Inter-atrial septal balloon dilation to facilitate intracardiac echocardiography guided left atrial appendage occlusion.

INTRODUCTION: Percutaneous left atrial appendage occlusion (LAAO) is traditionally performed under general anesthesia with trans-esophageal echocardiography guidance. Intracardiac echo (ICE)-guided LAAO closure is increasing in clinical use. The ICE catheter is crossed into LA via interatrial septum (IAS) after the septum is dilated with LAAO delivery sheath. This step can be time-consuming and requires significant ICE catheter manipulation, which increases the risk of cardiac perforation. Pre-emptive septal balloon dilation can potentially help with ICE advancement in the LA. We sought to evaluate the effect of pre-dilation of the IAS with an 8 mm balloon on the ease of crossing the ICE catheter, fluoroscopy time for crossing, and overall procedure time. METHODS: The Piedmont LAAO registry was used to identify consecutive patients who underwent LAAO. The initial 25 patients in whom balloon dilation of the IAS was performed served as the experimental cohort, and the 25 consecutive patients before that in whom balloon dilation was not performed served as controls. In the experimental group, after a trans-septal puncture, the sheath was retracted to the right atrium with a guidewire still in the LA. An 8 × 40 mm Evercoss™ over the wire balloon was inflated across the IAS. The ICE catheter was then crossed into the LA using the fluoroscopic landmark of the guide wire and the ICE imaging. The sheath was then advanced along the ICE catheter via the transseptal puncture (TSP) and the procedure continued. Follow-up compputed tomography imaging was obtained at 4-8 weeks. RESULTS: Each group consisted of 25 patients. There were no significant differences in baseline characteristics. All procedures were performed successfully under conscious sedation and ICE guidance. There was a significant reduction in the overall procedure time, fluoroscopy time, and time for transseptal puncture to ICE in LA. There was no difference in the size of the acute residual interatrial shunt, as measured via ICE, or the size and presence of iatrogenic ASD at follow-up. CONCLUSION: Balloon dilation of TSP is safe and is associated with increased efficiency in ICE-guided LAAO procedures.

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 Network Meta-Analysis Comparing Osteoporotic Fracture among Different Direct Oral Anticoagulants and Vitamin K Antagonists in Patients with Atrial Fibrillation.

BACKGROUND: There are limited studies comparing the risk of osteoporosis and fractures between different direct oral anticoagulants (DOACs) and vitamin K antagonists (VKA) in non-valvular atrial fibrillation (AF). Using a network meta-analysis (NMA), we compared osteoporotic fractures among 5 different treatment arms, viz. dabigatran, rivaroxaban, apixaban, edoxaban, and VKA. METHODS: Ten studies, including 5 randomized control trials and 5 population-based studies, with a total of 321,844 patients (148,751 and 173,093 in the VKA and DOAC group, respectively) with a median follow-up of 2 years, were included. A Bayesian random-effects NMA model comparing fractures among the treatment arms was performed using MetInsight V3. Sensitivity analysis excluded studies with the highest residual deviances from the NMA model. RESULTS: The mean age of the patients was 70 years. The meta-analysis favored DOACs over VKA with significantly lower osteoporotic fracture (odds ratio [OR], 0.77; 95% credible interval [CrI], 0.70-0.86). The NMA demonstrated that fractures were significantly lower with apixaban compared with dabigatran (OR, 0.64; 95% CrI, 0.44-0.95); however, fractures were statistically similar between apixaban and rivaroxaban (OR, 0.84; 95% CrI, 0.58-1.24) and dabigatran and rivaroxaban (OR, 1.32; 95% CrI, 0.90-1.87). Based on the Bayesian model of NMA, the probability of osteoporotic fracture was highest with VKA and lowest with apixaban, followed by rivaroxaban, edoxaban, and dabigatran. CONCLUSIONS: The decision to prescribe anticoagulants in elderly patients with AF should be made not only based on thrombotic and bleeding risks but also on the risk of osteoporotic fracture; these factors should be considered and incorporated in contemporary cardiology practice.

