Evolution of ventricular and valve function in patients with right ventricular pacing - A randomized controlled trial comparing leadless and conventional pacing.

BACKGROUND: Leadless pacemakers (PMs) were recently introduced to overcome lead-related complications. They showed high safety and efficacy profiles. Prospective studies assessing long-term safety on cardiac structures are still missing. OBJECTIVE: The purpose of this study was to compare the mechanical impact of Micra with conventional PM on heart function. METHODS: We conducted a non-inferiority trial in patients with an indication for single chamber ventricular pacing. Patients were 1:1 randomized to undergo implantation of either Micra or conventional monochamber ventricular pacemaker (PM). Patients underwent echocardiography at baseline, 6 and 12 months after implantation. Analysis included left ventricular ejection fraction (LVEF), global longitudinal strain (GLS) and valve function. N-terminal-pro hormone B-type natriuretic peptide (NT-pro-BNP) levels were measured at baseline and 12 months. RESULTS: Fifty-one patients (27 in Micra group and 24 in conventional group) were included. Baseline characteristics were similar for both groups. At 12 months, (1) the left ventricular function as assessed by LVEF and GLS worsened similarly in both groups (∆LVEF -10 ± 7.3% and ∆GLS +5.7 ± 6.4 in Micra group vs. -13.4 ± 9.9% and +5.2 ± 3.2 in conventional group) (p = 0.218 and 0.778, respectively), (2) the severity of tricuspid valve regurgitation was significantly lower with Micra than conventional pacing (p = 0.009) and (3) median NT-pro-BNP was lower in Micra group (970 pg/dL in Micra group versus 1394 pg/dL in conventional group, p = 0.041). CONCLUSION: Micra is non inferior to conventional PMs concerning the evolution of left ventricular function at 12-month follow-up. Our data suggest that Micra has a comparable mechanical impact on the ventricular systolic function but resulted in less valvular dysfunction.

Quality of life outcomes in cryoablation of atrial fibrillation-A literature review.

BACKGROUND: Cryoballoon ablation (CRYO) for pulmonary vein isolation (PVI) in atrial fibrillation (AF) has become an established treatment option as alternative for radiofrequency catheter ablation (RFCA). As symptom relief is still the main indication for PVI, quality of life (QoL) is a key outcome parameter. This review summarizes the evidence about the evolution of QoL after CRYO. METHODS: A search for clinical studies reporting QoL outcomes after CRYO was performed on PUBMED and COCHRANE. A total of 506 publications were screened and 10 studies met the in- and exclusion criteria. RESULTS: All studies considered QoL as a secondary endpoint and reported significant improvement in QoL between baseline and 12 months follow-up, independent of the QoL instruments used. The effect size of CRYO on QoL was comparable between studies and present in both paroxysmal and persistent AF. Direct comparison between CRYO and RFCA was limited to two studies, there was no difference between ablation modalities after 12 months FU. Two studies in paroxysmal AF reported outcome beyond 12 months follow-up and QoL improvement was maintained up to 36 months after ablation. There were no long-term data available for persistent AF. CONCLUSION: CRYO of AF significantly improves QoL. The scarce amount of data with direct comparison between subgroups limits further exploration. Assessment of QoL should be considered a primary outcome parameter in future trials with long-term follow-up.

Bacteraemia after leadless pacemaker implantation.

