Arrhythmic risk stratification in ischemic, non-ischemic and hypertrophic cardiomyopathy: A two-step multifactorial, electrophysiology study inclusive approach.

Annual arrhythmic sudden cardiac death ranges from 0.6% to 4% in ischemic cardiomyopathy (ICM), 1% to 2% in non-ischemic cardiomyopathy (NICM), and 1% in hypertrophic cardiomyopathy (HCM). Towards a more effective arrhythmic risk stratification (ARS) we hereby present a two-step ARS with the usage of seven non-invasive risk factors: Late potentials presence (≥ 2/3 positive criteria), premature ventricular contractions (≥ 30/h), non-sustained ventricular tachycardia (≥ 1episode/24 h), abnormal heart rate turbulence (onset ≥ 0% and slope ≤ 2.5 ms) and reduced deceleration capacity (≤ 4.5 ms), abnormal T wave alternans (≥ 65µV), decreased heart rate variability (SDNN < 70ms), and prolonged QTc interval (> 440 ms in males and > 450 ms in females) which reflect the arrhythmogenic mechanisms for the selection of the intermediate arrhythmic risk patients in the first step. In the second step, these intermediate-risk patients undergo a programmed ventricular stimulation (PVS) for the detection of inducible, truly high-risk ICM and NICM patients, who will benefit from an implantable cardioverter defibrillator. For HCM patients, we also suggest the incorporation of the PVS either for the low HCM Risk-score patients or for the patients with one traditional risk factor in order to improve the inadequate sensitivity of the former and the low specificity of the latter.

Permanent pacemaker implantation in unexplained syncope patients with electrophysiology study-proven atrioventricular node disease.

OBJECTIVE: Syncope, whose cause is unknown after an initial assessment, has an uncertain prognosis. It is critical to identify patients at the highest risk who may require a pacemaker and to identify the cause of recurrent syncope to prescribe proper therapy. The aim of this study was to evaluate the effect of permanent pacing on the incidence of syncope in patients with unexplained syncope and electrophysiology study (EPS)-proven atrioventricular (AV) node disease. METHODS: This was an observational study based on a prospective registry of 236 consecutive patients (60.20 ± 18.66 years, 63.1% male, 60.04 ± 9.50 bpm) presenting with recurrent unexplained syncope attacks admitted to our hospital for invasive EPS. The decision to implant a permanent pacemaker was made in all cases by the attending physicians according to the results of the EPS. A total of 135 patients received the antibradycardia pacemaker (ABP), while 101 patients were declined. RESULTS: The mean of reported syncope episodes was 1.97 ± 1.10 (or presyncope 2.17 ± 1.50) before they were referred for a combined EP-guided diagnostic and therapeutic approach. Over a mean follow-up of approximately 4 years (49.19 ± 29.58 months), the primary outcome event (syncope) occurred in 31 of 236 patients (13.1%), and 6 of 135 (4.4%) patients in the ABP group as compared to 25 of 101 (24.8%) in the no pacemaker group (p < 0.001). CONCLUSION: Among patients with a history of unexplained syncope, a set of positivity criteria for the presence of EPS-defined AV node disease identifies a subset of patients who will benefit from permanent pacing.

Leadless Cardiac Pacemakers: Current status of a modern approach in pacing.

Since the first transvenous pacemaker implantation, which took place 50 years ago, important progress has been achieved in pacing technology. Consequently, at present, more than 700,000 pacemakers are implanted annually worldwide. However, conventional pacemakers' implantation has a non-negligible risk of periprocedural and long-term complications associated with the transvenous leads and pacemaker pocket. Recently, leadless pacing systems have emerged as a therapeutic alternative to conventional pacing systems that provide therapy for patients with bradyarrhythmias, while eliminating potential transvenous lead- and pacemaker pocket-related complications. Initial studies have demonstrated favorable efficacy and safety of currently developed leadless pacing systems, compared to transvenous pacemakers. In the present paper, we review the current evidence and highlight the advantages and disadvantages of this novel technology. New technological advances may allow the next generation of leadless pacemakers to further expand, thereby offering a wireless cardiac pacing in future.

