Petros Arsenos

Implantable cardioverter defibrillator therapy activation for high risk patients with relatively well preserved left ventricular ejection fraction. Does it really work

BACKGROUND Current guidelines for the primary prevention of sudden cardiac death have used a left ventricular ejection fraction (LVEF) ≤ 35% as a critical point to justify implantable cardioverter defibrillator (ICD) implantation in post myocardial infarction patients and in those with nonischemic dilated cardiomyopathy. We compared mortality and ICD activation rates among different ICD group recipients using a cut-off value for LVEF ≤ 35%. METHODS We followed up for a mean period of 41.1 months 495 ICD recipients (442 males, 65.6 years old, 68.9% post myocardial infarction patients, 422 with LVEF ≤ 35%). Prevention was considered primary in patients who fulfilled guidelines criteria or had inducible ventricular arrhythmia during programmed ventricular stimulation for patients with LVEF >35%. RESULTS Over the course of the trial, 84 of 495 patients died; 69 experienced cardiac death (6 sudden) and 15 non cardiac death. ICD recipients with LVEF ≤ 35% compared to those with preserved LVEF (mean LVEF=43%) had a greater incidence of total mortality (18% vs. 11%, log rank p=0.028) and cardiac death (15.4% vs. 5.5%, log rank p=0.005). There was no difference in the incidence for appropriate device therapy between patients with LVEF ≤ 35% and those with LVEF >35% (56.9% vs. 65.8%, log rank p=0.93). In the multivariate analysis the presence of advanced New York Heart Association stage predicted both total mortality (HR=2.69, 95% CI 1.771-4.086) and cardiac death (HR=3.437, 95% CI 2.163-5.463). CONCLUSIONS ICD therapy may protect heart failure patients at early stages from arrhythmic morbidity and mortality, based on an electrophysiology-guided risk stratification approach.

Primary prevention of sudden cardiac death in a nonischemic dilated cardiomyopathy population: reappraisal of the role of programmed ventricular stimulation.

Background— We considered the role of programmed ventricular stimulation in primary prevention of sudden cardiac death in an idiopathic dilated cardiomyopathy population. Methods and Results— One hundred fifty-eight patients with idiopathic dilated cardiomyopathy underwent programmed ventricular stimulation. Ventricular tachycardia/ventricular fibrillation was triggered in 44 patients (group I, 27.8%) versus 114 patients (group II), where ventricular tachycardia/ventricular fibrillation was not induced. Sixty-nine patients with idiopathic dilated cardiomyopathy underwent implantable cardioverter-defibrillator (ICD) implantation: 41/44 in group I and 28/114 in group II. The major end points of the study were overall mortality and appropriate ICD activation. Overall mortality during the 46.9 months of mean follow-up was not significantly different between the 2 groups. Patients with left ventricular ejection fraction ≤35% (n=119) demonstrated a higher overall mortality rate compared with the patients with left ventricular ejection fraction >35% (n=39; 16.8% versus 10.3%, log-rank P =0.025). Advanced New York Heart Association class (III and IV versus I and II) was the single independent and strongest prognostic factor of overall mortality (hazard ratio, 11.909; P <0.001; confidence interval, 3.106–45.65), as well as of cardiac mortality (hazard ratio, 14.787; P =0.001; confidence interval, 2.958–73.922). Among ICD recipients, ICD activation rate was significantly higher in group I compared with group II (30 of 41 patients–73.2% versus 5 of 28 patients–17.9%; log-rank P =0.001), either in the form of antitachycardia pacing (68.3% versus 17.9%; log-rank P =0.001) or in the shock delivery form (51.2% versus 17.9%; log-rank P =0.05). Induction of ventricular tachycardia/ventricular fibrillation during programmed ventricular stimulation in contrast to left ventricular ejection fraction was the single independent prognostic factor for future ICD activation (hazard ratio, 4.195; P =0.007; confidence interval, 1.467–11.994). Conclusions— Inducibility of ventricular tachycardia/ventricular fibrillation was associated with an increased likelihood of subsequent ICD activation and sudden cardiac death surrogate.Background—We considered the role of programmed ventricular stimulation in primary prevention of sudden cardiac death in an idiopathic dilated cardiomyopathy population. Methods and Results—One hundred fifty-eight patients with idiopathic dilated cardiomyopathy underwent programmed ventricular stimulation. Ventricular tachycardia/ventricular fibrillation was triggered in 44 patients (group I, 27.8%) versus 114 patients (group II), where ventricular tachycardia/ventricular fibrillation was not induced. Sixty-nine patients with idiopathic dilated cardiomyopathy underwent implantable cardioverter-defibrillator (ICD) implantation: 41/44 in group I and 28/114 in group II. The major end points of the study were overall mortality and appropriate ICD activation. Overall mortality during the 46.9 months of mean follow-up was not significantly different between the 2 groups. Patients with left ventricular ejection fraction ⩽35% (n=119) demonstrated a higher overall mortality rate compared with the patients with left ventricular ejection fraction >35% (n=39; 16.8% versus 10.3%, log-rank P=0.025). Advanced New York Heart Association class (III and IV versus I and II) was the single independent and strongest prognostic factor of overall mortality (hazard ratio, 11.909; P<0.001; confidence interval, 3.106–45.65), as well as of cardiac mortality (hazard ratio, 14.787; P=0.001; confidence interval, 2.958–73.922). Among ICD recipients, ICD activation rate was significantly higher in group I compared with group II (30 of 41 patients–73.2% versus 5 of 28 patients–17.9%; log-rank P=0.001), either in the form of antitachycardia pacing (68.3% versus 17.9%; log-rank P=0.001) or in the shock delivery form (51.2% versus 17.9%; log-rank P=0.05). Induction of ventricular tachycardia/ventricular fibrillation during programmed ventricular stimulation in contrast to left ventricular ejection fraction was the single independent prognostic factor for future ICD activation (hazard ratio, 4.195; P=0.007; confidence interval, 1.467–11.994). Conclusions—Inducibility of ventricular tachycardia/ventricular fibrillation was associated with an increased likelihood of subsequent ICD activation and sudden cardiac death surrogate.