BACKGROUND: Transvenous 3 permanent pacemaker-related infection is a severe condition associated with significant morbidity and mortality. Leadless pacemakers may be more resistant to bacterial seeding during bloodstream infection because of its small surface area and encapsulation in the right ventricle. This study reports the incidence and outcomes of bacteraemia in patients implanted with a Micra leadless pacemaker. We present 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings obtained in a subgroup of patients. METHODS: We report a retrospective cohort study of 155 patients who underwent a Micra TPS implant procedure at the University Hospitals of Leuven between July 2015 and July 2019. We identified the patients who developed an episode of bacteraemia, proved by ≥2 positive blood cultures. RESULTS: Of the 155 patients, 15 patients presented an episode of bacteraemia at a median of 226 days (range: 3-1129) days after the implant procedure. Gram-positive species accounted for 73.3% (n = 11) of the bacteraemia including Staphylococcus (n = 5), Enterococcus (n = 3), and Streptococcus (n = 3). The source of infection was identified in nine patients (60%) including endocarditis in four patients, urinary tract in three patients, and skin in two patients. 18 F-FDG PET/CT imaging performed in six patients did not show sign of infection around the leadless pacemaker. Bacteraemia was resolved in all patients after adequate antibiotherapy. Four patients died early during follow up. For all other patients, there were no recurrence of systemic infection during a median follow up of 263 days (range: 15-1134). CONCLUSION: In our small cohort, no leadless pacemaker endocarditis was observed among patients with bacteraemia.

Premature ventricular contractions cause a position shift in 3D mapping systems: analysis, quantification, and correction by hybrid activation mapping.

AIMS: Using a modified CARTO 3D mapping system, we studied if premature ventricular contractions (PVCs) cause position shifts within the 3D co-ordinate system. We quantified magnitude of the phenomenon and corrected for it, by creating both an activation map that represents the conventional local activation time (LAT) and one corrected for this position shift (hybrid LAT map). METHODS AND RESULTS: We prospectively enrolled patients planned for PVC ablation. Distances between the earliest LAT, the earliest hybrid-LAT, and the best pacemap positions were calculated in a 3D model. Ablation was performed at the best hybrid-LAT location. Efficacy was evaluated by acute response to ablation as well as clinical outcome on 24-h Holter at 1 year. One hundred and twenty-seven LAT-hybrid pairs were studied in 18 patients (age 48.3 ± 18.0 years, 12 female). Baseline PVC burden was 16 ± 12%. The mean position shift between LAT-hybrid and its associated LAT position was 8.9 ± 5.5 mm. The mean position shift between best LAT-hybrid and best pacemap was 6.2 ± 5.0 mm and the mean shift between best conventional LAT and best pacemap was 13.5 ± 7.0 mm (P < 0.0001 for all pairwise comparisons). Exclusive targeting of best LAT-hybrid position resulted in acute abolition of PVC activity in all patients. After 1-year follow-up, mean PVC burden reduction was 16% (baseline) to <1%. CONCLUSION: Premature ventricular contractions cause a position shift in 3D mapping systems compared with the same endocardial position in sinus rhythm. An approach to account for this phenomenon, correct it and target exclusively the adjusted 3D position is feasible and highly efficient in terms of acute and 1-year clinical outcome after radiofrequency ablation.

Determinants of the difficulty of leadless pacemaker implantation.

BACKGROUND: The Micra Transcatheter Pacing System is implanted directly in the right ventricle (RV) through the femoral vein using a steerable transcatheter delivery system. The present study was done to identify determinants of difficult leadless pacemaker implant procedures including operator, patient, and RV anatomical characteristics. METHODS: All patients who underwent a Micra implant from July 2015 to December 2018 at our center were analyzed. From an RV angiogram acquired during implantation, RV geometry including systolic and diastolic volumes and ejection fraction was characterized. The presence of septomarginal trabeculation was noted. RESULTS: One hundred twenty-six patients (mean age: 79 ± 11 years old, mostly male: 77%) were enrolled. Mean Micra RV implant procedure time was 24 ± 23 min, with 1.7 ± 1.3 deployments of the device. No significant change in implant procedure time was observed after the first 30 implants. Eleven patients had a prominent septal component of the septomarginal trabeculation in the RV. Univariate analysis showed that the procedure time was positively correlated with the presence of a prominent septal component of the septomarginal trabeculation (P < .001) or an episode of heart failure (P = .02) and negatively correlated with the number of procedures performed by the operator (P < .001). After multivariable analysis, only the presence of a prominent septal component of the septomarginal trabeculation (P < .001) and the number of procedures performed by the operator (P < .001) were associated with the implant procedure time. CONCLUSIONS: In our experience, implant procedure time of a Micra leadless pacemaker depended on the presence of a prominent septal component of the septomarginal trabeculation and operator experience.

