Sample entropy (SampEn) was reported to be useful in the assessment of the complexity of heart rate dynamics. Permutation entropy (PermEn) is a new measure based on the concept of order and was previously shown to be accurate for short, non-stationary datasets. The aim of the present study is to assess if SampEn and PermEn obtained from baseline recordings might differentiate patients with various outcomes of the head-up tilt test (HUTT). Time-domain heart rate variability (HRV) indices and several nonlinear parameters were calculated using 500 RR interval-long ECG recordings done before tilting in patients with a history suggesting vasovagal syncope. Groups of patients with so-called cardiodepressive vasovagal syncope (VVS_2) during HUTT and patients who did not faint during the test were compared. Two types of HUT tests were analyzed: with spontaneous (SB) or controlled breathing (CB). In our study, SampEn was higher in VVS_2 patients during SB, and PermEn was higher in VVS_2 patients during CB. Irrespective of the type of breathing during the test, SampEn and PermEn were similar in patients with the same type of reaction during HUTT. The use of several entropy-based parameters seems to be useful in HRV assessment in patients with vasovagal fainting.

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Rhythm control strategy for AF is limited by drug toxicity and side effects, and recent trials have shown that this strategy is not superior to a rate control one. New antiarrhythmic drugs, free of undesired effects, would enhance rhythm control, with the possibility of sinus rhythm restoration and maintenance. A promising find in the search for new antiarrhythmic therapies is atrial-tissue specific ion channels. The findings that the ultrarapid delayed rectifier (I_Kur) and the inwardly rectifying, acetylcholine-regulated current (I_K-Ach) exist in atrial but not ventricular tissue increase the probability that atrioselective drugs without ventricular proarrhythmic toxicity can be developed for treatment of patients with AF. There are also other potential targets for atrial-selective therapy: transient outward current (I_to), rapidly and slowly activating delayed rectifier currents (I_Kr and I_Ks), atrial sodium current (I_Na) and atrially expressed connexins. New drugs under development with promising atrial-selectivity include: tertiapin, NIP-142, NIP-141, JTV-519, AVE0118, AVE1231, DPO-1, AZD7009 and many others. Among such new agents, vernakalant hydrochloride is currently in an advanced phase of development and has already been evaluated in clinical trials. In this overview, we describe the history and current state of developmental process of the drug, as well as its mechanism of action and influence on electrophysiological parameters. Vernakalant seems to be effective in terminating recent-onset AF, but is not efficacious in long-lasting AF and atrial flutter. The drug may be relatively free of proarrhythmic effects, and exerts a protective effect on ventricular tissue and ventricular repolarization. It is expected that the intravenous formulation will soon be approved for the pharmacological termination of recent-onset AF.

Background: The use of subcutaneous implantable cardioverter-defibrillators (S-ICD) has been growing in Poland since 2014. The Polish Registry of S-ICD Implantations was run by the Heart Rhythm Section of the Polish Cardiac Society between May 2020 and September 2022 to monitor the implementation of that therapy in Poland.Aims: To investigate and present the state-of-the-art of S-ICD implantation in Poland. Methods: Implanting centers reported clinical data of patients undergoing S-ICD implantations and replacements, including age, sex, height, weight, underlying disease, history of pacemaker and defibrillator implantations, indications for S-ICD, electrocardiographical parameters, procedural techniques, and complications.Results: Four hundred and forty patients undergoing S-ICD implantation (411) or replacement (29) were reported by 16 centers. Most patients were in New York Heart Association class II (218 patients, 53%) or I (150 patients, 36.5%). Left ventricular ejection fraction was 10%-80%, median (IQR) was 33% (25%-55%). Primary prevention indications were present in 273 patients (66.4%). Non-ischemic cardiomyopathy was reported in 194 patients (47.2%). The main reason for the choice of S-ICD were: young age (309, 75.2%), risk of infectious complications (46, 11.2%), prior infective endocarditis (36, 8.8%), hemodialysis (23, 5.6%), and immunosuppressive therapy (7, 1.7%). Electrocardiographic screening was performed in 90% of patients. The rate of adverse events was low (1.7%). No surgical complications were observed.Conclusions: Qualification for S-ICD in Poland was slightly different when compared to the rest of Europe. The implantation technique was mostly consistent with the current guidelines. S-ICD implantation was safe, and the complication rate was low.