The subcutaneous ICD as an alternative to the conventional ICD system: Initial experience in Greece and a review of the literature.

The introduction of an implantable cardioverter defibrillator (ICD) in clinical practice has revolutionized our therapeutic approach for both primary and secondary prevention of sudden cardiac death (SCD), as it has proven to be superior to medical therapy in treating potentially life-threatening ventricular arrhythmias and has resulted in reduced mortality rates. However, implantation of a conventional ICD carries a non-negligible risk of periprocedural and long-term complications associated with the transvenous ICD leads. The entirely subcutaneous implantable cardioverter defibrillator (S-ICD) has recently emerged as a therapeutic alternative to the conventional ICD for patients with various cardiopathies and who are at high risk of SCD. The main advantage is the avoidance of vascular access and thus avoidance of complications associated with transvenous leads. Patients without pacing indications, such as bradycardia, a need for antitachycardia pacing or cardiac resynchronization, as well as those at higher risk of complications from transvenous lead implantation are perfect candidates for this novel technology. The subcutaneous ICD has proven to be equally safe and effective compared to transvenous ICD systems in early clinical trials. Further technical improvements of the system will likely lead to the expansion of indications and widespread use of this technology. In the present review, we discuss the indications for this system, summarize early clinical experiences and highlight the advantages and disadvantages of this novel technology. In addition, we present the first two cases of subcutaneous cardioverter defibrillator system implantation in Greece.

Transvenous extraction of cardiac rhythm device leads: a report of the experience from a single referral centre in Greece.

INTRODUCTION: As rates of implanted cardiac electronic devices continue to rise, lead extraction procedures are crucial for the management of complications. The optimal method for such procedures has been constantly debated. We sought to review our experience of lead extraction using a conventional technique. METHODS: This was a retrospective study of lead extraction procedures in a major referral centre in Greece. Leads were extracted in a series of 66 consecutive patients (69% men, age range 53-90 years) who visited our centre between August 2008 and June 2012. The extraction procedure was performed in the catheterization lab with a widely used system composed of a locking stylet and sheath. RESULTS: A total of 120 leads were extracted (51 atrial, 69 ventricular) including 19 defibrillator leads and 9 coronary sinus leads. The most frequent indication for lead extraction was infective endocarditis (28 patients, 42%), followed by generator pocket infection (22 patients, 33%), and lead malfunction (16 patients, 24%). Extraction was achieved through the venous entry-site approach in all procedures. The leads were completely extracted in 65 patients (98.5%). Only one complication was recorded: perforation of the right atrium in one patient (1.5%), who eventually underwent emergency cardiac surgery with a good outcome. CONCLUSIONS: Our data confirm that a conventional mechanical technique is highly effective for successful extraction of all types of implanted cardiac electronic device leads and is associated with very limited complications.

Upgrading pacemaker to cardiac resynchronization therapy: an option for patients with chronic right ventricular pacing and heart failure.

