Effect of ElectroMagnetic interference from SmartPHone on cardiac ImplaNtable electronic device (EMI-PHONE study).

Background: Smartphone can emit two types of electromagnetic waves, static field and dynamic field. Evidence showed the interference from phones to cardiac implantable electronic devices (CIEDs). The smartphones and CIEDs are reportedly better designed to reduce electromagnetic interference (EMI). Methods: 80 consecutive subjects with CIEDs were recruited and tested for EMI. Subject was tested with three different smartphones (Nokia 3310, Iphone 7, and Samsung 9S). Phone was attached to chest wall at 0 cm at generator site, at atrial lead level, and at ventricular lead level. During the tests, real-time interrogations were performed to detect any EMI from smartphone in standby mode, and during calling-in and out for 30 s. After the tests, post-test interrogations were performed to detect any parameter change. Adverse events including pacemaker inhibition, false ICD shock, CIEDs device malfunction, and urgent electrophysiologist consultations were recorded. Results: 80 subjects (mean age 70.5-year-old, 50% male) recruited in the study, all completed the testing protocol. The most common type of CIEDs tested was pacemaker (N = 56, 70%), followed by ICD (N = 16, 20%), and CRT (N = 8, 10%). Most patients (N = 62, 77.5%) had more than one lead implanted. The mean year of implantation was 5.2±2.8 (devices were implanted from 2008 to 2019). Of all the tests performed, there was no EMI or adverse events observed. Conclusion: Current generation of smartphones has no EMI effect on CIEDs in our study and can be used safely with less concern about adverse events including pacemaker inhibition, inappropriate ICD shock, and CIEDs device malfunction.

Transvenous Lead Extraction (TLE) Procedure: Experience from a Tertiary Care Center in Thailand.

BACKGROUND: Transvenous Lead Extraction (TLE) is a standard treatment for some late Cardiac Implantable Electronics Device (CIED) complications. The outcome of transvenous lead extraction procedure in Thailand is not robust. METHODS: A Single-center retrospective cohort of TLE procedures performed at Ramathibodi hospital between January 2008 and December 2020 was studied. RESULTS: There were 157 leads from 105 patients who underwent lead removal procedure during the specified period. Data analysis was performed from 79 TLE patients due to incomplete data and lead explant procedure of the excluded subjects. Mean patients' age was 57.7 ± 18.7 years, with 70.9% male. There were 82 pacemaker leads, 35 ICD leads, and 5 CS leads (mean number of leads were 1.54 ± 0.66 per patient), with mean implanted duration of 87.8 ± 68.2 months. Main indication for TLE was infection-related, which accounted for 67.1% of the cases. Overall clinical success rate was 97.5%. Mean operative time was 163.8 ± 69.5 min. Major complications occurred in 4 patients (5.1%) with one in-hospital mortality from severe sepsis. CONCLUSION: TLE using laser sheath and rotating mechanical sheath for transvenous lead extraction is effective and safe, even outside high-volume center.

Dynamic voltage threshold adjusted substrate modification technique for complex atypical atrial flutters with varying circuits.

BACKGROUND: Atypical atrial flutter (AFL) is common in patients with postsurgical atrial scar, with macro- or microscopic channels in the scar acting as substrate for reentry. Heterogeneous atrial scarring can cause varying flutter circuits, which makes mapping and ablation challenging, and recurrences common. AIM: We hypothesize that dynamically adjusting voltage thresholds can identify heterogeneous atrial scarring, which can then be effectively homogenized to eliminate atypical AFLs. METHODS: We studied consecutive patients who presented to Electrophysiology laboratory for atypical AFL ablation with history of atriotomy and included the patients with multiple, varying flutter circuits during mapping in our study. We excluded patients with stable flutter circuit that was sustained and could be localized using traditional entrainment and activation mapping strategy. In the included patients, we performed detailed high-density voltage map of the atrium of interest. We adjusted voltage thresholds as needed to identify heterogeneity and channels in the scarred regions. A thorough scar homogenization was performed with irrigated smart-touch ablation catheter. Re-inducibility of tachycardia, and immediate and long-term outcomes were studied. RESULTS: Of five studied cases, one was female; age 66 ± 10 years. All five had prior surgical substrate. All the patients had multiple flutter morphologies, which varied as we mapped the AFL. After scar homogenization, tachycardia was not inducible in any patient. No recurrence of flutter was noted during a mean follow-up duration of 450 ± 27 days. CONCLUSION: High-density voltage mapping and homogenization of the scar can be an effective strategy in eliminating complex scar-mediated atypical AFL with multiple circuits.

Esophageal Thermal Injury Following Cryoballoon Ablation for Atrial Fibrillation.