Progressive aging of the population and the increasing number of complications of electrotherapy procedures are the main reasons of a remarkable increase in the number of transvenous extraction procedures of pacemaker (PM) and implantable cardioverter-defibrillator (ICD) leads in the elderly patients. To assess the safety and effectiveness of such procedures in patients under or over 80 years of age. The study included all patients who underwent transvenous PM/ICD lead extraction in 2003-2011. All patients were divided into two groups based on their age at the time of the procedure: group A included patients under 80 years of age (134 patients; 97 male, 37 female) and group B included patients over 80 years of age (26 patients; 16 male, 10 female). No differences were found between the two groups in terms of gender proportions, comorbidities, New York Heart Association (NYHA) functional class, and left ventricular ejection fraction. In total, 220 leads were removed (group A: 63 defibrillating and 122 pacing leads, group B: 2 defibrillating and 33 pacing leads). The most common indication for the lead removal procedure in both groups was infection, either in the form of PM/ICD pocket infection (46 and 13 cases, respectively) or infective endocarditis (18 and 2 cases, respectively). Procedural outcomes in both groups were not statistically different in terms of the final outcome or complication rates. The results in groups A and B were as follows: complete success 95.5% vs. 96.2%, respectively, clinical success 3% vs. 3.8%, respectively, and failure 1.5% vs. 0%, respectively, with no significant differences between the groups. No major complications of the procedure were observed in either of the groups. Our findings indicate that transvenous extraction of PM/ICD leads appears to be a safe and effective procedure both in relatively younger patients and in patients over 80 years of age.

Introduction: Syncope is defined as transient loss of consciousness, due to decrease in brain perfusion. The most frequent mechanism is vasovagal syncope. In many patients, the cause of syncope remains unspecified, despite an extensive diagnostic work-up. Tilt-test (TT) is an acknowledged diagnostic tool for syncope. Currently, the so-called Italian protocol of TT is most widely used. Vasovagal syncope is caused by impaired circulatory regulation in response to orthostatic stress. One of the available tools to examine the influence of the nervous system on the circulation is the analysis of heart rate variability (HRV). Despite numerous publications concerning HRV parameters and autonomic regulation in patients with syncope, direct comparisons and metaanalysis of the results is impossible, due to variability of TT protocols and study group specifications. Aim of the study: As there is no uniform model of HRV during TT, we aimed to analyze HRV parameters during TT (performed according to the Italian protocol) in patients with vasovagal syncope, in order to determine the possible application of HRV measurements in clinical practice in that group of patients. Detailed objectives were: (1) analysis and comparison of HRV in patients with and without the history of syncope; (2) analysis of HRV changes in consecutive stages of TT; (3) identification of possible HRV differences between patients with positive and negative TT results. Material and methods: Patients between 18 and 50 years of age were qualified for the study, if they had a history of at least 2 incidents of syncope or presyncope within the preceeding 6 months, and if signs and symptoms indicated the vasovagal mechanism. The study group included 150 patients: 100 consecutive patients with a postive TT result (POS), and 50 consecutive patients with a negative TT result (NEG). The control group (CG) comprised 50 volunteers with no history of syncope nor presyncope, matched according to age and sex to the study group. In all patients a TT was performed according to the Italian protocol, with paced breathing at a rate of 15/min. Time-domain (meanRR, SDNN, RMSSD, pNN50) and frequency-domain (abs_LF, abs_HF, rel_LF, rel_HF, norm_LF, norm_HF, LF/HF) HRV parameters were analyzed and compared at different stages of TT in the study groups as specified above. Results: 100 patients at the age of 18-44 years were included in the POS group, 50 patients at the age of 18-39 years in the NEG group, and 50 volunteers at the age of 20-39 in the CG. Volunteers in the control group developed unexpectedly high percentage of positive TT (14 patients). For consistency of analysis, the CG was thus subdivided according to the result of the TT into CG_POS (positive result of TT) – 14 patients, and CG_ NEG (negative result of TT) – 36 patients. Based on HRV analaysis, no significant differences in HRV values were noted between patients with a history of syncope and positive or negative result of TT. Upright tilt resulted in HRV changes of the same direction and value in syncopal patients in the POS and NEG goup, as well as in patients in the CG_NEG group. Conclusion: HRV values and changes of those values at subsequent stages of TT were not different between syncopal patients with postive or negative TT result, or negative TT control group. The Italian protocol of TT may be associated with a surprisingly high percentage of false positive results.

Background: Sense‐B‐noise is a newly reported possible cause of inappropriate shocks in patients with subcutaneous implantable cardioverter‐defibrillators (S‐ICDs). The nature of that noise is unknown, it is not related to mechanical failure of the S‐ICD system. Reprogramming to the secondary sensing vector is suggested by the producer as a possible solution.Methods: We analyzed the medical records of S‐ICD recipients from two university clinical centers (Gdansk and Szczecin, Poland). Our aim was to determine the rate of sense‐B‐noise, and whether the secondary sensing vector would be available for reprogramming if such a problem occurred in our patients.Results: The sense‐B‐noise issue affected three patients in our cohort (3%), which corresponds to the incidence of 0.012 events per patient‐year of follow‐up. The primary vector was permanently used in 47 patients (52%), secondary in 28 (31%), and alternate in 16 (17%), respectively. Therefore, the total number of patients potentially vulnerable to sense‐B noise (with the primary or alternate vector programmed permanently) was 63 (69%). Among those 63 patients, 51 individuals (81%) had also the secondary vector available for permanent use.Conclusion: The sense‐B‐noise affected 3% of patients in our cohort, with an incidence of 0.012 per patient‐year of follow‐up. Most patients potentially vulnerable to sense‐B noise could be reprogrammed to the secondary sensing vector, if necessary. Further investigation of the sense‐B‐noise issue is needed.