients with isolated rheumatic mitral regurgitation with and without atrial fibrillation.

BACKGROUND: There is a high incidence of atrial fibrillation (AF) in patients with isolated rheumatic mitral regurgitation (MR). The histopathologic changes in the atria of patients with isolated rheumatic MR with and without AF are unknown. OBJECTIVES: We aimed to determine the histological findings in patients with isolated severe rheumatic MR with and without AF. METHODS: Patients with severe isolated rheumatic MR undergoing valve replacement surgeries underwent endocardial biopsies from right atrial appendage, left atrial appendage, right free wall, left free wall, left posterior wall, and mitral valve. Group I consisted of patients in sinus rhythm (SR), and Group II included patients with AF. We analyzed and compared these 10 histological features in the biopsies of patients in Groups I and II. RESULTS: Of the 25 patients, 12 were in Group I and 13 in Group II. In Group I, patients had severe myocyte hypertrophy (60% vs. 18%, p = .04) that was significantly more in the right atrium (22.7% vs. 11.4%, p = .059). Interstitial adipose tissue deposition was more common in Group I (30% vs. 25%, p = .06). Interstitial fibrosis was evenly distributed at all sites without significant difference between the two groups. Group II patients had a higher prevalence and severity of vacuolar degeneration (91% vs. 60%, p = .09). CONCLUSIONS: Patients with isolated severe rheumatic MR and AF have more vacuolar degeneration in the atrial tissue. Patients with SR have myocyte hypertrophy and interstitial adipose tissue deposition. Interstitial fibrosis is uniformly distributed in patients in SR and AF.

Impact of intracardiac echocardiography on readmission morbidity and mortality following atrial fibrillation ablation.

INTRODUCTION: The use of intracardiac echocardiography (ICE) is beneficial during the ablation of atrial fibrillation (AF). Evidence is conflicting regarding the clinical impact of using ICE on arrhythmia recurrence and mortality. METHODS: Patients undergoing catheter ablation of AF during 2010-2017 were identified using the International Classification of Diseases-9th and 10th Revision-Clinical Modification (ICD-9-CM and ICD-10-CM) from the Nationwide Readmissions Database. Propensity matching was used to generate a control group. Patient demographics, Charlson comorbidity indexes, time from discharge to readmission, and the reason of readmission were extracted. RESULTS: From 2010 to 2017, 51 129 patients were included in the analysis out of which ICE was used in 8005 (15.7%) patients. The in-hospital mortality at readmission was significantly higher in the patients without ICE use (2.9% vs. 1.7%, p = .02). The length of stay (LOS) at readmission was significantly higher in non-ICE arm (median [interquartile range, IQR]: 3 [2-6] vs. 2 [3-5] days, p < .0001) with similar healthcare-associated cost (HAC) in both the groups (median [IQR]: US$7507.3 [4057.8-15 474.2] vs. 7339.4 [4024.8-15 191.6], p = .43). Freedom from readmission was 12% higher (hazard ratio [HR] [95% confidence interval, CI]: 0.88 [0.83-0.94], p < .0001) with the use of ICE at 90-day follow-up, which was driven by 24% reduction in heart failure (HF) at follow-up (HR [95% CI]: 0.76 [0.60-0.96], p = .02). CONCLUSIONS: ICE use during AF ablation procedure reduces readmissions at 90 days by 12%, driven by a 24% decrease in HF-related admissions. The non-ICE arm showed a significantly higher LOS which offsets marginally higher HAC in the ICE arm.

Evaluation of a novel cardiac signal processing system for electrophysiology procedures: The PURE EP 2.0 study.