Prognostic value of programmed ventricular stimulation for sudden death in selected high risk patients with structural heart disease and preserved systolic function

No recommendations exist regarding the proper management of pa-tients with structural heart disease and preserved systolic function,namely post-myocardial infarction (MI) patients with left ventricularejection fraction (LVEF) N40% and dilated cardiomyopathy (DCM)patients with LVEF ≥40% [1]. Between January 2004 and March 2011,we assessed the prognostic role of programmed ventricular stimulation(PVS) in 69 post-MI and 42 DCM patients with preserved LVEF (96males, 65.8 years old, mean LVEF 46 ± 4.5). Specifically, we included62 patients with syncope (n = 36) or presyncope (n = 26) andnon-conclusive 12-lead ECG, Holter monitoring, echocardiographicstudy and tilt table testing as well as 49 asymptomatic patients with ≥1episodes ofnonsustained ventriculartachycardia (NSVT)(≥3 consecu-tive beats at a rate ≥120 bpm) or ≥30 premature ventricularcomplexes/hour on 24-h Holter monitoring. Active ischemia wasexcluded in post-MI patients. DCM diagnosis was based on clinical,echocardiographic and angiographic findings. The study was approvedby the Medical Research Ethics Committee of our Institution and wascarried out in accordance with the Declaration of Helsinki. All subjectswere informed in detail, agreed to participate and signed an informedconsent form.Antiarrhythmics,prescribedbythereferringphysiciansin23patients,were discontinued before the study. Stimulation protocol consisted of upto triple extrastimuli (S2S3S4) delivered at two paced cycle lengths(550 ms and 400 ms) at the right ventricular apex and outflow tract.Extrastimuliwereappliedafterasix-beatdrivetrainwitha2-sinterdrivepause. In DCM patients where no sustained ventricular tachyarrhythmiawas triggered, PVS was repeated after intravenous isoproterenoladministration (1–4 μg/kg/min) [2]. The presence of either sinus and/or atrioventricular node disease was ascertained based on abnormalelectrophysiological parameters [3].When sustained monomorphic VT for post-MI patients or sustainedVT/ventricular fibrillation (VF) for DCM patients was triggered duringPVS, an implantable cardioverter–defibrillator (ICD) was offered andprogrammed on two consecutive zones: an antitachycardia pacing(ATP)zone(VTdetectioncyclelengthof375±40msanddetectionin-terval of 16/16 or 24/24 beats), and an initial shock zone (VF detectioncycle length of 300 ± 30 ms and detection interval of 18/24). Themajor end-points were the incidence of cardiac death and SCD, as wellas the appropriate first ICD activation for implanted patients. Recur-rence of syncope was examined in patients with syncope/presyncopeat baseline.Sustained monomorphic VT was induced in 23/69 (33.3%) post-MIpatients, more frequently in those with NSVT in Holter monitoring(42.5%vs. 20.7%, p = 0.058). ICD was implanted in all induced patientswhile a pacemaker was also implanted in 16 symptomatic post-MI pa-tients with sinus node and/or atrio-ventricular node disease (Fig. 1).Sustained monomorphic VT was induced in 8 and polymorphic VT/VFin 5 of the 42 DCM patients (VT/VF induction rate 31%). ICD wasimplanted in 10/13 induced patients (3 asymptomatic patients deniedimplantation) and a pacemaker in 7 symptomatic patients (Fig. 1).Mean follow-up period was 52.3 months. During that period, 1 in-ducible DCM patient, that denied ICD implant, experienced SCD and 3patients experienced non-cardiac death. None of the non-inducible pa-tientsatbaseline(46post-MIand29DCMpatients)referredrecurrenceor new-onset syncope or pre-syncope or experienced SCD or cardiac