Leadless pacing with Micra TPS: A comparison between right ventricular outflow tract, mid-septal, and apical implant sites.

BACKGROUND: With its steerable transcatheter delivery system, the Micra can be deployed in nonapical positions within the right ventricle, potentially allowing reduction of the paced QRS width. We sought to evaluate the safety and long-term performance of the right ventricular outflow tract (RVOT) pacing using the Micra transcatheter pacing system (TPS). We also compared the paced QRS between RVOT, mid-septal, and apical implant positions. METHODS: All patients who underwent a Micra TPS implantation at the University Hospitals of Leuven were enrolled in this observational study. Right ventricular (RV) position of the device was assessed on per-procedural ventriculography. Paced QRS was analyzed and follow-up completed at 1 month and then every 6 months. RESULTS: Among the 133 patients included (mean follow-up: 13 ± 11 months), 45 were implanted in the RVOT, 58 midseptally, and 30 at the apex. All implant procedures were successful and no pericardial effusion was encountered within the 30 days post-implant. Two major complications were reported with devices implanted at the apex. Pacing impedance was significantly higher in the RVOT compared to the mid-septal and apical position (P < .001). Pacing threshold and R-wave amplitude did not differ over time in either position. The median narrowest paced QRS duration was observed in the RVOT (142 ms) compared to mid-septal (159 ms; P < .001), and apical position (181 ms; P < .001). CONCLUSION: Implantation of the Micra TPS in the RVOT is safe and feasible. Electrical performance over time was comparable to mid-septal and apical positions. The narrowest paced QRS complexes is achieved with RVOT pacing.

Sex differences in rate and rhythm control for atrial fibrillation.

Atrial fibrillation (AF), is the most common sustained arrhythmia and is associated with a substantial increase in morbidity and mortality. Several studies have demonstrated sex-related differences in various aspects, including age at diagnosis, clinical manifestations, management and prognosis. These dissimilarities may dictate different approaches to management and could translate to differences in outcomes. However, similarly to other cardiovascular therapies, there may be a tendency to treat females more conservatively and less aggressively than male patients. The use of oral anticoagulants, for example, is lower in female patients with AF. Electrical cardioversion is less often used. Likewise, despite higher rates of adverse reactions to antiarrhythmic drugs in women, they are less likely to undergo catheter ablations, a well-established therapeutic approach to symptomatic patients with recurrences of AF. In this article, we review sex related dissimilarities in patients with AF. In addition, we discuss various treatment options, and specifically refer to differences in access of treatment, success rates, and potential treatment-related complications.

Differential presentation of atrioventricular nodal re-entrant tachycardia in athletes and non-athletes.

AIMS: Prolonged participation in exercise results in structural and electrical cardiac remodelling. The development of an athlete's heart is recognized as a risk factor for atrial arrhythmias. This study aims to evaluate the impact of athlete heart remodelling on the presentation of atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: A retrospective analysis of an ablation database selecting all patients with an electrophysiologically confirmed diagnosis of AVNRT. Athletes (individuals participating in moderate to intensive sports for ≥3 h per week having done so for ≥5 years) were compared with healthy non-athletes. Atrioventricular nodal re-entrant tachycardia subforms were classified according the methods described by Katritsis and Josephson in 2013 and by Heidbuchel and Jackman in 2014. A total of 504 AVNRT patients were fully characterized, of whom 85 (17%) were athletes. Almost half of the athletes presented with atypical forms of AVNRT, where in non-athletes this frequency was about 20%. There was no difference in acute procedural success among the two groups, but the procedures in athletes were more complex, as reflected by an almost two-fold increase in the use of a long sheath to reach the slow pathway ablation area and a higher recurrence rate in athletes (10% vs. 4%). CONCLUSION: Athletes present more frequently with atypical subforms of AVNRT. This is possibly related to cardiac remodelling with dilatation of the cardiac cavities leading to changed conduction properties in the septal area. Ablation outcome is equally safe in athletes as in non-athletes with similar acute success rates. Athletes experience a higher longer-term recurrence rate.