Subcutaneous implantable cardioverter-defibrillator electrode fracture: Follow-up, troubleshooting, and evaluation.

The subcutaneous-implantable cardioverter-defibrillator (S-ICD) and its electrode were developed to avoid long-term complications of transvenous leads in the vasculature. We report a case of unexpected, inappropriate S-ICD shocks due to oversensing of high-amplitude, nonphysiologic, electrical noise artifacts that were not preceded by high-impedance alerts or sensing electrogram noise detections. Following explant, high-magnification X-ray imaging of the S-ICD electrode demonstrated partial fracture of the distal sensing conductor located near a short radius bend in the electrode at the electrode-header interface. Clinicians should be aware of a potential for fatigue failure fracture of the S-ICD electrode. Recommendations for systematic S-ICD follow-up and troubleshooting are discussed.

Rhythm Control of Persistent Atrial Fibrillation in Systolic Heart Failure: A Bayesian Network Meta-Analysis of Randomized Controlled Trials.

Background and Objectives: Persistent atrial fibrillation (PeAF) with heart failure (HF) arguably constitutes the sickest subset of atrial fibrillation (AF) patients. Methods: A systematic search was made in PubMed, Embase, and Scopus databases. Network meta-analysis (NMA) of PeAF patients with systolic HF comparing all-cause mortality, change in HF-related quality of life (QoL) and hospitalization due to heart failure (HHF) were performed among catheter ablation (CA) of AF, rate-controlling drugs (RCDs), anti-arrhythmic drugs (AADs), and atrio-ventricular nodal ablation (AVNA) using Bayesian random effect model. Results: Ablation strategies resulted significantly lower mortality than medical therapies (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.35 to 0.76). CA of AF was associated with lower trend of mortality (OR, 0.78; 95% credible interval [CrI], 0.08 to 7.63) in comparison to AVNA in the Bayesian NMA. Rhythm control strategies resulted significantly higher improvement of QoL than rate control strategies (mean difference [MD], -12.78; 95% CI, -21.26 to -4.31). Bayesian NMA showed that CA of AF was better than AAD (MD, -7.98; 95% CrI, -27.68 to 8.27), however ranked AVNA to be lowest. Ablation strategies provided significantly lower HHF than medical therapies (OR, 0.42; 95% CI, 0.30 to 0.58). Bayesian NMA showed that CA of AF performed not only better than AAD (OR, 0.33; 95% CrI, 0.09 to 1.3) to reduce HHF, but also than AVNA (OR, 0.20; 95% CrI, 0.00 to 4.76). Of note, RCD ranked lowest with regard to mortality and HHF. Conclusions: CA of AF remains the best strategy even for the sickest group of PeAF patients with systolic HF in regards to all-cause mortality, HF-related QoL and HHF.

Renal Dysfunction following Direct Current Cardioversion of Atrial Fibrillation: Incidence and Risk Factors.

INTRODUCTION: Emerging data suggest that cardioversion for atrial fibrillation (AF) may be associated with acute kidney injury (AKI). However, limited data are available regarding the incidence and risk factors for AKI after direct current cardioversion (DCCV) of AF. METHODS: All patients undergoing DCCV at Mayo Clinic between 2001 and 2012 for AF were prospectively enrolled in a database. All patients with serum creatinine (SCR) values pre- and post-cardioversion were reviewed for AKI, defined as a ≥25% decline in eGFR (estimated glomerular filtration rate) from baseline value within 7 days of the DCCV. RESULTS: Of the 6,427 eligible patients, 1,256 (19.5%) patients had pre- and post-DCCV SCR available and formed the cohort under study. The mean age was 70.4 (SD 11.7) years, and 67.3% were male. During the study period, 131 (10.4%) patients suffered from AKI following DCCV. AKI was independently associated with inpatient status (OR 26.79; 95% CI 3.69-194.52), CHA2DS2-VASc score (OR 1.25; 95% CI 1.11-1.41), prior use of diuretics (OR 1.59; 95% CI 1.03-2.46), and absence of CKD (OR 1.61; 95% CI 1.04-2.49), and was independent of the success of the DCCV. None of the patients required acute dialysis during the study outcome period. CONCLUSION: AKI following DCCV of AF is common, self-limited, and without the need for replacement therapies.

