Predicting Permanent Pacemaker Implantation following Trans-catheter Aortic Valve Replacement: A Contemporary Meta-Analysis of 981,168 patients

Background

Heart block requiring permanent pacemaker (PPM) implantation is a relatively frequent complication of transcatheter aortic valve replacement (TAVR).

Objective

The purpose of this study was to perform a contemporary meta-analysis to provide an updated assessment of clinically useful predictors of PPM implantation post-TAVR.

Methods

Medline and EMBASE searches were performed to include all studies reporting PPM post-TAVR between 2015 and 2020. Pertinent data were extracted from the studies for further analysis. RevMan was used to create forest plots and calculate risk ratios (RRs).

Results

We evaluated 41 variables from 239 studies with a total of 981,168 patients. From this cohort, 17.4% received a PPM following TAVR. Strong predictors for PPM implant were right bundle branch block (RBBB) (RR 3.12; P <.001) and bifascicular block (RR 2.40; P = .002). Intermediate factors were chronic kidney disease (CKD) (RR 1.53; P <.0001) and first-degree atrioventricular block (FDAVB) (RR 1.44; P <.001). Weak factors (RR 1–1.50; P <.05) were male gender, age ≥80 years, body mass index ≥25, diabetes mellitus (DM), atrial fibrillation (AF), and left anterior fascicular block (LAFB). These factors along with increased left ventricular outflow tract (LVOT) area (>435 mm²) and/or aortic annulus diameter (>24.4 mm) were incorporated to propose a new scoring system to stratify patients into high- and low-risk groups.

Conclusion

Male gender, age ≥80 years, FDAVB, RBBB, AF, DM, CKD, Medtronic CoreValve, transfemoral TAVR, increased LVOT, and aortic annulus diameter were significant predictors of post-TAVR PPM implantation. Preprocedural assessment should consider these factors to guide clinical decision-making before TAVR. Validation of our scoring system is warranted.

Utilization and procedural adverse outcomes associated with Watchman device implantation

AIMS

The Food and Drug Administration (FDA) approval of the Watchman device [percutaneous left atrial appendage occlusion (LAAO)] has resulted in the widespread use of this procedure in many centres across the USA. We sought to estimate the nationwide utilization and frequency of adverse outcomes associated with Watchman device implantation. The objective of this study was to evaluate the Watchman device implantation peri-procedural complications and comparison of the results with the previous studies.

METHODS AND RESULTS

The National Inpatient Sample (NIS) was queried for all hospitalizations with a primary diagnosis of atrial fibrillation or atrial flutter during the year 2016 with percutaneous LAAO during the same admission (ICD-10 code-02L73DK). The frequency of peri-procedural complications, including mortality, procedure-related stroke, major bleeding requiring blood transfusion, and pericardial effusion, was assessed. We compared the complication rates with the published randomized controlled trials and the European Watchman registry. An estimated 5175 LAAO procedures were performed in 2016. The majority of procedures was performed in males (59.1%), age ≥75 years (58.7%), and White (83.1%). The overall complication rate was 1.9%. The in-hospital mortality was 0.29%. Pericardial effusion requiring pericardiocentesis was the most frequent complication (0.68%). Bleeding requiring transfusion was noted in 0.1% of device implants. The rates of post-procedure stroke and systemic embolism were 0% and 0.29%, respectively.

CONCLUSION

Percutaneous LAAO with the Watchman device in the USA is associated with low in-hospital complications and a similar safety profile to a recently published EWOLUTION cohort. The complication rates were lower than those reported in the major randomized clinical trials (RCTs). We report the frequency of peri-procedural complications of the LAAO using the Watchman device from the NIS database. We also compare the frequency of peri-procedural complications with the previously published RCTs and EWOLUTION cohort. Our findings are in concordance with findings from EWOLUTION cohort and compare favourably with RCTs.

