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Aims Catheter ablation (CA) is recommended for patients with atrial fibrillation (AF) after failure of antiarrhythmic drugs (AADs). The role of CA as ‘initial therapy’ for AF is to be determined. Methods and results Following PRISMA guideline an up-to-date pooled analysis of randomized data comparing ablation vs. AADs as first-line therapy for symptomatic AF was performed. The primary outcome was recurrence of atrial tachyarrhythmia. The secondary outcomes were improvement in quality-of-life (QoL) and major adverse events. A total of 997 patients from five randomized trials were enrolled (mean age 57.4 years, 68.6% male patients, 98% paroxysmal AF, mean follow-up 1.4 years). The baseline characteristics were similar between the ablation and AADs group. Overall pooled analysis showed that, as compared with AADs, CA as first-line therapy was associated with significantly higher freedom from arrhythmia recurrence (69% vs. 48%, odds ratio: 0.36, 95% confidence interval: 0.27–0.48, P Conclusions Catheter ablation as ‘initial therapy’ was superior to AADs in maintenance of sinus rhythm and improving QoL for patients with symptomatic paroxysmal AF, without increasing risk of serious adverse events.

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.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.In the group 1, from time-1 to time-2, a significant shortening in QTcFredericia (from 403 ± 27 to 382 ± 27 ms, p0.0001), QTcFramingham (from 402 ± 27 to 384 ± 27 ms, p0.0001), and QTcHodges (from 405 ± 26 to 388 ± 24 ms, p0.0001) 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.Our results demonstrate that CNA reduces QTc levels through neuromodulation effect whereas CP has no effect on ventricular repolarization in patients with VVS.

Background: Predictors of long‑term outcomes and an optimal catheter set for ablation of the cavotricuspid isthmus in patients with atrial flutter (AFL) are not well known. Aims: This study aimed to identify predictors of clinical events following ablation. Methods: We studied 741 patients (mean [SD] age, 62.2 [10.8] years; 248 women) who were followed for a mean (SD) time of 4.4 (2.7) years. The 2- versus 3‑electrode approach and clinical predictors ofclinical events during follow‑up were analyzed. Results: The 2‑electrode approach was faster (mean [SD] time, 62.5 [30.3] vs 101.4 [51] min; P < 0.001), associated with shorter fluoroscopy time (13.1 [9.3] vs 20.3 [12.4] min; P < 0.001), cost‑effective (8.29 [2.82] vs 11.89 [2.51] units; P < 0.001), and more effective (92.1% vs 86.1%; P = 0.012). The independent predictors of AFL recurrence were: calcium blocker use (hazard ratio [HR], 3.24; 95% CI, 1.64–6.4), mitral valve disease (HR, 1.82; 95% CI, 1.12–2.95), previous stroke and/ or TIA (HR, 2.38; 95% CI, 1.21–4.65), pulmonary artery dilatation (HR, 3.94; 95% CI, 1.22–12.73), and previous pulmonary embolism (HR, 3.77; 95% CI, 1.14–12.43); of atrial fibrillation (AF): previous AF (HR, 6.054; 95% CI, 4.58–8), left atrial enlargement (HR, 1.43; 95% CI, 1.12–1.81), number of antiarrhythmic drugs used (HR, 1.16; 95% CI, 1.05–1.28), and mitral valve disease (HR, 1.28; 95% CI, 1.04–1.58); of pacemaker implantation: tachycardia‑bradycardia syndrome (HR, 6.17; 95% CI, 3.16–12.05), previous second-/third‑degree atrioventricular block (HR, 29.4; 95% CI, 7.37–117.28), centrally acting hypotensive drugs (HR, 29.55; 95% CI, 6.14–142.25), aortic dilatation or aneurysm (HR, 2.58; 95% CI, 1.06–6.3), a labile international normalized ratio (HR, 3.45; 95% CI, 1.72–6.93), left bundle branch block (HR, 4.7; 95% CI, 1.49–14.82), the shortest R‑R interval during AFL (HR, 1.003; 95% CI, 1.001–1.005), previous cardiac surgery (HR, 2.69; 95% CI, 1.27–5.7), and aortic valve disease (HR, 2.22; 95% CI, 1.08–4.59). Conclusion: Ablation of cavotricuspid isthmus with a minimal number of electrodes is safe and effective. Specific predictors of clinical events during long‑term follow-up can be determined.