BACKGROUND: Intracardiac electrogram data remain one of the primary diagnostic inputs guiding complex ablation procedures. However, the technology to collect, process, and display intracardiac signals has known shortcomings and has not advanced in several decades. OBJECTIVE: The purpose of this study was to evaluate a new signal processing platform, the PURE EP™ system (PURE), in a multi-center, prospective study. METHODS: Intracardiac signal data of clinical interest were collected from 51 patients undergoing ablation procedures with PURE, the signal recording system, and the 3D mapping system at the same time stamps. The samples were randomized and subjected to blinded, controlled evaluation by three independent electrophysiologists to determine the overall quality and clinical utility of PURE signals when compared to conventional sources. Each reviewer assessed the same (92) signal sample sets and responded to (235) questions using a 10-point rating scale. If two or more reviewers rated the PURE signal higher than the control, it was deemed superior. RESULTS: A total of 93% of question responses showed consensus amongst the blinded reviewers. Based on the ratings for each pair of signals, a cumulative total of 164 PURE signals out of 218 (75.2%) were statistically rated as Superior for this data set (p < .001). Only 14 PURE signals out of 218 were rated as Inferior (6.4%). CONCLUSION: The PURE intracardiac signals were statistically rated as superior when compared to conventional systems.

Catheter ablation of premature ventricular contractions originating from periprosthetic aortic valve regions.

BACKGROUND: Little is known about the ablation outcomes of premature ventricular contractions (PVCs) that originate from the periprosthetic aortic valve (PPAV) regions of patients with aortic valve replacement (AVR). METHODS AND RESULTS: Our study had 11 patients who underwent catheter ablation for PVCs arising from the PPAV regions (bioprosthetic aortic valve, n = 5; mechanical aortic valve, n = 6). The PVC characteristics, procedure characteristics, and efficacy of ablation were compared with the control group (n = 33). At baseline, the PPAV group had a lower left ventricular ejection fraction (mean [SD], 41% [12%] vs. 51% [8%]; p = .002). The rate of acute ablation success was 90.9% in the PPAV group. Ablation sites were identified above the left coronary cusp (LCC) and right coronary cusp commissure (LRCC) in one PVC, below the prosthetic valve in eight PVCs (four below LCC and four below LRCC), and within the distal coronary sinus in two PVCs. The mean procedure time, fluoroscopy time, and radiation in the PPAV group were all significantly greater than those in the control group (all p < .05). However, the number of radiofrequency ablation energy deliveries was not different. The PPAV group had a long-term success rate compared with the control group (72.7% vs. 87.9%, p = .48) and an increase of left ventricular ejection fraction from 43% to 49% after successful PVC ablation at follow-up (p < .001). Echocardiography showed no significant change in valve regurgitation after ablation. No new atrioventricular block occurred. CONCLUSION: PVCs arising from PPAV regions can be successfully ablated in patients with prior AVR, without damaging the prosthetic aortic valve and atrioventricular conduction.

A randomized study of yoga therapy for the prevention of recurrent reflex vasovagal syncope.

AIMS: Vasovagal syncope (VVS) is a common cardiovascular dysautonomic disorder that significantly impacts health and quality of life (QoL). Yoga has been shown to have a positive influence on cardiovascular autonomics. This study assessed the effectiveness of yoga therapy on the recurrence of VVS and QoL. METHODS AND RESULTS: We randomized subjects with recurrent reflex VVS (>3 episodes in the past 1 year) and positive head-up tilt test to guideline-directed therapy (Group 1) or yoga therapy (Group 2). Patients in Group 1 were advised guideline-directed treatment and Group 2 was taught yoga by a certified instructor. The primary endpoint was VVS recurrences and QoL. Between June 2015 and February 2017, 97 highly symptomatic VVS patients were randomized (Group 1: 47 and Group 2: 50). The mean age was 33.1 ± 16.6 years, male:female of 40:57, symptom duration of 17.1 ± 20.7 months, with a mean of 6.4 ± 6.1 syncope episodes. Over a follow-up of 14.3 ± 2.1 months Group 2 had significantly lower syncope burden compared with Group 1 at 3 (0.8 ± 0.9 vs. 1.8 ± 1.4, P < 0.001), 6 (1.0 ± 1.2 vs. 3.4 ± 3.0, P < 0.001), and at 12 months (1.1 ± 0.8 vs. 3.8 ± 3.2, P < 0.001). The Syncope functional score questionnaire was significantly lower in Group 2 compared with Group 1 at 3 (31.4 ± 7.2 vs. 64.1 ± 11.5, P < 0.001), 6 (26.4 ± 6.3 vs. 61.4 ± 10.7, P < 0.001), and 12 months (22.2 ± 4.7 vs. 68.3 ± 11.4, P < 0.001). CONCLUSION: For patients with recurrent VVS, guided yoga therapy is superior to conventional therapy in reducing symptom burden and improving QoL.