Combining noninvasive risk stratification parameters improves the prediction of mortality and appropriate ICD shocks.

BACKGROUND: Sudden cardiac death (SCD) results from a complex interplay of abnormalities in autonomic function, myocardial substrate and vulnerability. We studied whether a combination of noninvasive risk stratification tests reflecting these key players could improve risk stratification. METHODS: Patients implanted with an ICD in whom 24-hr holter recordings were available prior to implant were included. QRS fragmentation (fQRS) was selected as measure of myocardial substrate and a high ventricular premature beat count (VPB >10/hr) for arrhythmic vulnerability. From receiver operating characteristics analysis, detrended fluctuation analysis (DFA), turbulence slope, and deceleration capacity were selected for autonomic function. Adjusted Cox regression analysis with comparison of C-statistics was performed to predict first appropriate shock (AS) and total mortality. RESULTS: A total of 220 patients were included in the analysis with an overall follow-up of 4.3 ± 3.1 years. A model including VPB >10/hr, inferior fQRS, and abnormal nonedited DFA was the best for prediction of AS after 1 year of follow-up with a trends toward improvement of the C-statistics compared to baseline (p = 0.055). The risk increased significantly with every abnormal test (HR 1.793, 95%CI 1.255-2.564). A model including fQRS in any region and abnormal edited DFA was the best for prediction of mortality after 3 years of follow-up with significant improvement of the C-statistics (p = 0.023). Each abnormal test was associated with a significant increase in mortality (HR 5.069, 95%CI 1.978-12.994). CONCLUSION: Combining noninvasive risk stratification tests according to their physiological background can improve the risk prediction of SCD and mortality.

QT correction across the heart rate spectrum, in atrial fibrillation and ventricular conduction defects.

BACKGROUND: Incorporation of QTc in clinical decision support systems requires accurate QT-interval correction, also during common electrocardiogram abnormalities as ventricular conduction defects (VCD). We compared the performance and predictive value of QT correction formulas to design a patient-specific QT correction algorithm (QTcA). METHODS: The first ECG in adult patients with sinus rhythm (SR), atrial fibrillation (AF), and ventricular pacing (VP) was collected retrospectively. QT correction was performed with Bazett (QTcB), Fridericia (QTcFri), Framingham, Hodges, and Rautaharju (QTcR) formulas. Correction formulas were compared using QTc/RR linear regression. Adjusted Cox regression was performed to predict 1-year all-cause mortality. RESULTS: A total of 49,737 patients were included (70.0% SR, 24.1% AF, 5.9% VP, 11.1% VCD). Overall 1-year all-cause mortality rate was 11.8%. In patients without VCD or VP, QTcFri showed significantly better heart rate correction, both overall (P < 0.001) and in subgroups by heart rate (bradycardia P ≤ 0.001, normal P ≤ 0.050, tachycardia P ≤ 0.010). Furthermore, QTcFri improved mortality prediction significantly when compared to QTcB (P < 0.001). Patients with VCD or VP QTcR, including correction for QRS duration, had a significant better heart rate correction than QTcB (P ≤ 0.010) and improved mortality prediction significantly compared to all other formulas (P < 0.001). Implementing QTcA, designed based on QTcFri and QTcR depending on the presence of VCD or VP, reduced the patients considered to be at risk by 61.1% when compared to QTcB. CONCLUSIONS: A patient-specific QT correction algorithm would combine accurate heart rate correction, improved predictive value of mortality, and a reduction of patients considered to be at risk.

High-Detailed evaluation of the right atrial anatomy by three-dimensional rotational angiography during ablation procedures for atrioventricular nodal reentrant tachycardia and atrial flutter.