Background: Data on the feasibility of an ultrasound‑guided venous access (USGVA) for catheter ablation (CA) and electrophysiological studies (EPS) in large cohorts are scarce. The impact of the Valsalva maneuver (VM), which can increase the diameter of the femoral vein (FV), on the USGVA is unknown. Aims: The study aimed to determine the impact of the VM on FV diameters during establishing the USGVA and overall safety and effectiveness profile of the USGVA in a large cohort. Methods: Consecutive patients undergoing CA and/ or EPS with the USGVA were included, and those with anatomical landmark–guided VA were recruited as controls. In a subgroup of USGVA patients, a VM‑ ‑facilitated FV puncture was performed. The measurements obtained before and during the VM were used to calculate the estimated access area (EAA) of the FV. Results: A total of 1564 ultrasound-guided FV accesses in 876 patients and 172 FV accesses in 105 patients in the anatomical‑VA group were performed. We observed no major complications associated with the USGVA. Minor adverse events related with VA were less common in the USGVA group than in controls (1.5% vs 6.7%, respectively; P = 0.001), resulting in a 4‑fold decrease in VA‑related complications. In 204 consecutive patients who underwent the VM‑facilitated USGVA, the FV diameters increased during VM in both vertical (mean [SD], 10.1 [3] mm vs 14.4 [3.2] mm; P < 0.001) and horizontal axes (10.6 [2.9] mm vs 14.5 [3.2] mm; P < 0.001). This led to the mean (SD) increase in EAA of 38%: from 0.8 (0.2)cm2 at baseline to 1.1 (0.2) cm2 during VM (P < 0.001). Conclusions: The USGVA for EPS and/ or CA is feasible. Complication rates for the USGVA are low and result in minor events. The Valsalva maneuver is a simple way to remarkably increase the femoral vein EAA and it can be helpful in performing the USGVA in difficult cases.

Radiofrequency catheter ablation (RFCA) of premature ventricular complexes (PVC) and ventricular tachycardia (VT) can be an effective method of treatment. However, when arrhythmia originates from the left ventricular summit (LVS), an ablation performed with conventional unipolar energy sources can be challenging and may require alternative approaches. Bipolar RFCA from coronary veins and an adjacent endocardium in cases of refractory PVC/VT has not yet been studied. We retrospectively analysed cases of consecutive patients who underwent bipolar ablation in whom conventional unipolar ablation of LVS PVC/VT and antiarrhythmic drugs failed to abolish arrhythmia. Bipolar RFCA was delivered from the earliest PVC/VT activation located in the coronary venous circulation and opposite LV endocardial sites. A total number of 4 patients (1 female, age 55 ± 10 years) underwent bipolar ablation of LVS from coronary veins and an adjacent endocardium. Bipolar RFCA led to acute elimination of PVC/VT in all patients. A mean bipolar RFCA time was 244 ± 15 s. There were no complications during procedures and all antiarrhythmic drugs were discontinued. A follow-up lasted 15 ± 4 months; there was no VT recurrence and the mean 83 ± 27 % PVC burden reduction (24250 ± 1372 vs. 3000 ± 3600 PVC/d; p = 0.0228) was achieved. All patients remained symptom-free. Bipolar RFCA from coronary veins and an opposite endocardium can be used for safe and successful treatment of PVC/VT originating from a deep LV summit.