The implementation of rifapentine and isoniazid (3HP) in two remote Arctic communities with a predominantly Inuit population, the Taima TB 3HP study

Background: The incidence of TB among Inuit is the highest in Canada. A significantly shorter latent TB infection (LTBI) treatment with rifapentine and isoniazid once weekly for 12 weeks (3HP) is now available in limited settings in Canada.Methods: A prospective open-label 2-year observational postmarketing study was conducted introducing 3HP for the first time in Canada in Iqaluit followed by a program rollout in Qikiqtarjuaq, Nunavut.Results: A total of 247 people were offered 3HP, 102 in the Iqaluit postmarketing study and 145 in the Qikiqtarjuaq program roll out. Although statistical significance was not reached, more people who started treatment completed treatment in the 3HP group (Iqaluit, 60/73 (82.2%) and Qikiqtarjuaq, 89/115 (77.4%)) than in the historical control 9INHgroup (306/420 = 72.9%) (p = 0.2). Most of the adverse events in 3HP treated patients were associated with mild discomfort but no disruption of normal daily activity. Not drinking alcohol was associated with increased 3HP completion (OR 13.33, 95% CI, 2.27-78.20) as was not taking concomitant medications (OR 7.19, 95% CI, 1.47-35.30).Conclusions: The present study supports the feasibility and safety profile of 3HP for the treatment of LTBI in Nunavut.

Seven-year retrospective study understanding the latent TB infection treatment cascade of care among adults in a low incidence country

Background

Prevention of TB is paramount to achieving elimination targets as recommended by the World Health Organization’s action framework for low incidence countries striving to eliminate TB. Although the rates of TB in Canada are low, understanding the latent TB infection (LTBI) cascade is paramount to identifying gaps in care and treatment barriers, thereby increasing the effectiveness of preventive strategies. The purpose of this study was to examine the LTBI cascade of care and identify barriers to treatment completion in adults referred from primary care to a regional tertiary care TB clinic in Ottawa, Canada.

Methods

Electronic medical records between January 2010 and December 2016 were reviewed retrospectively and an LTBI cascade of care was constructed from The Ottawa Hospital TB clinic and surrounding primary care clinics. A cohort of 2207 patients with untreated LTBI was used to ascertain the associations between demographic and clinical factors for both treatment non-initiation and non-completion using log-binomial univariable and multivariable regression models.

Results

Of 2207 patients with untreated LTBI who were seen in the clinic during the study period, 1771 (80.2%) were offered treatment, 1203 (67.9% of those offered) started treatment, and 795 (66.1% of those started) completed treatment. In multivariable analysis, non-initiation of treatment was associated with older age (adjusted risk ratio [aRR] 1.06 per 5-year increase, 95% CI: 1.03–1.08) and female gender (aRR 1.28, 95% CI: 1.11–1.47). Non completion of treatment was associated with referral from the TB Clinic back to the primary care team following initial consult (aRR 1.62, 95% CI: 1.35–1.94) and treatment with the standard of 9 months of Isoniazid (9H) compared to 4 months of Rifampin (4R) (aRR 1.45, 95% CI:1.20–1.74).

Conclusions

LTBI treatment completion was significantly decreased among patients who were referred back to primary care from the TB clinic. The 4R regimen resulted in more people completing LTBI treatment compared to 9H in keeping with a recently published RCT. Improved education, communication, and collaboration between tertiary care TB clinics and primary care teams may improve treatment completion rates and address the TB burden in low incidence communities in Canada.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10733-9.

Burden of arrhythmia in hospitalized HIV patients

Background

The improved life expectancy observed in patients living with human immunodeficiency virus (HIV) infection has made age‐related cardiovascular complications, including arrhythmias, a growing health concern.

Hypothesis

We describe the temporal trends in frequency of various arrhythmias and assess impact of arrhythmias on hospitalized HIV patients using the Nationwide Inpatient Sample (NIS).

Methods

Data on HIV‐related hospitalizations from 2005 to 2014 were obtained from the NIS database using International Classification of Diseases, 9th Revision (ICD‐9) codes. Data was further subclassified into hospitalizations with associated arrhythmias and those without. Baseline demographics and comorbidities were determined. Outcomes including in‐hospital mortality, cost of care, and length of stay were extracted. SAS 9.4 (SAS Institute Inc., Cary, NC) was utilized for analysis. A multivariable analysis was performed to identify predictors of arrhythmias among hospitalized HIV patients.