INTRODUCTION: Long-term pacing from the right ventricle (RV) has been shown to induce a deleterious effect on left ventricular function. Cardiac resynchronization therapy (CRT) is an established treatment for heart failure (HF) patients. The purpose of this study was to assess the benefit from upgrading to CRT in chronically RV-paced patients with a low left ventricular ejection fraction (LVEF<35%). METHODS: Thirty-seven HF patients (age 71.4 ± 7.7, 26 male), who fulfilled CRT indications, were included. Study subjects had undergone VVI or DDD pacemaker implantation 6.1 ± 5.7 years earlier and were referred to our centre because of worsened clinical condition or a depleted battery. Patients were assessed at baseline and six months after CRT. Evaluation included NYHA classification, functional capacity assessed by six-minute walk test (6 MWT), hospitalization rate and echocardiographic assessment. RESULTS: Biventricular pacing was possible in 34 of the 37 cases (91.7%) who had their device upgraded to CRT-P (n=8) or to CRT-D (n=26). After the implementation of CRT the patients showed a noteworthy clinical improvement. Average NYHA class changed from 3.3 ± 0.6 to 2.5 ± 0.9 (p<0.001), 6 MWT performance increased from 246 ± 105 m to 321 ± 101 m (p<0.001), while six-month hospitalization rate dropped from 1.4 ± 1 to 0.7 ± 0.8 admissions (p<0.001). LVEF increased from 26.3 ± 5.4% to 31.4 ± 6.7% (p<0.001) and left ventricular end-systolic volume changed from 134.3 ± 46 mL to 111.9 ± 41.1 mL (p<0.001). A reduction in QRS duration by 28 ms (p<0.001) was also noted. CONCLUSIONS: RV-paced patients should be closely monitored, and upgrade to CRT should be considered promptly if they develop moderate or severe HF.

Bifocal right ventricular pacing: an alternative way to achieve resynchronization when left ventricular lead insertion is unsuccessful.

PURPOSE: Bifocal pacing in the right ventricle is an option for patients with end-stage heart failure in whom biventricular pacing is not possible, due to failure in left ventricular (LV) lead insertion. The purpose of this prospective study was to document the clinical response of these patients, after bifocal pacing. METHODS: From the patients referred for cardiac resynchronization therapy (CRT), from 2009 to 2010, 13 cardiac CRT candidates who underwent unsuccessful LV lead implantation were included. The bifocal system's leads were implanted in the right atrium, the right ventricular (RV) apex, and the RV outflow tract. Initial patient assessment and follow-up evaluation after 6 months included clinical criteria, echocardiographic indices, and biochemical parameters. RESULTS: From 13 patients (age 68 ± 9 years, nine male), 10 improved clinically. New York Heart Association classification was reduced by one grade (from 3.6 ± 0.5 to 2.8 ± 0.8, p < 0.005 and respectively), while hospitalizations in 6-month time were reduced from three to one (p < 0.001). Six-minute walk test (in meters) increased from 176 ± 86 to 297 ± 91 (p < 0.001) and quality of life improved (EQ-VAS scale changed from 42 ± 12.5 % to 70.8 ± 20.3 %, p < 0.001). Mean shortening in QRS duration was 31.3 ms (from 165.1 ± 16.3 to 133.8 ± 12.7, p < 0.001) and B-type natriuretic peptide (in picograms per milliliter) dropped from 834 ± 350 to 621 ± 283 (p < 0.001). Ejection fraction (in percent) increased from 27.5 ± 4.6 to 33.3 ± 4.4 (p < 0.001), and mitral regurgitation severity decreased by one grade (from 2.7 ± 0.9 to 1.8 ± 0.7, p < 0.05). CONCLUSION: RV bifocal pacing seems to offer a substantial clinical benefit to heart failure patients with traditional CRT indications and could be an alternative option when LV access is unsuccessful.

The role of the implantable loop recorder in the investigation of recurrent syncope.

Recurrent syncope is a common clinical problem. Patients with recurrent syncope frequently undergo extensive investigations that consume significant health care resources. Nevertheless, in a large percentage of patients syncope remains unexplained. The implantable loop recorder is a recognized diagnostic tool that can provide a definitive diagnosis and thus permit specific treatment. We present the case of a woman with recurrent syncope who was referred to our cardiology department for further investigation. Her last episode had led to a fall that caused her serious injuries. The initial routine workup was negative for cardiac, neurologic or metabolic causes of syncope. The implantable loop recorder revealed an arrhythmic origin for the recurrent syncope. The patient was managed appropriately with pacemaker implantation and has remained asymptomatic for one year.