Funding Acknowledgements Type of funding sources: None. Introduction Ablation for atrial fibrillation (AF) carries a significant risk of esophageal injury. Current methods of esophageal protection are invasive, expensive and their cost-effectiveness can be questioned. Standard placement of dispersive patch (DP) at patient’s back exposes esophagus to radio-frequency (RF) current-mediated thermal injury and such complications as esophageal wall ulceration, peri-esophageal injury or life-threatening atrio-esophageal fistula. Redirecting RF current by DP repositioning to anterior chest can theoretically protect oesophagus from thermal injury, however, such an approach has not yet been investigated. Aim To determine feasibility of anterior DP position for treatment of AF using RF catheter ablation (RFCA)-based system. Methods We retrospectively analysed consecutive patients undergoing RFCA-based pulmonary vein isolation (PVI) using multi-electrode PVAC catheter with DP located either in anterior or traditional-posterior position. Two additional patients underwent point-by-point RFCA and mapping of PV ostia with impedance measurements during RFCA performed using anterior and posterior DP positioning. Results 62 patients (25 females, age 60 ± 12 years) underwent PVI using PVAC: 40 patients in posterior and 22 in anterior DP group. There were no major complications during procedures. There was no significant difference in AF recurrence rate between anterior and posterior DP groups during one-year follow up (log rank p = 0.065). In two additional consecutive patients (1 female, age 74 ± 2 years) undergoing point-by-point RFCA a total number of 30 measurements around PV ostia were performed. There was a significant difference between impedance values in anterior vs posterior DP positions (134 ± 7 Ω vs 122 ± 8 Ω, p = 0.0004). Conclusions Anterior position of dispersive electrode for PV isolation using RFCA-based systems is safe, feasible, atraumatic and is not associated with any additional cost. Apart from redirecting RF current away from the esophagus, anterior dispersive patch placement is associated with higher impedance values which can act as an additional protection. Possible prevention of esophageal complications using anterior dispersive patch positioning needs to be determined in prospective studies. Abstract Figure. AF-free survival and impedance

Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is a cornerstone for catheter ablation (CA) of atrial fibrillation (AF), however, long-term efficacy of PVI is frequently below expectations. PVI is invasive, expensive and may be associated with devastating complications. It has been postulated that vagally-mediated AF can be treated by attenuation of parasympathetic drive to the heart using cardioneuroablation by means of radiofrequency CA (RFCA) of the right anterior ganglionated plexus (RAGP), however, data in literature and guidelines are lacking. Purpose To examine the efficacy of RFCA targeting RAGP without PVI in management of vagal AF. Methods We included consecutive 9 male patients with vagal AF who underwent RFCA of RAGP without PVI. RAGP was targeted anatomically from the right atrium (RA) at the postero-septal area below superior vena cava (SVC) and from the left atrium (LA) if needed. The aim was to achieve >30% increase in heart rate (HR) . The follow up consisted of regular visits and Holter ECG conducted every 3 months. Results A total number of 9 patients (age 52 ± 13) with vagally-mediated AF underwent RFCA of RAGP (mean RAGP RF time 147 ± 85, max power 34 ± 8W). The mean procedure time was 60 ± 29min. HR increase >30% was achieved in 8 (89%) patients (pre-RF vs post-RF: 58 ± 8bpm vs 87 ± 12bpm, p = 0.00002) . Transseptal to reach RAGP also from the LA was needed in 2 (22%) patients. There were no major complications during the procedures. The follow up lasted 6 ± 2 months. Antiarrhythmic drugs were discontinued in 8 (89%) patients. There was 1 (11%) AF recurrence in the patient in whom targeted HR acceleration during RFCA was not achieved. B-blockers were administered in 6 (67%) patients due to increased HR and such treatment was well tolerated by all. Conclusions Catheter ablation of RAGP without performing PVI is feasible and can be effective in majority of patients with vagally-mediated AF. Increased HR after such cardioneuroablation can be well controlled using b-blockers and is usually associated with mild symptoms. The role of cardioneuroablation for treatment of vagally-mediated AF needs to be determined in prospective trials. Abstract Figure. Cardioneuroablation in vagal AF