Results

Among 2 370 751 HIV‐related hospitalizations identified, the overall frequency of any arrhythmia was 3.01%. Atrial fibrillation (AF) was the most frequent arrhythmia (2110 per 100 000). The overall frequency of arrhythmias increased over time by 108%, primarily due to a 132% increase in AF. Arrhythmias are more frequent among older males, lowest income quartile, and nonelective admissions. Patients with arrhythmias had a higher in‐hospital mortality rate (9.6%). In‐hospital mortality among patients with arrhythmias decreased over time by 43.8%. The cost of care and length of stay associated with arrhythmia‐related hospitalizations were mostly unchanged.

Conclusions

Arrhythmias are associated with significant morbidity and mortality in hospitalized HIV patients. AF is the most frequent arrhythmia in hospitalized HIV patients.

A Systematic Review of the Cardiovascular Manifestations and Outcomes in the Setting of Coronavirus-19 Disease

The impact of coronavirus disease, 2019 (COVID-19), has been profound. Though COVID-19 primarily affects the respiratory system, it has also been associated with a wide range of cardiovascular (CV) manifestations portending extremely poor prognosis. The principal hypothesis for CV involvement is through direct myocardial infection and systemic inflammation. We conducted a systematic review of the current literature to provide a foundation for understanding the CV manifestations and outcomes of COVID-19. PubMed and EMBASE databases were electronically searched from the inception of the databases through 27 April 2020. A second literature review was conducted to include major trials and guidelines that were published after the initial search but before submission. The inclusion criteria for studies to be eligible were case reports, case series, and observation studies reporting CV outcomes among patients with COVID-19 infection. This review of the current COVID-19 disease and CV outcomes literature revealed a myriad of CV manifestations with potential avenues for treatment and prevention. Future studies are required to understand on a more mechanistic level the effect of COVID-19 on the myocardium and thus provide avenues to improve mortality and morbidity.

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.

Safety and efficacy of direct oral anticoagulants compared to Vitamin K antagonists postpercutaneous coronary interventions in patients with atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) and coronary artery disease (CAD) are commonly associated. Cotreatment with multiple antithrombotic agents can increase the risk of bleeding. We sought to evaluate patient-centered outcomes in patients with AF on double therapy with direct oral anticoagulants (DOACs) compared to patients with standard triple therapy, [a vitamin K antagonist (VKA) plus dual antiplatelet therapy].

METHODS

We performed a literature search of randomized controlled trials (RCTs) reporting outcomes of patients receiving double therapy with DOACs compared to triple therapy with VKAs in patients with AF undergoing percutaneous coronary intervention (PCI). Patient-centered outcomes were the International Society of Thrombosis and Hemostasis (ISTH) major or clinically relevant nonmajor bleeding (CRNB), all-cause mortality, major adverse cardiovascular events (MACE), stent thrombosis, myocardial infarction, and stroke.

RESULTS

Four RCTs (9602 patients) met our inclusion criteria. Compared to VKAs, DOACs were associated with significantly lower ISTH major bleeding/ CRNB (RR: 0.75, 95% CI: 0.67-0.82, P < .00001, I 2 = 11%). There were no statistically significant differences in the efficacy outcomes, including myocardial infarction (RR: 0.99, 95% CI :0.79-1.25, P = .96), stent thrombosis (RR: 0.97, 95% CI: 0.6-1.55, P = .89), ischemic stroke (RR: 0.76, 95% CI: 0.5-1.15, P = .19), all-cause mortality (RR: 1.06, 95% CI: 0.85-1.31, P = .61), and MACE (RR: 1.06, 95% CI: 0.91-1.22, P = .97).

CONCLUSION

Compared with triple therapy with VKAS, double therapy with DOACs is associated with a reduced risk of bleeding and is as effective in patients with AF undergoing PCI.