Incremental benefit of a novel signal recording system during mapping and ablation.

AIMS: Current electrophysiology signal recording and mapping systems have limited dynamic range (DR) and bandwidth, which causes loss of valuable information during acquisition of cardiac signals. We evaluated a novel advanced signal processing platform with the objective to obtain and assess additional information of clinical importance. METHODS AND RESULTS: Over 10 canines, we compared intracardiac recordings within all cardiac chambers, in various rhythms, in pacing and during radiofrequency (RF) ablation across two platforms; a conventional system and the PURE EP™ [(PEP); Bio Sig Technologies, Inc., Los Angeles, CA, USA]. Recording cardiac signals with varying amplitudes were consistently and reproducibly observed, without loss of detail or introduction of artefact. Further the amplitude of current of injury (COI) on the unipolar signals correlated with the instantaneous contact force (CF) recorded on the sensing catheter in all the animals (r2 = 0.94 in ventricle). The maximum change in the unipolar COI correlated with the change in local electrogram amplitude during non-irrigated RF ablation (r2 = 0.61 in atrium). Reduction in artefact attributable to pacing (20 sites) and noise during ablation (48 sites) was present on the PEP system. Within the PEP system, simultaneous display of identical signals, filtered differently, aided the visualization of discrete conduction tissue signals. CONCLUSION: Compared to current system, the PEP system provided incremental information including identifying conduction tissue signals, estimates of CF and a surrogate for lesion formation. This novel signal processing platform with increased DR and minimal front-end filtering may be useful in clinical practice.

Safety and Efficacy of Ibutilide for Acute Pharmacological Cardioversion of Rheumatic Atrial Fibrillation.

INTRODUCTION: Ibutilide is indicated for acute cardioversion of nonvalvular atrial fibrillation (AF). However, its efficacy and safety in the pharmacological cardioversion of rheumatic AF are unknown. METHODS: Patients with mild-to-moderate rheumatic mitral valve (MV) disease with symptomatic, paroxysmal, or persistent AF were included in the analysis. Intravenous ibutilide was administered at doses tailored to body weight (0.5-2.0 mg) for over 10 min. The primary end point was efficacy, assessed as the rate of conversion of AF to sinus rhythm. The secondary end point was safety, including arrhythmic events and death within 24 h of drug initiation. RESULTS: From June 2016 to October 2018, 165 patients (94 with mitral stenosis, 23 with mitral regurgitation, 11 with mixed MV disease, and 37 with MV replacement) received ibutilide (mean dose 0.90 ± 0.54 mg). Ibutilide successfully converted AF to sinus rhythm in 127/165 (76.9%) patients, with a conversion time of 7.9 ± 4.1 min. The QTc increased from 419.9 ± 15.8 to 487.5 ± 34 ms after ibutilide administration (p < 0.001). The mean change in QTc after ibutilide administration (∆QTc) was 72.01 ± 36.03. There were no deaths, but 3 patients (1.8%) developed torsades de pointes (TdP) requiring defibrillation 55 ± 37 min after infusion. CONCLUSION: Ibutilide cardioverted 77% of rheumatic AF to sinus rhythm, indicating its potential as a clinically useful option for pharmacological cardioversion of rheumatic AF. TdP is a potentially serious adverse event that requires careful monitoring.

MRI in patients with cardiac implantable electronic devices: A comprehensive review.