Introduction Biophysics of bipolar radiofrequency catheter ablation (Bi-RFCA) suggest more condensed and selective lesion formation when compared to conventional-unipolar approach. Whether more selective Bi-RFCA can result in safe and effective ablation of arrhythmic substrates in close proximity of His bundle has not been investigated so far. Purpose To determine feasibility and effectiveness of Bi-RFCA in His bundle area. Methods Consecutive patients after failed unipolar ablation for symptomatic premature ventricular complexes (PVC) or ventricular tachycardia (VT) originating from the vincity of His bundle underwent Bi-RFCA. Results We ultimately enrolled 8 patients (2 females, age 60 ± 15 years) to undergo Bi-RFCA of PVC/VT. Previous pharmacological treatment consisting of at least one antiarrhythmic drug and conventional catheter ablation failed in all. Bi-RFCA using open-irrigated and non-irrigated ablation catheters (AC) was delivered from two earliest PVC/VT activation sites located in the vincity of His bundle (Figure, panels A-B). A total number of 93 bipolar applications were delivered (mean bipolar RF time 508 ± 565s, mean power 35 ± 13W, mean impedance 163 ± 18Ω). Transient conduction disturbances occurred in 2 patients and were associated with mechanical compression of conduction system. No persistent conduction disturbances occurred. Bipolar RFCA led to acute elimination of PVC/VT in 6 (75%) patients. Follow up lasted 11 ± 5 months: two patients underwent repeat procedure using dual-irrigated Bi-RFCA, there was no VT recurrence and 72% PVC burden reduction was achieved (16200 ± 11600 pre-ablation vs 4500 ± 6200 post-ablation PVC/day, p = 0,035) (Figure, panel C). Conclusion Bi-RFCA performed in proximity of His bundle can be safe and effective in majority of patients. Abstract Figure. Bipolar ablation of parahisian PVC/VT

Background Data on occurrence, management and outcomes of iatrogenic aortic dissections (IAD) as a complication of catheter ablation (CA) do not exist. Purpose To evaluate multicenter data on occurrence, management and outcomes of IAD as a complication of CA. Methods Data on occurrence, management and outcomes of documented vascular dissections from 10 centers were evaluated. Results IADs occurred in 7 patients (2 females, age 63 ± 8 years). Indications for CA were frequent premature ventricular complexes (PVC)/ventricular tachycardia (VT) in 6 patients (86%) and left-sided accessory pathway in the remaining one (14%). Hypertension was most frequent comorbidity (4 pts, 57%). All IADs occurred during retrograde advancement of ablation catheter. In the vast majority of patients creation of IAD during catheter advancement was not associated with any symptoms (6 pts, 86%). IAD was initially detected using trans-luminal angiogram in 5 (71%) and further confirmed using computed tomography (CT) (5 pts, 71%), conventional angiography (2 pts, 28%) and ultrasound (2 pts, 28%). One IAD was detected during CT scan performed for other indication after CA. There was one IAD-related death and IAD was evaluated post-mortem. Follow-up lasted 10 ± 19 months. Four patients were treated conservatively, one patient underwent descending aorta stenting and one femoral artery stenting. Conclusions IAD during CA is a rare but can be devastating. Early recognition can be difficult. Conservative management of IAD is an option of treatment.

Respiratory cycle-dependent atrial tachycardia (RCAT) is rare. RCAT can be associated with severe symptoms and trigger atrial fibrillation. Focal radiofrequency ablation of RCAT can be a successful method of treatment. In the presented case RCAT originated from the roof of the left atrium - the site not previously reported in the literature. Ablation led to complete elimination of arrhythmia with no recurrence during follow up.

INTRODUCTION Radiofrequency (RF) catheter ablation (RFCA) of ventricular tachycardia (VT) is an effective method of treatment. However, when arrhythmia has ischemic etiology and originates from the posterosuperior process (PSP) of the left ventricular (LV) base, ablation performed with conventional unipolar energy sources may be challenging or impossible. METHOD AND RESULT A 67-year-old male after six unsuccessful RFCA for highly symptomatic VT originating from PSP of LV base underwent successful RFCA using multiple bipolar RF applications delivered between two electrodes located at LV endocardium and adjacent right atrial sites. CONCLUSION This case report shows that bipolar RFCA can be used for safe and successful treatment of VT originating from deep PSP of LV base.

When arrhythmia originates from the His bundle (HB) area conventional radiofrequency catheter ablation (RFCA) is associated with increased risk of atrioventricular block (AVB). Biophysics of bipola...

Intramural origin of ventricular arrhythmias is one of the reasons for failure of catheter ablation, especially in nonischemic substrates. Conventional unipolar ablation has limited efficacy for the creation of deep transmural lesions in the ventricular myocardium, and alternative ablation strategies have been developed to overcome this problem. These novel approaches include simultaneous unipolar ablation, bipolar ablation, use of low-ionic irrigant solution, needle ablation, and ethanol ablation. This review provides an overview of each one of these techniques, including their main advantages and limitations.