OBJECTIVES: This study evaluated the rate and predictors of endoscopically detected esophageal thermal lesions (EDEL) in patients who underwent cryoballoon atrial fibrillation (AF) ablation (CBA). BACKGROUND: EDEL is a known complication of catheter ablation for AF and is the inciting factor for atrial esophageal fistula formation. METHODS: An observational study was conducted of patients with AF presenting for CBA. Pre-procedural magnetic resonance imaging was used to retrospectively evaluate the distance between the atrial endocardium and the esophageal lumen (AED). Intraprocedural esophageal luminal temperature and balloon temperatures were recorded. All patients underwent upper endoscopy (EGD) 24 h post-ablation. Clinical, anatomical, and ablation parameters were analyzed using logistic regression for association with thermal injury. RESULTS: A total of 95 patients (37% women; 71% paroxysmal AF) were included in the study. Esophageal thermal injury was detected on EGD in 21 patients (22%). EDEL was mostly mild (20 of 21 patients) and severe in only 1 of 21 patients. Univariate logistic regression identified gastroesophageal reflux disease to be associated with increased risk of thermal injury (odds ratio [OR]: 3.2; 95% confidence interval [CI]: 1.00 to 10.46; p = 0.04), whereas a wider AED was protective (OR: 0.16; 95% CI: 0.05 to 0.515; p = 0.002). Esophageal wall thickness was also protective (OR: 0.04; 95% CI: 0.002 to 0.864; p = 0.04). In multivariate analysis, only AED (OR: 0.22; 95% CI: 0.06 to 0.77; p = 0.018) and obesity (OR: 4.63; 95% CI: 1.13 to 18.97; p = 0.033) were associated with EDEL. Esophageal luminal temperature, number, and duration of cryoballoon applications and balloon temperature were not predictors of EDEL. CONCLUSIONS: EDEL following CBA occurred in 22% of patients and was mostly mild. Obesity and atrioesophageal distance were independently associated with increased risk.

Modes of death and clinical outcomes in adult patients with hypertrophic cardiomyopathy in Thailand.

BACKGROUND: There are limited data about modes of death and major adverse cardiovascular events (MACEs) in patients with hypertrophic cardiomyopathy (HCM) in South East Asian population. The aim of the study was to examine modes of death and clinical outcomes in Thai patients with HCM. METHODS: Between January 1, 2009 and December 31, 2013, 166 consecutive patients with HCM diagnosed in our institution were evaluated. Five patients were excluded because of non-Thai ethnic groups (n = 3) and diagnosis of myocardial infarction at initial presentation documented by coronary angiography (n = 2). The final study population consisted of 161 patients with HCM. HCM-related deaths included: (1) sudden cardiac death (SCD) - death due to sudden cardiac arrest or unexpected sudden death; (2) heart failure - death due to refractory heart failure; or (3) stroke - death due to embolic stroke associated with atrial fibrillation. MACEs included: (1) SCD, sudden unexpected aborted cardiac arrest, fatal, or nonfatal ventricular arrhythmia (ventricular fibrillation or sustained ventricular tachycardia); (2) heart failure (fatal or non-fatal), or heart transplantation; or (3) stroke - fatal or non-fatal embolic stroke associated with atrial fibrillation. RESULTS: One hundred and sixty-one Thai patients with HCM (age 66 ± 16 years, 58% female) were enrolled. Forty-two patients (26%) died over a median follow-up period of 6.8 years including 25 patients (16%) with HCM-related deaths (2%/year). The HCM-related deaths included: heart failure (52% of HCM-related deaths; n = 13), SCD (44% of HCM-related deaths; n = 11), and stroke (4% of HCM-related deaths, n = 1). The SCDs occurred in 6.8% of patients (1%/year). Eighty-four major MACEs occurred in 65 patients (41, 5%/year). The MACEs included: 40 heart failures in which 2 patients underwent heart transplants; 22 SCDs and nonfatal ventricular arrhythmias; and 22 fatal or nonfatal strokes. CONCLUSIONS: The most common mode of death in adult patients with HCM in Thailand was heart failure followed by SCD. About one-third of the patients experiencing heart failure died during the 6.8 years of follow-up. SCDs occurred in 7% of patients (1%/year), predominantly in the fourth decade or later.

B-type natriuretic peptide is a major predictor of ventricular tachyarrhythmias.

BACKGROUND: The cost-effective use of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death requires identification of patients at risk for ventricular tachyarrhythmias, not just for total mortality. OBJECTIVE: To determine whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) or B-type natriuretic peptide (BNP) are independent predictors of ventricular arrhythmias in patients receiving primary prevention ICDs. METHODS: One hundred sixty-one patients with NT-proBNP levels and 403 patients with BNP levels at the time of ICD implantation were retrospectively assessed for the occurrence of first appropriate ICD therapy and mortality. RESULTS: In multivariable Cox proportional hazards regression analysis, NT-proBNP or BNP levels in the upper 50th percentile were the strongest predictor of ICD therapy after adjustment for sex, age, left ventricular ejection fraction, New York Heart Association class, history of coronary artery disease, blood urea nitrogen, creatinine clearance, and history of atrial fibrillation (hazard ratio [HR] 5.75, P < .001 for NT-proBNP; HR 3.40, P = .01 for BNP). Patients were divided into quartiles on the basis of NT-proBNP or BNP levels. The adjusted HR for ICD therapy in the highest and second highest quartiles of NT-proBNP levels (HR 12.9, P < .001, and HR 4.6, P = .03, respectively) were higher than the adjusted HR for total mortality in these 2 quartiles (HR 3.4, P = .021 and HR 2.3, P = .13, respectively). Similarly, the adjusted HR for ICD therapy in the highest and second highest quartiles of BNP levels (HR 4.74, P = .01 and HR 2.17, P = .04, respectively) were higher than the adjusted HR for total mortality in these 2 quartiles (HR 3.05, P = .01 and HR 1.07, P = .3, respectively). CONCLUSION: In this study, elevated baseline NT-proBNP and BNP levels are independently associated with the risk for ventricular tachyarrhythmias, which significantly exceeds the risk for total mortality, in multivariable analysis.