Magnetic resonance imaging (MRI) has become a commonly used non-ionizing radiation dependent imaging modality which has an excellent spatial resolution with the capability to provide physiological information. Cardiac implantable electronic devices (CIEDs) are used in modern cardiology with a frequency of 1:50 over 75 years of age and nearly one in three people in this population required MRI during their lifetime. Changes in the CIED structure, electronics, and algorithms paired with changes in the protocol design of MRI have created a relatively safe environment for performing MRI in patients with CIED. Despite their documentation in literature and a guideline document from a professional society, significant skepticism exists in doing MRI in patients with CIEDs. We intend to give an overview of interactions between MRI and CIEDs, including the evidence available in this regard and conclude with the suggestion of a protocol for safely carrying out an MRI in patients with CIEDs.

Effects of permanent cardiac pacing on ventricular repolarization when compared to cardioneuroablation.

INTRODUCTION: The impact of cardioneuroablation (CNA) on ventricular repolarization by using corrected QT interval (QTc) measurements has been recently demonstrated. The effects of cardiac pacing (CP) on ventricular repolarization have not been studied in patients with vasovagal syncope (VVS). We sought to compare ventricular repolarization effects of CNA (group 1) with CP (group 2) in patients with VVS. METHODS: We enrolled 69 patients with age 38 ± 13 years (53.6% male), n = 47 in group 1 and n = 22 in group 2. Clinical diagnosis of cardioinhibitory type was supported by cardiac monitoring or tilt testing. QTc was calculated at baseline (time-1), at 24 h after ablation (time-2), and at 9-12 months (time-3) in the follow-up. RESULTS: In the group 1, from time-1 to time-2, a significant shortening in QTcFredericia (from 403 ± 27 to 382 ± 27 ms, p < 0.0001), QTcFramingham (from 402 ± 27 to 384 ± 27 ms, p < 0.0001), and QTcHodges (from 405 ± 26 to 388 ± 24 ms, p < 0.0001) was observed which remained lower than baseline in time-3 (373 ± 29, 376 ± 27, and 378 ± 27 ms, respectively). Although the difference between measurements in time-1 and time-2 was not statistically significant for QTcBazett, a significant shortening was detected between time-1 and time-3 (from 408 ± 30 to 394 ± 33, p = 0.005). In the group 2, there was no time-based changes on QTc measurements. In the linear mixed model analysis, the longitudinal reduction tendency in the QTcFredericia and QTcFramingham was more pronounced in group 1. CONCLUSIONS: Our results demonstrate that CNA reduces QTc levels through neuromodulation effect whereas CP has no effect on ventricular repolarization in patients with VVS.

Amyloidosis in surgically resected atrial appendages: a study of 345 consecutive cases with clinical implications.

Histomorphologic parameters of atrial appendages removed during the Cox-Maze procedure have been shown to correlate with recurrence of atrial fibrillation. While amyloid deposition has been noted within atrial appendages, the incidence and significance remains incompletely understood. More accurate amyloid typing methodologies and targeted pharmacotherapeutics have recently been developed, prompting pathologists to provide more detailed information about the type of amyloid identified in such samples. This study sought to fully characterize the morphologic characteristics of atrial amyloid as well as its incidence and clinical significance. Tissue archives were queried for atrial appendages removed during the cardiac surgeries (2010-2014). Patient demographics, imaging features, and salient clinical findings were recorded. Pattern and extent of amyloid deposition were recorded. Typing of the amyloid protein, when present, was performed on a subset of cases by laser capture microdissection with mass spectrometry-based proteomic analysis. A total of 383 atrial appendages from 345 consecutive patients were included in the study (mean age, 69 years; range, 26-92 years). Amyloid was present in 46% of patients. A linear relationship was observed between age and presence of atrial amyloidosis. Women were more likely to have atrial amyloidosis. Two distinct morphologies of amyloid were observed: filamentous and nonfilamentous, and correlated perfectly with amyloid type (filamentous = AANF-type amyloid; nonfilamentous = ATTR-type amyloid). Filamentous deposits were observed in 91% of those with amyloid. Amyloid was more likely to be found in the left atrial appendage than the right. Patients with atrial amyloid, irrespective of type, were more likely to have experienced stroke or TIA and more likely to have atrial arrhythmia preoperatively. Postoperatively, those with atrial amyloid are more likely to experience recurrence of arrhythmia than those who did not have atrial amyloid. Understanding the morphologic characteristics of AANF-type amyloid will allow for identification by the light microscopy and obviates the need for expensive ancillary typing techniques. The finding of nonfilamentous amyloid, should still prompt confirmation of amyloid type so that targeted therapy may be employed.