Background Catheter ablation has been considered an effective strategy for the treatment of ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS). However, the inherent complexity of the anatomy of the LVS may result in failed ablation or recurrence of VA. Objective The purpose of this multicenter study was investigate the procedural outcomes of ablation of LVS VA. Methods A total of 238 patients (54.6% men; mean age 53.2 ± 15.0 years) undergoing catheter ablation of LVS VA were included. Baseline characteristics, procedural parameters, and clinical outcomes were analyzed. Results Acute procedural success was achieved in 199 patients (83.6%). Initial epicardial ablation via the coronary venous system (93.8% [91/97]) or percutaneous transpericardial approach (6.2% [6/97]) achieved successful ablation in 40 of 97 patients (41.2%), and VA was eliminated by initial approaches from the aortic sinus of Valsalva or subvalvular endocardium in 68 of 139 patients (48.9%; P = .29). Multisite ablations were performed in the process of acute VA elimination in 105 patients (51.8%), and 7 complications occurred. During median follow-up of 26 (1–87) months, 82.2% of patients with acute success were free from VA recurrences, and the overall long-term success rate was 68.1%. Multisite ablation was the only independent predictor of VA recurrences. Conclusion Acute elimination of VA originating from the LVS could be achieved in 83.6% of patients, with 82.2% having no VA recurrences. Despite acute elimination of VA with multisite ablation, the incidence of VA recurrence still was high.

INTRODUCTION Bipolar radiofrequency catheter ablation (Bi-RFCA) emerged as an option for treatment of arrhythmias resistant to the conventional approach. Data on safety issues of Bi-RFCA, including temperature values of intracardiac return electrode (IRE) are lacking. OBJECTIVE To determine the safety profile of Bi-RFCA regarding temperature measurements obtained from nonirrigated IRE of different sizes. METHODS The study group consisted of consecutive patients after failed conventional RFCA who underwent Bi-RFCA. RESULTS Out of 1510 RFCA performed in our center, 19 patients underwent Bi-RFCA due to refractory to previous RFCA ventricular arrhythmias (15 patients) or typical atrial flutter (four patients). Nonirrigated small (4 mm) and large (8 mm) tip catheters were used as IRE in 14 (including three cross-overs to 8 mm IRE) and five patients, respectively. A total number of 164 bipolar applications were performed (128 for 4 mm and 36 for 8 mm IRE). Maximal temperatures of 4 mm IRE were significantly higher than those of 8 mm IRE (63°C ± 16°C vs 43°C ± 4°C; P = .027). A significant rise of temperature and steam-pops, preventing further Bi-RFCA, occurred in seven patients treated with 4 mm IRE. Bi-RFCA using 4 mm IRE operated at significantly higher impedance values (211 ± 83 vs 143 ± 38; P = .04) and lower power values (mean 20 W ± 6 W vs 32 W ± 7 W, P = .0005; max 29 W ± 9 W vs 39 W ± 10 W, P = .027). CONCLUSION The use of 8 mm IRE for Bi-RFCA is associated with lower temperatures of the catheter used as ground and lower incidence of steam-pops which may suggest a better safety profile than 4 mm IRE. Determination of safety/efficacy balance requires further studies.

Background Implantable cardioverter defibrillator (ICD) offers an opportunity to examine vulnerability to ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict VT/VF recurrences has not yet been established. Purpose To examine the predictive value of NIPS for identification of patients with VT/VF recurrences. Methods The study group consisted of consecutive 105 ICD recipients included in the prospective NIPS-ICD study (ClinicalTrials ID: NCT02373306) (88 males, age 65 ± 11 years). The patients underwent NIPS using the protocol up to three premature extrastimuli at 600-500- and 400-ms drive cycle lengths. The endpoint of NIPS was induction of sustained VT or VF or completion of the protocol. Results VT/VF was induced in 29 (27.6%) patients. During a 12-month follow-up NIPS-inducible patients had significantly more frequently appropriate ICD therapy than noninducible patients (17% vs 4%, P = 0.023). NIPS-induced VT/VF had a sensitivity of 63%, specificity of 75%, positive predictive value of 17%, and negative predictive value of 96% for identification of patients with future VT/VF. Apart from NIPS, age ≥ 65 years, QRS duration, treatment with angiotensin-converting enzyme, history of coronary artery bypass grafting, history of VT/VF prior to NIPS, and prior appropriate ICD therapy were also associated with VT/VF recurrences. Multivariate analysis showed that, together with QRS duration, NIPS result was an independent predictor of future VT/VF. Predictive value of NIPS was significantly higher in ischemic than nonischemic patients. Conclusions NIPS result is associated with future VT/VF. Noninducibility at NIPS identifies those patients with high accuracy who will have uneventful follow-up.

