Szymon Budrejko

Lone Atrial Fibrillation - What Do We Know?

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Despite the common association of AF with cardiovascular disease, some patients can be classified as ‘lone AF’. The latter is essentially a diagnosis of exclusion, and should be preceded by careful evaluation, including thorough collection of medical history, physical examination, blood pressure measurement, laboratory tests, ECG, echocardiography and, possibly, chest x-ray and exercise testing. Lone AF patients were initially thought to have a good prognosis with respect to thromboembolism and mortality, compared with the general AF population, but more recent data suggest otherwise. This review focuses on the clinical epidemiology and management aspects of lone AF, as well as various associated novel risk factors, such as familial, genetic and socioeconomic factors, alcohol, sports activity and biochemical markers.

Vernakalant hydrochloride for the treatment of atrial fibrillation

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 (IKur) and the inwardly rectifying, acetylcholine-regulated current (IK-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 (Ito), rapidly and slowly activating delayed rectifier currents (IKr and IKs), atrial sodium current (INa) 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.

Dronedarone: An overview

Abstract Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Until recently, a rhythm control strategy for AF has been limited by drug toxicity and side-effects, and landmark AF trials have shown that such a strategy is not superior to a rate control one. New antiarrhythmic drugs, free of undesired effects, would enhance the rhythm control strategy, with the possibility of sinus rhythm restoration and maintenance. One of the promising drugs recently approved for clinical use is dronedarone. This drug has amiodarone-like antiarrhythmic and electrophysiological properties, despite it having a modified structure and lacking an iodine moiety. Thus, dronedarone lacks amiodarones organ toxicity (including adverse thyroid and pulmonary effects). The efficacy of dronedarone has been investigated in several clinical trials, proving its effect in the prevention of AF recurrence, rate control in paroxysmal/persistent and permanent AF, reduction of cardiovascular hospitalization or death from any cause, and others. Indirect comparisons with amiodarone, as well as one head-to-head study of the two drugs, indicate that the relative safety of dronedarone may be at a cost of its lower antiarrhythmic efficacy compared with amiodarone.

Entropy Measures in the Assessment of Heart Rate Variability in Patients with Cardiodepressive Vasovagal Syncope

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.

Safety and effectiveness of transvenous extraction of pacemaker and implantable cardioverter-defibrillator leads in patients under or over 80 years of age.

BACKGROUND 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. AIM 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. METHODS 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). RESULTS 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. CONCLUSIONS 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.

Electrophysiological features in patients with sinus node dysfunction and vasovagal syncope

Introduction Syncope is a common presentation of sinus node dysfunction (SND). Some patients who receive a permanent pacemaker due to SND do not benefit from it and further diagnostic workup leads to the diagnosis of vasovagal syncope (VVS). The aim of the study was to identify electrophysiological criteria that can be used for identification of patients with SND and concurrent VVS. Material and methods Transoesophageal atrial pacing (TAP) was performed in 100 patients divided into four groups depending on symptoms and TAP results. Standard electrophysiological parameters of sinus node function and their variability were obtained in the basal state and after pharmacological autonomic blockade (AB). Results Patients with concurrent SND and VVS had a greater variability of sinoatrial conduction time assessed by Strauss’ method than patients without incidents of syncope (83.2 ±53.9 vs. 34.1 ±19.6, 47.8 ±33.6 and 32.1 ±22.99). Apart from abnormal sinus node recovery time and second pause, patients with SND had bigger basal state variability of these parameters. In patients with SND and concurrent vasovagal syncope the variability of sinus node recovery time (SNRT), corrected SNRT (cSNRT) and second pause (IIP) decreased after autonomic blockade. Conclusions Patients with concurrent SND and VVS have distinct electrophysiological features – greater sinoatrial conduction time (SACT) variability and the decrease of SNRT, cSNRT and IIP variability after AB. However, further studies in larger study groups are needed to validate our findings. Transoesophageal atrial pacing is a useful procedure in patients with syncope, especially when the coexistence of more than one cardiac cause is suspected.