What are the atrioventricular delays in right ventricular apical and septal pacing for optimal hemodynamics in patients with normal left ventricular function?

INTRODUCTION: There is a surge of interest in alternate site pacing to prevent pacing-induced left ventricular dysfunction. However, little is known regarding the appropriate atrioventricular (AV) delay between right ventricular (RV) septal and RV apical pacing for optimal hemodynamic benefit. OBJECTIVES: To determine the programmed values of atrial sensed and atrial paced AV delays in basal RV septal and apical RV pacing that results in the maximum delivered stroke volume (SV). METHODS: We calculated the Doppler-derived SV at various sensed and paced AV delays in 50 patients with complete AV block implanted with a dual-chamber pacemaker (group A: 25 RV apical pacing; group B: 25 RV septal pacing). The hemodynamic difference in terms of the SV between sensed and paced AV delay, corresponding to the site of RV pacing was then compared for statistical significance. RESULTS: In group A, maximal SV was derived at a sensed AV delay of 123.2 ± 11 ms and paced AV delay of 129.2 ± 10 ms, and in group B, at a sensed AV delay of 123.6 ± 8 ms and paced AV delay of and 132.8 ± 7 ms. At these intervals, there was no difference in the SV between septal and apical RV pacing (P = .28 and .22, respectively). CONCLUSION: The atrial sensed and atrial paced AV delays for septal and apical RV pacing for optimal hemodynamics are similar. For optimal hemodynamics, the atrial paced AV delay is longer than the atrial sensed AV delay.

Fibroplasty (venoplasty) to facilitate transvenous lead placement: A single-center experience.

INTRODUCTION: Venous stenosis is a well-recognized complication of transvenous leads (TVLs) that is encountered during lead revisions or device upgrades. We here report the outcomes of TVL placement facilitated by fibroplasty or tunneling (TUN) procedure. METHODS: We conducted a single-center retrospective cohort study of all patients undergoing TVL implantation requiring fibroplasty or TUN from 2005 to 2017. Medical records and procedure reports were reviewed for relevant data. Outcomes for fibroplasty and TUN to facilitate TVL placement were compared. RESULTS: Sixty patients had fibroplasty and thirty-five patients had a TUN procedure. There was no difference in procedure success rates between the two groups (97% fibroplasty vs. 100% TUN; p = .98). The fluoroscopy time was longer (fibroplasty = 39.7 ± 21.5 min vs. TUN = 29.2 ± 21.3 min; p = .01) and the total procedural time was shorter in the fibroplasty group (fibroplasty = 247 ± 77.8 min vs. TUN = 287 ± 77.1 min; p = .01). TUN was associated with a significantly higher incidence of acute complications (fibroplasty = 0 vs. TUN = 8; p = .002) most requiring invasive intervention and/or transfusion with blood products. Long-term complications requiring additional device-related procedures were comparable between the two groups (fibroplasty = 6 vs. TUN = 6; logrank p = .21). CONCLUSIONS: For patients with venous stenosis requiring additional TVL, balloon fibroplasty is associated with similar rates of success and a significantly decreased incidence of acute complications when compared with subcutaneous TUN.

Prospective evaluation of the utility of magnetic resonance imaging in patients with non-MRI-conditional pacemakers and defibrillators.