Validation of the Seegene RV15 multiplex PCR for the detection of influenza A subtypes and influenza B lineages during national influenza surveillance in hospitalized adults

Background. The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network (CIRN SOS) has been performing active influenza surveillance since 2009 (ClinicalTrials.gov identifier: NCT01517191). Influenza A and B viruses are identified and characterized using real-time reverse-transcriptase polymerase chain reaction (RT-PCR), and multiplex testing has been performed on a subset of patients to identify other respiratory virus aetiologies. Since both methods can identify influenza A and B, a direct comparison was performed.Methods. Validated real-time RT-PCRs from the World Health Organization (WHO) to identify influenza A and B viruses, characterize influenza A viruses into the H1N1 or H3N2 subtypes and describe influenza B viruses belonging to the Yamagata or Victoria lineages. In a subset of patients, the Seeplex RV15 One-Step ACE Detection assay (RV15) kit was also used for the detection of other respiratory viruses.Results. In total, 1111 nasopharyngeal swabs were tested by RV15 and real-time RT-PCRs for influenza A and B identification and characterization. For influenza A, RV15 showed 98.0 % sensitivity, 100 % specificity and 99.7 % accuracy. The performance characteristics of RV15 were similar for influenza A subtypes H1N1 and H3N2. For influenza B, RV15 had 99.2 % sensitivity, 100 % specificity and 99.8 % accuracy, with similar assay performance being shown for both the Yamagata and Victoria lineages.Conclusions. Overall, the detection of circulating subtypes of influenza A and lineages of influenza B by RV15 was similar to detection by real-time RT-PCR. Multiplex testing with RV15 allows for a more comprehensive respiratory virus surveillance in hospitalized adults, without significantly compromising the reliability of influenza A or B virus detection.

P2851Transvenous lead placement in the setting of venous obstruction: outcomes of tunneling technique versus venoplasty

Background

Venous stenosis is a well-recognized complication of transvenous leads when patients require lead revisions or device upgrade. In these cases, balloon venoplasty or alternative venous access with subcutaneous tunneling can be performed.

Purpose

Compare the outcomes of venoplasty vs. tunneling in patients requiring additional transvenous lead implantation.

Methods

A single center retrospective cohort study of all patients undergoing lead implantation/revision requiring venoplasty or tunneling from 2005–2017. Chi-squared and Wilcoxon Rank-Sum tests were used to compare categorical and continuous variables.

Results

Ninety five patients met our inclusion criteria (60 venoplasty & 35 tunneling). There was no difference in procedure success rates (p-value=0.98). Tunneling was associated with less fluoroscopy time but higher incidence of acute complications (0% vs. 23%, p-value=0.002) most requiring invasive intervention and/or blood product transfusion. Long term outcomes were comparable and related to lead failure or infection.

Outcomes for tunneling vs. venoplasty Variable Tunneling (n=35) Venoplasty (n=60) p-value Age Y 67 (23–84) 70 (29–91) 0.25 Male (%) 24 (69%) 41 (68%) 0.98 Number of existing leads 2.1 (1–4) 2.4 (0–4) 0.1 Age of oldest lead 7.0 (0–21) 7.2 (0–33) 0.73 Number of new leads 1.2 (1–3) 1.4 (1–3) 0.26 Fluoroscopy time (SD) min 29.2 (21.3) 39.7 (21.5) 0.012 Procedure success (%) 35 (100%) 55 (92%) 0.9 Acute complications (%) 8 (23%)1 0 (0%) 0.0002   Pocket hematoma/bleed 4 (11%)2   Hemothorax 2 (6%)3   Pericarditis 1 (3%)   Lead compromise 1 (3%) Follow up M 18 (0–76) 28 (0–98) N/A Long term lead issues (%) 6 (17%) 10 (17%) 0.95 Long term complication requiring intervention 4 (11%) 8 (13%) N/A Procedure success: functional lead placed as a result of venoplasty or tunneling. 1Two patients required blood products. 2Two patients required invasive intervention. 3One patient required chest tube and the other ICU admission.

Conclusions

Balloon venoplasty is associated with similar rates of success and a less incidence of acute complications when compared subcutaneous tunneling.

Acknowledgement/Funding

NIH T32 Training Grant HL07111-40

Frequency of in-hospital adverse outcomes and cost utilization associated with cardiac resynchronization therapy defibrillator implantation in the United States

BACKGROUND

The utilization of cardiac resynchronization therapy defibrillator (CRT-D) has increased significantly, since its initial approval for use in selected patients with heart failure. Limited data exist as for current trends in implant-related in-hospital complications and cost utilization. The aim of our study was to examine in-hospital complication rates associated with CRT-D and their trends over the last decade.