AIM: 3D Rotational angiography (3DRA) allows for detailed reconstruction of atrial anatomy and is often used to facilitate pulmonary vein isolation. This study aimed to reappraise the anatomy of the right atrium (RA) using 3DRA, specifically looking at Koch's triangle and the cavotricuspid isthmus (CTI) in atrio-ventricular reentrant tachycardia (AVNRT) and atrial flutter (AFl) ablation. METHODS AND RESULTS: 3DRA was performed in 97 patients: AVNRT = 51 and AFl = 46. Dimensions of Koch's triangle and CTI were highly variable between individuals but were not different in both ablation groups. RA volume was significantly larger in AFl patients (p = .004) while indexed RA volume to the body surface area (RAVI) was lightly different (p = .024). In univariate Cox analysis, age (p = .003), RAVI (p < .001) and previous ablation of AFl (p = .003) were predictors of AF occurrence . In multivariate Cox analysis, RAVI was the only independent predictor of AF occurrence. RAVI >80 ml/m2 was a strong predictor for AF during follow-up. CONCLUSION: 3DRA allows for detailed per-procedural evaluation of RA anatomy and revealed a great variability in Koch's triangle and CTI dimensions and morphology. RA enlargement as measured by RAVI was an independent predictor for AF occurrence during follow-up.

Genotype-phenotype relationship and risk stratification in loss-of-function SCN5A mutation carriers.

INTRODUCTION: Loss-of-function (LoF) mutations in the SCN5A gene cause multiple phenotypes including Brugada Syndrome (BrS) and a diffuse cardiac conduction defect. Markers of increased risk for sudden cardiac death (SCD) in LoF SCN5A mutation carriers are ill defined. We hypothesized that late potentials and fragmented QRS would be more prevalent in SCN5A mutation carriers compared to SCN5A-negative BrS patients and evaluated risk markers for SCD in SCN5A mutation carriers. METHODS: We included all SCN5A loss-of-function mutation carriers and SCN5A-negative BrS patients from our center. A combined arrhythmic endpoint was defined as appropriate ICD shock or SCD. RESULTS: Late potentials were more prevalent in 79 SCN5A mutation carriers compared to 39 SCN5A-negative BrS patients (66% versus 44%, p = .021), while there was no difference in the prevalence of fragmented QRS. PR interval prolongation was the only parameter that predicted the presence of a SCN5A mutation in BrS (OR 1.08; p < .001). Four SCN5A mutation carriers, of whom three did not have a diagnostic type 1 ECG either spontaneously or after provocation with a sodium channel blocker, reached the combined arrhythmic endpoint during a follow-up of 44 ± 52 months resulting in an annual incidence rate of 1.37%. CONCLUSION: LP were more frequently observed in SCN5A mutation carriers, while fQRS was not. In SCN5A mutation carriers, the annual incidence rate of SCD was non-negligible, even in the absence of a spontaneous or induced type 1 ECG. Therefore, proper follow-up of SCN5A mutation carriers without Brugada syndrome phenotype is warranted.

Prognostic value of electrocardiographic time intervals and QT rate dependence in hypertrophic cardiomyopathy.

INTRODUCTION: Preventing sudden cardiac death (SCD) is one of the main goals in hypertrophic cardiomyopathy (HCM). Many variables have been proposed, however the European and American guidelines do not incorporate any ECG or Holter monitoring derived variables other than the presence of ventricular arrhythmia in their risk stratification models. In the present study we evaluated electrocardiographic parameters in risk stratification of HCM. METHODS AND RESULTS: Novel electrocardiographic parameters including the index of cardio-electrophysiological balance (iCEB), individualized QT correction (QTi) and QT rate dependence were evaluated along with established risk factors. A composite endpoint of SCD was defined as out of hospital cardiac arrest, appropriate ICD shock and sustained ventricular tachycardia. Cox regression analysis was used to evaluate predictors of SCD. Out of the 466 HCM patients, 31 reached the composite endpoint during a follow up of 75 ±â€¯86 months. In a multivariate model, nor iCEB, QTi or QT rate dependence were predictors of SCD. Only male gender (p < 0.01; OR 13.1; CI 1.74-98.83), negative T waves in the inferior leads (p = 0.04; OR 2.51; CI 1.03-6.13) and familial sudden death (p < 0.01; OR 3.03; CI 1.39-6.59) were significant predictors. On top of either the ESC risk score or the 3 traditional 'American risk factors', only male gender was a significant predictor of SCD. CONCLUSION: No ECG or Holter monitoring parameters added in risk stratification for SCD in HCM. However, male gender and negative T waves in the inferior leads are promising novel markers to evaluate in larger cohorts.