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.

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.

LV only pacing-mediated electrical storm with cardiac resynchronization therapy managed by simultaneous biventricular pacing.

Ventricular arrhythmia (VA) is a rare complication of cardiac resynchronization therapy (CRT). Little is known about ventricular proarrhythmia related to the pacing vector of CRT. This case report describes the elimination of ventricular arrythmia using biventricular pacing in a patient with VT-storm related to LV only pacing as part of the AdaptivCRT algorithm (Medtronic Inc). Simultaneous biventricular pacing was effective in eliminating polymorphic ventricular tachycardia. Changing the pacing vector is a noninvasive treatment strategy that should be considered to manage VA due to CRT.

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.

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.

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.

Safety of thoracic magnetic resonance imaging for patients with pacemakers and defibrillators.

BACKGROUND: During magnetic resonance imaging (MRI), cardiac implantable electronic device (CIED) leads can be antennae to focus energy onto myocardium, leading to heating and arrhythmias. Clinical data on thoracic MRI safety for patients with legacy devices are limited. OBJECTIVE: The purpose of this study was to identify patients undergoing thoracic MRI with legacy devices, compare the incidence of adverse events of those patients with control patients undergoing brain MRI with legacy devices, and compare paired cardiac troponin T (cTnT) values. METHODS: In this single-center study, we reviewed a prospectively collected database of patients with CIED undergoing MRI from January 25, 2008, through February 28, 2017. RESULTS: Of 952 patients (1290 scans), 120 patients (12.6%) underwent 134 thoracic MRI scans with legacy CIEDs (median [range] age 61.98 [21.24-86.96] years; male 71.1%). Median (range; interquartile range [IQR]) age of leads across devices was 3.5 (1.6-7.1; 5.5) years; implantable cardioverter-defibrillators (ICDs) were oldest (median [range; IQR], 3.7 [1.1-8.0; 6.9] years). No difference was observed in incidence of adverse events between groups. Paired cTnT values were compared for 19 patients (19 scans) with no difference between pre- and postimaging values. No significant difference was present in device setting values before and after MRI (mean follow-up 72.5 days). Incidence of adverse events was no different after adjustment for ICD coil number. CONCLUSION: Thoracic MRI is relatively safe in an institutional multidisciplinary program. It does not represent greater risk than brain MRI for patients with legacy CIEDs.

Radiofrequency ablation of the cavotricuspid isthmus for management of atrial flutter in patients with congenital heart disease after tricuspid valve surgery: A single-center experience.

BACKGROUND: Typical atrial flutter involving the cavotricuspid isthmus (CTI) is the most common reentrant arrhythmia in congenital heart disease and ablation is effective in its management. However, congenital heart disease patients often require surgical interventions on their tricuspid valve that utilize prosthetic material, making CTI ablation technically challenging. OBJECTIVE: To describe the techniques and outcomes of CTI ablation in the presence of prior tricuspid valve repair or replacement. METHODS: We included all patients who had undergone tricuspid valve repair utilizing an annuloplasty ring or tricuspid valve replacement who underwent CTI ablation for treatment of atrial arrhythmias between 2005 and 2017. Acute procedural success was defined as demonstration of bidirectional conduction block across the CTI. Long-term success was defined as lack of arrhythmia recurrence on monitoring or related symptoms. RESULTS: Sixteen patients met the inclusion criteria. Twelve (75%) patients had Ebstein's anomaly, 14 (88%) patients had a prosthetic tricuspid valve, and 2 (12%) patients had annuloplasty ring. Acute success was achieved in all cases, with no complications. Radiofrequency ablation was required on the ventricular side in 9 (56%) patients. In 1 case, ablation in the small cardiac vein was required. All patients remained free from atrial flutter during 18 months follow-up (range, 1-101 months). CONCLUSION: Our study demonstrates the safety and efficacy of catheter ablation of the CTI in the presence of a tricuspid annuloplasty ring or a prosthetic tricuspid valve. This may require ablation from the ventricular side of the valve to target atrial tissue rendered inaccessible as a result of tricuspid valve surgery.