METHODS AND RESULTS

Using the Nationwide Inpatient Sample, we estimated 378 248 CRT-D procedures from 2003 to 2012. We investigated common complications, including mechanical, cardiovascular, pericardial complications (hemopericardium, cardiac tamponade, or pericardiocentesis), pneumothorax, stroke, vascular complications (consisting of hemorrhage/hematoma, incidents requiring surgical repair, and accidental arterial puncture), and in-hospital deaths described with CRT-D, defining them by the validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code. Mechanical complications (5.9%) were the commonest, followed by cardiovascular (3.6%), respiratory failure (2.4%), and pneumothorax (1.5%). Age (≥65 years), female gender (OR, 95% CI; P value) (1.08, 1.03-1.13; 0.001), and the Charlson score ≥3 (1.52, 1.45-1.60; <0.001) were significantly associated with increased mortality/complications.

CONCLUSIONS

The overall complication rate in patients undergoing CRT-D has been increasing in the last decade. Age (≥65), female sex, and the Charlson score ≥3 were associated with higher complications. In patients who underwent CRT-D implantation, postoperative complications were associated with significant increases in cost.

Outcomes of repeated transvenous lead extraction

INTRODUCTION

The outcomes of repeated cardiovascular implantable electronic device (CIED) lead extraction have not been well studied. We sought to determine the indications, outcomes, and safety of repeated lead extraction procedures.

METHODS

This retrospective study was conducted using data from two medical centers, including 38 patients who had undergone two or more lead extraction procedures compared to 439 patients who had a single procedure. The electronic medical records and procedural databases were reviewed to determine the indications, procedural characteristics, and outcomes. The outcomes of the first procedure were compared to the outcomes of subsequent procedures.

RESULTS

The 5-year cumulative probability of a repeated extraction procedure was 11% (95% confidence interval, 7%-15%). In 439 patients who underwent single lead extractions, 72% had device and lead related infections as the procedure indication compared to 39% for 38 patients who underwent repeated extraction (P < 0.001). The mean duration from device reimplant to repeated extraction procedures was 63 ± 48 months. Ninety-eight percent of the leads were removed completely in repeated procedures, similar to the 95% success rate of the first procedure (P = 0.51). There was no significant difference in major complication rate in the first or repeated extractions (2.6% vs 5.2%, P = 0.79).

CONCLUSIONS

Repeated transvenous lead extraction is not uncommon. It had a high success rate comparable to that of the initial procedure and was not associated with an increased incidence of adverse events.

Safety of magnetic resonance imaging in patients with legacy pacemakers and defibrillators and abandoned leads

BACKGROUND

During magnetic resonance imaging (MRI), abandoned leads may act as antennae that result in tissue heating and arrhythmia induction.

OBJECTIVE

The purpose of this study was to assess the safety of MRI in patients with abandoned leads, with the addition of cardiac troponin T (cTnT) assessment to screen for myocardial damage.

METHODS

We reviewed our prospectively collected database of patients with cardiovascular implantable electronic devices (CIEDs) undergoing MRI between 2008 and 2017 at Mayo Clinic, Rochester, MN, and selected patients who had abandoned leads. We compared the adverse events in this population with an age, sex, and site of MRI-matched cohort of patients selected from this database. We evaluated paired (before/after) cTnT values using MRI in these patients.

RESULTS

Of 952 patients, 80 (8.4%) underwent 97 MRI scans with CIEDs in situ with 90 abandoned leads in place during the scans. The median age was 66 years (interquartile range 22.3 years) 66.1 years (interquartile range, Q1,Q3: 53.6, 75.9) with 66.3% (53 patients) men. There was no clinical or electrical evidence of CIED dysfunction, arrhythmias, or pain. Paired samples for the measurement of cTnT values were available in 40 patients undergoing 44 MRI examinations. The mean difference between the pre- and postimaging values was -0.002 ± 0.006 ng/mL (interquartile range 0). There was no difference after adjustment for total number of leads per patient and total number of implantable cardioverter-defibrillator coils.

CONCLUSION

There was no evidence of myocardial injury as measured by paired cTnT. The risk of MRI with abandoned leads appears low, suggesting a favorable risk-benefit profile in patients with CIEDs and abandoned leads who are considered for MRI.