Inter- and intra-observer variability of visual fragmented QRS scoring in ischemic and non-ischemic cardiomyopathy.

BACKGROUND: Fragmented QRS (fQRS) on a 12-lead ECG has been linked with adverse outcome. However, the visual scoring of ECGs is prone to inter- and intra-observer variability. METHODS: Five observers, two experienced and three novel, assessed fQRS in 712 digital ECGs, 100 were re-evaluated to assess intra-observer variability. Fleiss and Cohen's Kappa were calculated and compared between subgroups. RESULTS: The inter-observer variability for assessing fQRS in all leads combined was substantial with a Kappa of 0.651. Experienced observers only had a better agreement with a Kappa of 0.823. Intra-observer variability ranged from 0.736 to 0.880. In the subgroup with ventricular pacing the inter-observer variability was even significantly larger when compared to ECGs with normal QRS duration (Kappa 0.493 vs 0.664, p<0.001). CONCLUSION: The visual assessment of QRS fragmentation is prone to inter- and intra-observer variability, mainly influenced by the experience of the observers, the underlying rhythm and QRS morphology.

Monocentric experience of leadless pacing with focus on challenging cases for conventional pacemaker.

AIM: Leadless cardiac pacemaker has been developed to reduce complications related to cardiac pacing and is considered as an alternative to conventional pacemaker although safety and efficacy data in clinical practice are limited. The purpose of this study was to investigate the safety and efficacy profile of Micra Transcatheter Pacing System (TPS) used in daily clinical activity with a focus on challenging cases for conventional pacing. METHODS: A total of 66 patients (46 men, 79.1 ± 9.7 years) having a Class I or II indication for ventricular pacing underwent a Micra TPS implant procedure. All patients were enrolled in a prospective registry. Follow-up visits were scheduled at discharge and after 1, 3, 6 and 12 months. RESULTS: Primary indication for pacing was third degree atrioventricular block (30.3%), sinus node dysfunction (21.2%) or permanent atrial fibrillation with bradycardia (45.5%). The device was successfully implanted in 65 patients (98.5%). During follow-up of 10.4 ± 6.1 months (range 1-23 months), electrical measurements remained stable. Mean pacing capture threshold, pacing impedance and R-wave sensing were respectively 0.57 ± 0.32 V, 580 ± 103 Ohms, 10.62 ± 4.36 mV at the last follow-up. One major (loss of function) and three minor adverse events occurred. Pericardial effusion, dislodgement, device related infection or pacemaker syndrome were not observed. Micra TPS implantation was straightforward for patients with congenital or acquired cardiac and/or vascular abnormalities, previous tricuspid surgery and after heart transplantation. CONCLUSION: Our experience confirms that implantation of Micra is safe and efficient in a real world population including patients who present a challenging condition for conventional pacing.

Introducing ICD-resistant mortality as an end point to evaluate the clinical efficacy of an implantable cardioverter-defibrillator in ischaemic cardiomyopathy.