Effect of biventricular pacing on ventricular repolarization and functional indices in patients with heart failure: lack of association with arrhythmic events

AIMS We prospectively assessed the effects of biventricular (BiV) pacing on electrocardiographic (ECG) and vectorcardiographic (VCG) descriptors of ventricular depolarization and repolarization and their association with appropriate implantable cardioverter defibrillator (ICD) activation. METHODS AND RESULTS We studied 70 consecutive heart failure (HF) (37 ischaemic) patients (64 males, age 66.3 years) with a history of syncope or sustained ventricular tachycardia (VT) who underwent implantation of a BiV-ICD. An invasive electrophysiological study (EPS) was performed before the implantation and 12-lead digital ECGs before and 30 days after implantation. Serial echocardiographic studies were performed. Follow-up duration was 1 year. Maximum (P < 0.001) and minimum (P = 0.004) QT intervals were significantly decreased, whereas QT dispersion was not altered (P = 0.086). QRS duration was shortened (P < 0.001), whereas QRS dispersion was significantly decreased (P = 0.034). Spatial T and QRS vector amplitudes decreased (P < 0.001, for both), whereas the spatial QRS-T angle was not affected (P = 0.671). Twenty-seven (38.6%) patients, experienced appropriate ICD therapies during follow-up. None of the ECG or VCG parameters (pre- or post-implant) were able to identify patients with appropriate ICD therapies during follow-up. Only the presence of a previous episode of sustained VT (spontaneous or inducible on EPS) was strongly associated with appropriate ICD therapies (multivariate P = 0.00 014; odds ratio 24.5). CONCLUSION Improvement or no alteration of ECG and VCG descriptors of ventricular depolarization and repolarization was demonstrated after implantation of a BiV-ICD in HF patients. None of these parameters were associated with appropriate ICD therapies, whereas a previous episode of VT or induction of sustained VT on EPS predicted appropriate ICD treatments.

Deceleration Capacity of Heart Rate Predicts Arrhythmic and Total Mortality in Heart Failure Patients

Deceleration capacity (DC) of heart rate proved an independent mortality predictor in postmyocardial infarction patients. The original method (DCorig) may produce negative values (9% in our analyzed sample). We aimed to improve the method and to investigate if DC also predicts the arrhythmic mortality.

Clinical Determinants of Electrocardiographic and Spatial Vectorcardiographic Descriptors of Ventricular Repolarization in Healthy Children

Background: Although the association of repolarization alterations to the development of life‐threatening ventricular arrhythmias has received considerable research attention, there is paucity of data regarding what may be considered as normal, especially in children.

Electrophysiologic testing guided risk stratification approach for sudden cardiac death beyond the left ventricular ejection fraction

Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators (ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death.