Pericardial effusion following drain removal after percutaneous epicardial access for an electrophysiology procedure

OBJECTIVES

To determine the frequency and predictors of pericardial effusion following epicardial sheath removal.

BACKGROUND

Pericardial effusion can occur following cardiac surgical or interventional procedures including percutaneous epicardial access (EpiAcc), which is increasingly used as part of electrophysiology ablation procedures.

METHODS

A retrospective analysis of the Mayo Clinic comprehensive electronic medical record was performed from all patients who underwent planned EpiAcc as part of an electrophysiology ablation procedure between January 1, 2004 and June 30, 2013.

RESULTS

Of 144 patients (mean age 51.3 ± 15.5 years, 68% male) who underwent planned EpiAcc as part of an electrophysiology ablation (95.8% pericardial access success rate), seven (4.9%) developed a postoperative pericardial effusion requiring repeat EpiAcc. Inferior access was utilized in 74 (51.4%) patients. Patients with pericardial effusion tended to be younger (41.1 years vs 51.8 years, P = 0.08) and were more likely to have undergone inferior approach access (85.7% vs 49.6%, P = 0.06) than those who did not develop postoperative pericardial effusion. Seventy-one percent of patients with postoperative pericardial effusion versus 32.1% of patients without postoperative pericardial effusion had a preprocedure ejection fraction ≥55% (P = 0.03). There were no procedural-related deaths, and no difference in mortality between groups.

CONCLUSIONS

Postoperative pericardial effusion requiring repeat access/drainage was relatively infrequent, occurring in 4.9% of patients shortly after epicardial procedures. While the majority occur early and therefore require close observation, some patients may present in a delayed manner.

Electrophysiologic characteristics of ventricular arrhythmias arising from the aortic mitral continuity-potential role of the conduction system

INTRODUCTION

Catheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown.

METHODS

Procedural records of 528 consecutive patients undergoing ablation of VA at Mayo Clinic, Rochester, MN, were reviewed. The electrocardiographic and electrophysiologic characteristics of patients with successful ablation at the AMC were analyzed to characterize the underlying arrhythmogenic substrate.

RESULTS

Of the 21 patients (mean age 53.2 ± 13.4 years, 47.6% male) who underwent ablation of VA at the AMC with acute success, prepotentials (PPs) were found at the ablation sites preceding the ventricular electrogram (VEGM) during arrhythmias in 13 (61.9%) patients and during sinus rhythm in 7 (53.8%) patients. VAs with PPs were associated with a significantly higher burden of premature ventricular complexes (PVCs; 26.1 ± 10.9% vs. 14.9 ± 10.1%, P = 0.03), shorter VEGM to QRS intervals (9.0 ± 28.5 milliseconds vs. 33.1 ± 8.8 milliseconds, P = 0.03), lower pace map scores (8.7 ± 1.6 vs. 11.4 ± 0.8, P = 0.001), and a trend toward shorter V-H intervals during VA (32.1 ± 38.6 milliseconds vs. 76.3 ± 11.1 milliseconds, P = 0.06) as compared to those without PP. A strong and positive correlation was found between V-H interval and QRS duration during arrhythmia in those with PPs (B = 2.11, R(2) = 0.97, t = 13.7, P < 0.001) but not in those without PPs.

CONCLUSION

Local EGM characteristics and relative activation time of the His bundle suggest the possibility of conduction tissue as the origin for VA arising from the fibrous AMC. Specific identification and targeting of PPs when ablating VAs at this location may improve procedural success.

Obesity does not increase complication rate of percutaneous epicardial access

INTRODUCTION

Percutaneous 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 RESULTS

We 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).

CONCLUSION

Percutaneous 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.