OBJECTIVE: A new end point called ICD-resistant mortality was evaluated to assess the clinical efficacy of ICD implantations. METHODS AND RESULTS: In 302 ICD patients with ischaemic cardiomyopathy, we investigated which clinical parameters predicted useful ICD implantations using cumulative incidence competing risk analysis. Implantation was deemed clinically useful when the ICD provided appropriate therapy and the patient survived implantation by 1 year and the first shock by 30 days. ICD-resistant mortality (ICDRM) was defined as death within 30 days after the first shock, within 1 year of implantation or without previous appropriate ICD therapy. After 5 years, ICDRM occurred in 23% of implantations, while 36% were clinically useful. After multivariable analysis, ICDRM was associated with LVEF <35% (HR: 2.63; p = .005), beta-blocker dose <50% (HR: 2.0; p = .01) and anterior or diffuse infarct location (HR: 3.61; p = .001 and HR: 2.89; p = .02). Useful ICD implantations were associated with beta-blocker dose <50% (HR: 1.64; p = .02) and non-anterior infarct location (HR: 3.22 vs anterior and 1.59 vs diffuse; combined p<.001). CONCLUSIONS: Five years after implantation, an ICD could be classified as useful in 1 out of 3, while ICDRM occurred in one out of four patients. At 10 years, up to 80% of implantations could be categorized. Lower LVEF was related with significantly higher incidence of ICDRM. Anterior infarcts were associated with more ICDRM and less useful implantations than non-anterior infarcts. Future risk stratification for ICD should focus more on the discrimination between arrhythmic risk, probably preventable by ICDs and ICD-resistant mortality risk.

The impact of changes in LVEF and renal function on the prognosis of ICD patients after elective device replacement.

BACKGROUND: A proportion of patients with an implantable cardioverter-defibrillator (ICD) in prevention of sudden cardiac death will only receive their first appropriate ICD therapy (AT) after device replacement. Clinical reassessment at the time of replacement could be helpful to guide the decision to replace or not in the future. METHODS: All patients with an ICD for primary or secondary prevention in ischemic (ICM) or nonischemic cardiomyopathy were included in a single-center retrospective registry. The association of changes in left ventricular ejection fraction (LVEF; cut-off at 35%), worsening renal function (decrease in estimated glomerular filtration rate > 15 mL/min), and worsening New York Heart Association class at elective device replacement with mortality and AT was analyzed using adjusted Cox regression analysis. RESULTS: A total of 238 (33%) out of 727 patients received elective device replacement (86.1% male, 74.4% ICM, 42.9% primary prevention). During this replacement 20.2% received a device upgrade. The mean time to replacement was 6.4 ± 2.0 years and mean follow-up after replacement was 3.4 ± 3.0 years. Of patients who did not receive AT before replacement 23.1% received their first AT after replacement. Worsening renal function (hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.50-5.18) and a consistently LVEF ≤35% compared to a consistently LVEF >35% (HR 2.15, 95% CI 1.10-4.19) at the time of replacement were independent predictors of mortality. Independent predictors of first AT after replacement could not be identified. CONCLUSION: Although reassessment of LVEF and renal function at replacement can be helpful in predicting total mortality, the clinical utility to guide reimplantation seemed limited. Our experience indicates that approximately 25% of patients received their first AT only after replacement.

Inappropriate ICD shocks do not induce pro-arrhythmic electrocardiographic changes in men.

OBJECTIVES: Longer-term electrocardiographic effects of multiple inappropriate ICD shocks were investigated to study their hypothesized pro-arrhythmic potential. DESIGN: Thirteen male patients with ischemic cardiomyopathy who received ≥2 inappropriate shocks within 24 h and for whom 12-lead ECGs were available both before and within 72h after the inappropriate shocks were analyzed. Exclusion criteria included continuous ventricular pacing, underlying AF, events within 6 weeks after lead implantation and concomitant acute medical problems. RESULTS: A total of 149 inappropriate shocks (mean 11 ± 19) were received. There were no significant differences in any of the measured intervals or morphological indices, nor was there a correlation between the "before-after" differences and the number of shocks received. Non-significant changes showed Percentage of Loop Area increase and relative T-wave Residuum decrease while the opposite changes have previously been associated with arrhythmic risk. CONCLUSIONS: No potentially pro-arrhythmic electrocardiographic changes were found 19 h after multiple inappropriate shocks.