Background and aim: To assess safety and efficacy of antazoline for termination of atrial fibrillation (AF) occurring during ablation of accessory pathways (AP). Methods: We analyzed electrophysiological mechanism of antazoline (changes in A-A interval) and the percentage of pre-excited QRS complexes before and after antazoline administration. The total dose administered and the time from the start of injection to sinus rhythm restoration were also measured. Results: Out of consecutive 290 patients with Wolff-Parkinson-White syndrome undergoing radiofrequency (RF) ablation, 12 (4.1%) (4 females, mean age 36 ± 20 years) developed sustained AF which did not stop spontaneously within 10 min, and antazoline in 100 mg repeated boluses was administered. In all 12 patients the drug restored sinus rhythm after a mean of 425 ± 365 s (range 43–1245 s) using a mean cumulative dose of 176 ± 114 mg (range 25–400 mg). The drug slightly prolonged R-R intervals during AF (from 383 ± 106 to 410 ± 70 ms) and reduced the percentage of fully pre-excited QRS complexes (from 35% to 26%). Intracardiac recordings showed gradual increase in A-A intervals, as well as regularization and decreasing fractionation of atrial activity following drug injection (mean A-A interval of 162 ± 30 ms at baseline vs. 226 ± 26 ms shortly before sinus rhythm restoration, p < 0.001). AP was not completely blocked in any patient which enabled continuation of ablation. Conclusions: Antazoline safely and rapidly converts AF into sinus rhythm during ablation of AP. The drug does not block AP completely, enabling continuation of ablation. The drug converting AF into more organized atrial activity (atrial flutter/tachycardia) before sinus rhythm resumption.

Background The use of an implantable cardioverter defibrillator (ICD) is a widely used and effective therapy, which reduces the risk of cardiac death in many cardiac diseases, both implanted for secondary and primary prevention. However, recurrent arrhythmias and ICD discharges have adverse prognostic significance. Additional parameters that would identify patients who are at increased risk of arrhythmias and appropriate ICD interventions would be of clinical value. Modern ICDs are relatively complex devices with a number of functions, including the possibility to perform noninvasive programmed stimulation (NIPS) with an implanted electrode located in the right ventricle. Methods/Design The aim of the study is to evaluate the usefulness of NIPS in determining the likelihood of life-threatening arrhythmic events in patients with ICD. The study will include 150 consecutive patients with an ICD implanted both for primary and secondary prevention, regardless of etiology, who are followed in the outpatient clinic of our center and do not meet the exclusion criteria. A 12-step St. George’s Hospital NIPS protocol using ICD will be performed. The endpoint is to induce sustained ventricular arrhythmia (VT lasting more than 30 seconds or hemodynamically unstable VT/VF) or the end of the protocol. In case of serious and/or hemodynamically unstable heart rhythm disorders resistant to treatment with a low-energy antiarrhythmic pacing (ATP), the patient receives a short-term intravenous general anesthesia, and internal or external defibrillation is performed. Outpatient follow-up will be conducted during the pre-scheduled ICD control visits. An analysis of records of a registered memory device will be collected, a patient will be interviewed, and physical examination will be carried out. The follow-ups will be held every 3 months for 1 year. The primary endpoint of the follow-up will be appropriate intervention of ICD or sudden cardiac (arrhythmic) death; the secondary, appropriate ICD intervention, or death from cardiovascular causes; and the tertiary, appropriate ICD intervention, death or hospitalization for cardiovascular causes. Discussion It is expected that appropriate ICD interventions during follow-up will occur more often in patients who had sustained ventricular arrhythmias induced during NIPS. Clinical trials registry ClinicalTrials.gov, NCT02373306, date of registration: 26 February 2015.