Renal nerve stimulation for the treatment of neurocardiogenic syncope

Neurocardiogenic syncope is a common disorder resulting from a transient increase in vagal tone and central sympathetic withdrawal leading to varying degrees of vasodilation and bradycardia. Hence an effective treatment should address both the bradycardia and vasodilation. We hypothesized that, stimulation of the renal sympathetic nerves using high frequency stimulation in the renal vein will increase blood pressure through an increase in sympathetic output and therefore may be of use in treating neurocardiogenic syncope. Renal nerve stimulation was performed under Isoflurane anesthesia in 5 dogs and 1 baboon using a 4mm quadripolar catheter in unilateral renal vein using a Grass stimulator (square wave, 120V, 900pps, 30-200s). A consistent increase in arterial systolic BP [mean (SD) pre- vs peak-stimulation 103 (±27) vs. 122 (±41) mmHg] and diastolic BP [69 (±19) vs. 82 (±31) mmHg] was noted during stimulation. Median interquartile change in systolic BP was 11 (5-22) mmHg and 6 (-2-16) mmHg in diastolic BP. To conclude, renal nerve stimulation through the renal vein increased BP. Potential applications include treatment of vasodilatory component of neurocardiogenic syncope and confirmation of successful renal nerve ablation for the treatment of hypertension.

Utility and safety of temporary pacing using active fixation leads and externalized re-usable permanent pacemakers after lead extraction

AIMS

After extraction of an infected cardiac implantable electronic device (CIED) in a pacemaker-dependent patient, a temporary pacemaker wire may be required for long periods during antibiotic treatment. Loss of capture and under sensing are commonly observed over time with temporary pacemaker wires, and patient mobility is restricted. The use of an externalized permanent active-fixation pacemaker lead connected to a permanent pacemaker generator for temporary pacing may be beneficial because of improved lead stability, and greater patient mobility and comfort. The aim of this study was to investigate the efficacy and safety of a temporary permanent pacemaker (TPPM) system in patients undergoing transvenous lead extraction due to CIED infection.

METHODS AND RESULTS

Of 47 patients who underwent lead extraction due to CIED infection over a 2-year period at our centre, 23 were pacemaker dependent and underwent TPPM implantation. A permanent pacemaker lead was implanted in the right ventricle via the internal jugular vein and connected to a TPPM generator, which was secured externally at the base of the neck. The TPPM was used for a mean of 19.4 ± 11.9 days (median 18 days, range 3-45 days), without loss of capture or sensing failure in any patient. Twelve of 23 patients were discharged home or to a nursing facility with the TPPM until completion of antibiotic treatment and re-implantation of a new permanent pacemaker.

CONCLUSION

External TPPMs are safe and effective in patients requiring long-term pacing after infected CIED removal.

Gender difference in coronary sinus anatomy and left ventricular lead pacing parameters in patients with cardiac resynchronization therapy

BACKGROUND

 Recent studies have suggested better outcomes from cardiac resynchronization therapy (CRT) in women. Gender differences in coronary sinus (CS) anatomy and left ventricular (LV) lead parameters in patients undergoing CRT, however, have not been well studied.

METHODS AND RESULTS

 Two hundred and twenty-three consecutive patients, undergoing CRT at the University of California in San Diego Medical Center from 2003 to 2011 were included in this study. The location of the LV lead was assessed on coronary venography and chest X-ray recorded at the time of device implantation. Optimal LV lead position was defined as either mid-lateral or posterolateral LV wall. The relationship between LV lead position (optimal or non-optimal position) and LV lead parameters at completion of implant were compared between genders. No statistically significant gender differences were noted in baseline characteristics. LV lead implantation was successful in 217 patients (97.3%). Lateral or posterolateral CS branches were unavailable in more women than men (26.3% vs. 10.8%, P=0.011). Women had a higher LV lead pacing threshold than men (P=0.003) and gender was an independent risk factor of high LV lead pacing threshold (P=0.008).

CONCLUSIONS

 Women had an anatomical disadvantage for LV lead placement and had higher LV lead pacing threshold compared to men. Implanting physicians should be aware of gender differences during LV lead placement in order to maximize CRT benefits. 

Adaptive response in frogs chronically exposed to low doses of ionizing radiation in the environment

Using the micronucleus assay, decreased levels of DNA damage were found after high dose ionizing radiation exposure of liver cells taken from frogs inhabiting a natural environment with above-background levels of ionizing radiation, compared to cells taken from frogs inhabiting background areas. The data obtained from a small number of animals suggest that stress present in the above-background environment could induce an adaptive response to ionizing radiation. This study did not reveal harmful effects of exposure to low levels of radioactivity. On the contrary, stress present in the above-background area may serve to enhance cellular defense mechanisms.