Anticoagulant Prevention in Patients with Atrial Fibrillation: Alternatives to Vitamin K Antagonists

Patients with nonvalvular atrial fibrillation (AF) and risk factors for stroke need anticoagulation to avoid thromboembolic complications. Vitamin K antagonists (VKAs) are an established pharmacological group the use of which is recommended by guidelines. However, VKAs (like warfarin) have major disadvantages, such as a variable dose-effect relationship, drug and food interactions, the need for regular blood testing and dose titration, and, finally, a substantial risk of bleeding. New oral anticoagulants are intended to replace warfarin, being at least as safe and effective, and lacking some of the disadvantages of VKAs. Clinical data for dabigatran, rivaroxaban, apixaban and edoxaban, and other new drugs, are discussed in this article with special focus on their use in nonvalvular AF.

Generalised heart rate statistics reveal neurally mediated homeostasis transients

Distributions of accelerations and decelerations, obtained from increments of heart rate recorded during a head-up tilt table (HUTT) test provide short-term characterization of the complex cardiovascular response to a rapid controlled dysregulation of homeostasis. A generalised statistic is proposed for evaluating the neural reflexes responsible for restoring the homeostatic dynamics. An evaluation of the effects on heart rate of the neural regulation involved in achieving homeostasis indicates a distinction between vasovagal patients and healthy subjects who are not susceptible to spontaneous fainting. A healthy cardiovascular response to the HUTT test is identified in the sympathetic tone appropriately punctuated by vagal activity.

One-Year Follow-Up of Patients Undergoing Transvenous Extraction of Pacemaker and Defibrillator Leads

Introduction The number of pacemaker and ICD implantations has increased substantially in the recent years. Therefore, complications are also observed in a greater number. In many cases, transvenous extraction of the previously implanted device (pacemaker or ICD) is the only solution. One may find in the literature information about the efficacy and safety of that procedure, but data concerning the results of long-term follow up are still limited. Aim The aim of the study was to assess the one-year mortality in the cohort of patients undergoing transvenous lead extraction procedures in our centre. Methods Records of the patients undergoing transvenous lead removal in the Department of Cardiology and Electrotherapy of the Medical University of Gdańsk were analyzed. We collected detailed information about 192 patients that had undergone the procedure from January 2003 until June 2012. Data were collected from medical and surgical records. We analyzed concomitant diseases, indications, and possible complications. Long-term follow-up data were gathered in the follow-up ambulatory records and over-the-phone interviews with patients or families. In several cases, we consulted the database of the Polish National Health Fund. Results During the early post-operative period 5 patients died, although none of those deaths was associated with the procedure itself. No other major complications were observed. During one-year follow-up other 5 patients died, which gave the overall one-year survival rate of 92.7%. Heart failure, renal failure and an infective indication showed significant association with increased mortality. Conclusion Results of transvenous lead extraction, a relatively safe procedure, should be assessed over time extending beyond the sole perioperative period. Some complications may be delayed in their nature, and may be observed only during the long-term follow up.

Implantation of additional subcutaneous array electrode reduces defibrillation threshold in ICD patients - preliminary results.

Introduction Among the recipients of implantable cardioverter-defibrillators (ICDs), there is a group of patients in whom the defibrillation threshold (DFT) is too high to enable a sufficient safety margin between the DFT and the maximal available output of the device. The aim of the study was to investigate the ability of an additionally implanted single-coil subcutaneous array electrode to reduce the DFT in such patients. Material and methods Medtronic 6996SQ electrode was implanted in 15 patients selected from our follow-up group of 741 ICD patients: 10 of them had insufficient post-implant DFT safety margin, and 5 had ineffective first maximal energy shock as recorded by the device. In 6 cases the patients had CRT-D devices, in 5 cases – dual-chamber ICDs, and in 4 cases – single-chamber ICDs. In all patients but one the defibrillating electrode was single-coil. In one patient it was dual-coil. The underlying disease was coronary artery disease in 10 patients, dilated cardiomyopathy in 4 patients and hypertrophic cardiomyopathy in 1 patient. Results The subcutaneous electrode was successfully implanted in all the patients qualified for the procedure. No technical issues or perioperative complications were observed. Mean DFT was reduced from 33.3 ±4.1 J before the procedure to 25.3 ±4.4 J after the implantation procedure (p < 0.01). Conclusions Our results show that the use of a single-coil subcutaneous electrode to reduce the DFT is a safe and effective procedure. Further studies are necessary to confirm these results.