Leadless Pacing System: Initial experience with a novel technology in Greece

lease cite this article in press as: Sid ociety of Cardiology (2017), http:// tp://dx.doi.org/10.1016/j.hjc.2017 09-9666/a 2017 Hellenic Society of ense (http://creativecommons.org/ Leadless pacing systems have recently emerged as a reliable therapeutic alternative to conventional pacemakers in providing therapy for patients with bradyarrhythmias. Initial studies demonstrate favorable efficacy and safety results compared to transvenous pacemakers. We report the first six cases of a leadless pacemaker system (Micra Transcatheter Pacing System, Medtronic, Minneapolis, MN, USA) implantation in Greece that took place in the electrophysiology laboratory of Hippokrateion General Hospital of Athens between April and November 2016. Because of the relatively high cost of leadless pacemakers compared to the conventional ones, the use of this technology is still limited in Greece, and currently such implantations are restricted mostly to patients who present with severe access problems, unlikely to be overcome by conventional transvenous implantation techniques. Data of our patients are presented in Table 1. Procedure: Implantation was performed under fluoroscopy, after obtaining informed consent from the patients, with local anesthesia. After introducing a 24-French sheath into the right femoral vein, a deflectable delivery catheter with the pacemaker adjusted on its distal part was advanced through the inferior vena cava and the right atrium to the right ventricle (RV). Subsequently, the outer sheath was retracted, allowing the device tines to be deployed, fixing the pacemaker in the right ventricular trabeculae. Adequate fixing of the system was confirmed mechanically by the “tug-test” while the pacemaker still

Prevalence of late potentials on signal-averaged ECG in patients with psychiatric disorders

BACKGROUND Sudden cardiac death (SCD) occurs three times more often in psychiatric patients than in the general population. QRS fragmentation (QRSfr) and signal-averaged electrocardiography (SAECG) are simple, inexpensive, readily available tools for detecting the presence of abnormal depolarization and late potentials (LPs) in these patients, a result of either the underlying disease or treatment. METHODS Frequency of LP detection by SAECG and QRSfr was studied in 52 psychiatric patients and compared with 30 healthy (without known structural heart disease or occurrence of ventricular arrhythmia) controls. Patients were then prospectively followed up and incidence of SCD was recorded. RESULTS LP prevalence was significantly higher in patients than in controls (16/52-31% vs 2/30-7%, p=0.012), while QRSfr was similar between these two groups (p=0.09). Of the LP presence criteria, the root mean square value at terminal 40msec of the QRS (RMS40) was significantly lower in patients (32μV, SD=19μV, vs 46μV, SD=32μV, p=0.015). Among patients, no differences were noted between the LP positive and negative groups regarding age, sex, number of medications, class of antipsychotics and defined daily doses. Mean follow-up was 46months (SD=11) and during it 3 patients suffered SCD. Although 2 SCD victims had both LPs and QRSfr concurrently present, neither of them, nor their simultaneous presence could definitely account for the events. CONCLUSIONS LP prevalence in psychiatric patients was significantly higher than in controls. SAECG performance was feasible in all cases and constitutes a readily available tool for assessing myocardial electrophysiological alterations in this patient group.

Diagnosis and management of phantom tachycardias based on an electrophysiologically guided approach

BACKGROUND Non-documented palpitations, or phantom tachycardias, are palpitations deemed to be of unknown origin after evaluation with conventional diagnostic tools, such as 12-lead electrocardiogram and Holter recordings. Our aim was to determine the diagnostic value of an electrophysiologic study (EPS) and its role in the management of patients presenting with non-documented palpitations. METHODS We performed EPS in 78 consecutive patients with repeatable, poorly tolerated symptoms of paroxysmal, non-documented tachycardia, the absence of structural heart disease and at least one 24-h Holter recording. The duration and frequency of palpitations was registered in each patient. RESULTS Long-lasting palpitations (>1 hour) were present in 15.4% of patients. Half of patients reported symptoms less often than once per week. Only 13/78 patients (16.6%) had normal EPS findings, while dual pathways at the AV node ± echo beats were identified in another 13 patients without inducible tachycardia. At least one tachycardia event was induced in 52 patients (66.6%). AVNRT was provoked in 32 patients (41.2%). Ablation was performed in 14/52 patients with inducible tachycardia (26.9%). Slow pathway ablation was also performed in three patients with dual AV pathways and atrial echo-beats but without provoked tachycardia. Follow-up data were available in 52 patients, and 84.6% had fewer or no clinical recurrences. CONCLUSIONS EPS is safe and of enhanced diagnostic value in patients with unexplained palpitations because only 1/6 had negative results. EPS also provided an explanation about the mechanism of arrhythmia and successfully guided the management of these patients, as well as enhanced improvement in the quality of life.