BACKGROUND: Magnetic resonance imaging (MRI) in patients with legacy cardiovascular implantable electronic devices (CIEDs) in situ is likely underutilized. We hypothesized the clinical benefit of MRI would outweigh the risks in legacy CIED patients. METHODS: This is a single-center retrospective study that evaluated and classified the utility of MRI using a prospectively maintained database. The outcomes were classified as aiding in diagnosis, treatment, or both for the patients attributable to the MRI. We then assessed the incidence of adverse effects (AE) when the MRI was performed. RESULTS: In 668, MRIs performed on 479 patients, only 13 (1.9%) MRIs did not aid in the diagnosis or treatment of the patient. Power-on reset events without clinical sequelae in three scans (0.45%) were the only AE. The probability of an adverse event happening without any benefit from the MRI scan was 1.1 × 10-4 . A maximum benefit in diagnosis using MRI was obtained in ruling out space-occupying lesions (121/185 scans, 65.4%). Scans performed in patients for elucidating answers to queries in treatment were most frequently done for disease staging at long term follow-up (167/470 scans, 35.5%). Conservative treatment (184/470 scans, 39%) followed by medication changes (153/470 scans, 28.7%) were the most common treatment decisions made. CONCLUSIONS: The utility of MRI in patients with non-MRI-conditional CIEDs far outweighs the risk of adverse events when imaging is done in the context of a multidisciplinary program that oversees patient safety.

Defining the substrate for ventricular tachycardia ablation: The impact of rhythm at the time of mapping.

BACKGROUND: Voltage mapping is critical to define substrate during ablation. In ventricular tachycardia, abnormal potentials may be targets. However, wavefront of activation could impact local signal characteristics. This may be particularly true when comparing sinus rhythm versus paced rhythms. We sought to determine how activation wavefront impacts electrogram characteristics. METHODS: Patients with ischemic cardiomyopathy, ventricular tachycardia, and without fascicular or bundle branch block were included. Point by point mapping was done and at each point, one was obtained during an atrial paced rhythm and one during a right ventricular paced rhythm. Signals were adjudicated after ablation to define late potentials, fractionated potentials, and quantify local voltage. Areas of abnormal voltage (defined as <1.5 mV) were also determined. RESULTS: 9 patients were included (age 61.3 ± 9.2 years, 56% male, mean LVEF 34.9 ± 8.6%). LV endocardium was mapped with an average 375 ± 53 points/rhythm. Late potentials were more frequent during right ventricular pacing (51 ± 21 versus 32 ± 15, p < 0.01) while overall scar area was higher during atrial pacing (22 ± 11% vs 13 ± 7%, p < 0.05). In 1/9 patients, abnormal potentials were seen during a right ventricular paced rhythm that were not apparent in an atrial paced rhythm, ablation of which resulted in non-inducibility. CONCLUSION: Rhythm in which mapping is performed has an impact on electrogram characteristics. Whether one rhythm is preferable to map in remains to be determined. However, it is possible defining local signals during normal conduction as well as variable paced rhythms may impart a greater likelihood of elucidating arrhythmogenic substrate.

Mortality and Cerebrovascular Events After Heart Rhythm Disorder Management Procedures.

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.

Sudden cardiac arrest and ventricular arrhythmias following first type I myocardial infarction in the contemporary era.

INTRODUCTION: Myocardial infarction (MI) is associated with an increase in subsequent heart failure (HF), recurrent ischemic events, sudden cardiac arrest, and ventricular arrhythmias (SCA-VA). The primary objective of the study to determine the role of intercurrent HF and ischemic events on the development of SCA-VA following first type I MI. METHODS AND RESULTS: A retrospective cohort study of patients experiencing first type 1 MI in Olmsted County, Minnesota (2002-2012) was conducted by identifying patients using the medical records linkage system (Rochester epidemiology project). Patients aged ≥18 years were followed from the time of MI till death or 31 July, 2017. Intercurrent HF and ischemic events were the primary exposures following MI and their association with outcome SCA-VA was assessed. Eight hundred and sixty-seven patients (mean age was 63 ± 14.5 years; 69% male; 49.8% ST-elevation myocardial infarction) who had their first type I MI during the study period were included. Majority of acute MI patients were revascularized using percutaneous coronary intervention and bypass surgery (628 [72.43%] and 87 [10.03%] respectively). During a mean follow-up of 7.69 ± 4.17 years, HF, recurrent ischemic events and SCA-VA occurred in 155 (17.9%), 245 (28.3%), and 40 (4.61%) patients respectively. Low ejection fraction (adjusted hazard ratio [HR] 0.95; 95% confidence interval [CI], 0.93-0.98; P < .001), intercurrent HF (adjusted HR 3.11; 95% CI, 1.39-6.95; P = .006) and recurrent ischemic events (adjusted HR 3.47; 95% CI, 1.68-7.18; P < .001) were associated with subsequent SCA-VA. CONCLUSION: SCA-VA occurred in a small proportion of patients after MI and is associated with intercurrent HF and recurrent ischemic events.

