Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms:results from a multicentre long-term registry

AIMS : To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs). METHODS AND RESULTS: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03]. CONCLUSION : Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences

Analysis of cardiovascular mortality, bleeding, vascular and cerebrovascular events in patients with atrial fibrillation vs. sinus rhythm undergoing transfemoral Transcatheter Aortic Valve Implantation (TAVR)

Abstract Background Transcatheter aortic valve replacement (TAVR) has been demonstrated to be an established therapy for high-risk, inoperable patients with severe symptomatic aortic valve stenosis. For patients with moderate surgical risk, TAVR is equivalent to conventional aortic valve surgery. However, atrial fibrillation (AF) is also present in many of these patients, thus requiring post-implantation oral anticoagulation therapy in addition to the inhibition of thrombocyte aggregation, which poses the risk of bleeding complications. The aim of our work was to investigate the influence of AF on mortality and the occurrence of bleeding, vascular and cerebrovascular complications related to TAVR according to the VARC-2 criteria. Methods Two hundred eighty-three patients who underwent TAVR between March 2010 and April 2016 were retrospectively examined. In total, 257 patients who underwent transfemoral access were included in this study. The mean patient age was 81 ± 6 years, 54.1% of the patients were women, and 42.4% had pre-interventional AF. Results Compared to patients with sinus rhythm (SR, n = 148), patients with AF (n = 109) had an almost three-fold higher incidence of major vascular complications (AF 14.7% vs. SR 5.4%, p = 0.016) and life-threatening bleeding (AF 11.9% vs. SR 4.1%, p = 0.028) during the first 30 post-procedural days. However, the rate of cerebrovascular complications (AF 3.7% vs. SR 2.7%, p = 0.726) did not significantly differ between the two groups. Overall mortality was significantly higher in patients with AF during the first month (AF 8.3% vs. SR 2.0%, p = 0.032) and the first year (AF 28.4% vs. SR 15.3%; p = 0.020) following TAVR. Conclusion Patients with AF had significantly more severe bleeding complications after TAVR, which were significantly related to mortality. Future prospective randomized studies must clarify the optimal anticoagulation therapy for patients with AF after TAVR. Trial registration DRKS00011798 on DRKS (Date 17.03.2017)

Single-lead ECG recordings including Einthoven and Wilson leads by a Smartwatch

Background: Smartwatches that are able to record a bipolar ECG and Einthoven leads were recently described. Nevertheless, for detection of ischemia or other cardiac diseases more leads are required, especially Wilson's chest leads. Objectives: Feasibility study of six single-lead smartwatch (Apple Watch Series 4) ECG recordings including Einthoven (I, II, III) and Wilson-like pseudo-unipolar chest leads (Wr, Wm, Wl). Methods: In 50 healthy subjects (16 males; age: 36 $\pm$ 11 years, mean $\pm$ SD) without known cardiac disorders, a standard 12-lead ECG and a six single-lead ECG using an Apple Watch Series 4 were performed under resting conditions. Recording of Einthoven I was performed with the watch on the left wrist and the right index finger on the crown, Einthoven II was recorded with the watch on the left lower abdomen and the right index finger on the crown, Einthoven III was recorded with the watch on the left lower abdomen and the left index finger on the crown. Wilson-like chest leads were recorded corresponding to the locations of V1 (Wr), V4 (Wm) and V6 (Wl) in the standard 12-lead ECG. Wr was recorded in the fourth intercostal space right parasternal, Wm was recorded in the fifth intercostal space on the midclavicular line, and Wl was recorded in the fifth intercostal space in left midaxillary line. For all Wilson-like chest lead recordings, the smartwatch was placed on the described three locations on the chest, the right index finger was placed on the crown and the left hand encompassed the right wrist. Both hands and forearms also had contact to the chest. Three experienced cardiologists were independently asked to allocate three bipolar limb smartwatch ECGs to Einthoven I–III leads, and three smartwatch Wilson-like chest ECGs (Wr, Wm, Wl) to V1, V4 and V6 in the standard 12-lead ECG for each subject. Results: All 300 smartwatch ECGs showed a signal quality useable for diagnostics with 281 ECGs of good signal quality (143 limb lead ECGs (95%), 138 chest lead ECGs (92%). Nineteen ECGs had a moderate signal quality (7 limb lead ECGs (5%), 12 chest lead ECGs (8%)). One-hundred percent of all Einthoven and 92% of all Wilson-like smartwatch ECGs were allocated correctly to corresponding leads from 12-lead ECG. Forty-six subjects (92%) were assigned correctly by all cardiologists. Allocation errors were due to similar morphologies and amplitudes in at least two of the three recorded Wilson-like leads. Despite recording with a bipolar smartwatch device, morphology of all six leads was identical to standard 12-lead ECG. In two patients with acute anterior myocardial infarction, all three cardiologists recognized the ST-elevations in Wilson-like leads and assumed an occluded left anterior descending coronary artery correctly. Conclusion: Consecutive recording of six single-lead ECGs including Einthoven and Wilson-like leads by a smartwatch is feasible with good ECG signal quality. Thus, this simulated six-lead smartwatch ECG may be useable for the detection of cardiac diseases necessitating more than one ECG lead like myocardial ischemia or more complex cardia arrhythmias