Potentially modifiable factors of dofetilide-associated risk of torsades de pointes among hospitalized patients with atrial fibrillation.

PURPOSE: There is a significant variation in the clinical approach of initiation and dose adjustment of dofetilide in atrial fibrillation (AF). Excessive QT prolongation could predispose patients to torsades de pointes (TdP), which can be fatal. METHODS: We performed a retrospective case-control study at Mayo Clinic Rochester (January 1, 2003 to December 31, 2016). "TdP risk" cases were defined as patients on dofetilide therapy for AF with subsequent TdP or excessive QTc prolongation requiring dose reduction or discontinuation (N = 31). A control group was matched 1:1 with cases by age, gender, year of admission, and dofetilide dose (N = 31). RESULTS: Using multivariate regression analysis, independent predictors of TdP risk included baseline QTc exceeding recommendations (adjusted odd ratio [AOR] 4.57; P = 0.023); underlying AF with rapid ventricular rate (AOR 16.95; P = 0.004); and diuretic therapy for acute heart failure (AOR 8.42; P = 0.007). Poor inter-observer agreement was identified among QT interval measurement in patients with AF and rapid ventricular rate compared to those in rate controlled AF or sinus rhythm. TdP risk cases receiving diuretics for acute heart failure had a significant decline in creatinine clearance than controls, although serum electrolytes and replacement did not differ among the two groups. CONCLUSIONS: Excessive QTc prolongation and AF with rapid ventricular rate at time of dofetilide initiation (likely due to difficulty in measuring QT intervals), and diuretic therapy for acute heart failure were independent factors for dofetilide-related TdP risk. Based on these data, possible preventive strategies could be adapted for safety protocols among hospitalized patients.

Feasibility and safety of percutaneous epicardial access for mapping and ablation for ventricular arrhythmias in patients on oral anticoagulants.

PURPOSE: This study aimed to assess the risk of procedure-related complications of percutaneous epicardial access (EpiAcc) for radiofrequency catheter ablation (RFA) of ventricular arrhythmias (VAs) in patients chronically treated oral anticoagulants (OACs) with warfarin compared to those not on OACs. METHODS: We analyzed 205 patients (53 ± 16 years, 155 males) undergoing percutaneous EpiAcc as part of an RFA for VAs, and compared the outcome between patients chronically on OACs with warfarin (OAC group) and those without (non-OAC group). RESULTS: Forty-seven patients (23%) were chronically treated on OACs before their procedure. EpiAcc in patients on OAC (OAC group) was not associated with an increased risk of cardiac tamponade (11% vs. 6%, p = 0.238) compared to non-OAC group, but a higher risk of need for blood transfusion (17% vs. 6%; p = 0.013). With respect to the OAC group, the international normalized ratio (INR) on the day of the RFA was ≥ 2.0 in 9 patients (19%) and < 2.0 in the remaining 38 patients (81%). The rate of all complication and blood transfusion were similar between them (11% vs. 21%; p = 0.496, 11% vs. 18%; p = 0.600). CONCLUSION: Percutaneous EpiAcc in patients on chronic OAC with warfarin did not significantly increase the risk of cardiac tamponade, but was associated with a higher risk of need for blood transfusion. EpiACC in patients with an INR > 2.0 is reasonable in experienced hands when clinical indications are strong.