Electroporation of epicardial autonomic ganglia: Safety and efficacy in medium-term canine models.

BACKGROUND: Endocardial radiofrequency ablation of epicardial ganglionic plexus (GP) for atrial fibrillation (AF) is complicated by myocardial damage. OBJECTIVES: We hypothesized that an epicardial approach with a novel nitinol catheter system capable of causing irreversible electroporation (IRE) with direct current (DC) could selectively and permanently destroy GP without collateral myocardial injury. METHODS: Acute studies and medium-term terminal studies (mean survival, 1137 days) were performed with seven dogs. In the acute studies, DC was used to target epicardial GP within the transverse sinus, oblique sinus, vein of Marshall, and right periaortic space. Successful electroporation was defined as the presence of ablative lesions in the GP without collateral myocardial damage. A four-point integer system was used to classify histologic changes in tissue harvested from the ablation sites. Atrial effective refractory period (AERP) was measured during the acute and medium-term studies. RESULTS: For six dogs in the medium-term studies, the postablation period was uneventful without complications. Lesions were successfully created at 20 of 21 sites (95.2%) with more than minimal myocardial damage in one dog. An increase in AERP occurred in both atria during the acute studies but was maintained only in the right atrium at medium-term follow-up (5032 milliseconds). No dog had damage to the esophagus, adjacent great arteries, or pulmonary veins. CONCLUSIONS: This proof-of-concept study suggests that safe, effective, and selective epicardial ablation of GP can be performed with DC by IRE with minimal collateral myocardial damage.

Diagnostic and therapeutic value of implantable loop recorder: A tertiary care center experience.

BACKGROUND: Implantable loop recorders (ILRs) are effective in achieving symptom-rhythm correlation. However, diagnostic yield in routine clinical practice is not well established. METHODS: Patients undergoing ILR implantation between April 2010 and May 2015 were included. All devices were enrolled in remote monitoring with automatic arrhythmia detection and P sense algorithms switched "ON." Symptom-rhythm correlation was assessed and changes in management were recorded. RESULTS: A total of 312 patients (57% male, age 53 ± 22 years; median CHADS2VaSc score  =  1) were included in this study. ILRs were implanted for evaluation of syncope in 206 (66.0%), presyncope in 23 (7.4%), unexplained palpitations in 51 (16.3%), and cryptogenic stroke in 27 (8.7%) patients. ILR monitoring yielded a diagnosis that changed management strategy in 146 (46.8%) patients over a median of 12 (1-42) months. Out of 163 (52.2%) patients with symptoms during the monitoring period, 100 (61.3%) had an arrhythmia. ILR was useful in ruling out an arrhythmic cause for symptoms in 63 (38.7%) patients. ILR results led to pacemaker implantation in 23 patients (7.4% overall and 11.2% of those with syncope) after median follow-up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, 11 of whom were initiated on oral anticoagulants. ILR results led to pacemaker implantation in 31 patients (9.9% overall and 19.0% of those with syncope) after median follow-up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, nine of whom were initiated on oral anticoagulants. Overall, ILR led to a change in management in 47% patients with a number needed to implant of 2.1 to change management. CONCLUSION: ILR monitoring is effective in achieving symptom-rhythm correlation and results in changes in management in nearly half of implanted patients. Additional studies are needed to evaluate cost efficacy of ILR and the optimal monitoring duration.