Recording of bipolar multichannel ECGs by a smartwatch

$\it Aims:$ Feasibility study of accurate three lead ECG recording (Einthoven I, II and III) using an Apple Watch Series 4. $\it Methods:$ In 50 healthy subjects (18 male; age: 40 $\pm$ 12 years) without known cardiac disorders, a 12-lead ECG and three bipolar ECGs, corresponding to Einthoven leads I, II and III were recorded using an Apple Watch Series 4. Einthoven I was recorded with the watch on the left wrist and the right index finger on the crown, Einthoven II with the watch on the left lower abdomen and the right index finger on the crown, Einthoven III with the watch on the left lower abdomen and the left index finger on the crown. Four experienced cardiologists were independently asked to assign the watch ECGs to Einthoven leads from 12-lead ECG for each subject. $\it Results:$ All watch ECGs showed an adequate signal quality with 134 ECGs of good (89%) and 16 of moderate signal quality (11%). Ninety-one percent of all watch ECGs were assigned correctly to corresponding leads from 12-lead ECG. Thirty-nine subjects (78%) were assigned correctly by all cardiologists. All assignment errors occurred in patients with similar morphologies and amplitudes in at least two of the three recorded leads. Erroneous assignment of all watch ECGs to leads from standard ECG occurred in no patient. $\it Conclusion:$ Recording of Einthoven leads I-III by a smartwatch is accurate and highly comparable to standard ECG. This might contribute to an earlier detection of cardiac disorders, which are associated with repolarization abnormalities or arrhythmias

Left atrial enlargement and clinical considerations in patients with or without a residual interatrial shunt after closure of the left atrial appendage with the WATCHMAN™-device

Abstract Background Interventional closure of the left atrial appendage (LAA) in patients with non-valvular atrial fibrillation, high thromboembolic and bleeding risk or bleeding history is an alternative therapeutic strategy to oral anticoagulation. It is not known if the exclusion of the LAA from the blood circulation affects the left atrial volume (LAV) and consequently its prognostic value or the circulatory performance of the heart in humans. Methods We aimed to prospectively assess potential changes in baseline LAV, left ventricular ejection fraction (LVEF), NT-proBNP-level and the covered distance in the 6-min walk-test 6 weeks and 6 months after LAA closure with the WATCHMAN™ device. We used serial 3-dimensional transthoracic and transesophageal echocardiography to assess LAV, residual interatrial shunt and device performance in 58 consecutive patients with successful LAA closure. Results Accurate 3D–echocardiographic data for LAV measurements were evaluable for 51 (91%) patients. Maximum LAV (LAVmax) at baseline was 102.8 ± 30.8 ml and increased significantly to 107.7 ± 32.8 ml after 6 weeks (p < 0.01) and 113.5 ± 34.2 ml after 6 months (p < 0.01). Minimal LAV (LAVmin) increased from 76.9 ± 29.5 ml at baseline to 81.8 ± 30.2 ml after 45 days (p < 0.01) and 82.1 ± 33.3 ml after 6 months (p < 0.01). Similarly, their indexes to BSA (LAVImax and LAVImin) increased significantly, as well. Patients without a residual left-to-right interatrial shunt showed a significantly higher increase in LAVmax or LAVmin. Baseline LVEF, NT-proBNP-level or the distance covered at the 6-min walk test did not significantly change 6 weeks or 6 months after LAA closure. Conclusions LAVmax and LAVmin increase significantly after interventional LAA closure. LA enlargement does not correlate with clinical progression of heart failure. Persistent left-to-right interatrial shunt counteracts the LA enlargement. A reduced LA compliance after exclusion of the LAA from the blood circulation with consecutive increase in LA pressure may be a potential cause of LA enlargement and warrants further investigation. Trial registration German Clinical Trials Register ID: DRKS00010768 ; Registration Date 07.07.2016

Catheter navigation by intracardiac echocardiography enables zero-fluoroscopy linear lesion formation and bidirectional cavotricuspid isthmus block in patients with typical atrial flutter

Abstract Introduction One of the most helpful aspects of intracardiac echocardiography (ICE) implementation in electrophysiological studies (EPS) is the real-time visualisation of catheters and cardiac structures. In this prospective study, we investigated ICE-guided zero-fluoroscopy catheter navigation during radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL). Methods and results Thirty consecutive patients (mean age 72.9 ± 11.4 years, 23 male) with ongoing (n = 23) or recent CTI-dependent AFL underwent an EPS, solely utilizing ICE for catheter navigation. Zero-fluoroscopy EPS could be successfully accomplished in all patients. Mean EPS duration was 41.4 ± 19.9 min, and mean ablation procedure duration was 20.8 ± 17.1 min. RF ablation was applied for 6.0 ± 3.1 min (50W, irrigated RF ablation). Echocardiographic parameters, such as CTI length, prominence of the Eustachian ridge (ER), and depth of the CTI pouch on the ablation plane, were assessed to analyse their correlation with EPS- or ablation procedure duration. The CTI pouch was shallower in patients with an ablation procedure duration above the median (4.8 ± 1.1 mm vs. 6.4 ± 0.9 mm, p = 0.04), suggesting a more lateral ablation plane in these patients, where the CTI musculature is stronger. CTI length or ER prominence above the respective median did not correlate with longer EPS duration. Conclusions Zero-fluoroscopy CTI ablation guided solely by intracardiac echocardiography in patients with CTI-dependent AFL is feasible and safe. ICE visualisation may help to localise the optimal ablation plane, detect and correct poor tissue contact of the catheter tip, and recognise early potential complications during the ablation procedure. Graphical Abstrac