Incidence of ventricular arrhythmias in patients with chronic total coronary occlusion: Results of the VACTOR study.

Background: A chronic total coronary occlusion (CTO) is associated with ventricular arrhythmias (VA) in patients with an implantable cardioverter-defibrillator (ICD). Limited data is available on the incidence of VA in CTO patients without an ICD. Objectives: To investigate the incidence of sustained VA in CTO patients after successful CTO revascularization and in patients with untreated CTO or failed CTO revascularization. Methods: Prospective, multicenter observational pilot study including CTO patients who were not eligible for an ICD and had a left ventricular ejection fraction >35 %. We enrolled patients with a successful CTO revascularization (group A) and patients with untreated CTO or failed CTO revascularization (group B). All patients received an implantable loop recorder with remote monitoring. The primary endpoint was sustained VA. Results: Ninety patients were enrolled (mean age 63 ± 10 years, 83.3 % man, mean LVEF 55 ± 8 %). Group A (n = 45) had a higher prevalence of CTO in the left anterior descending artery in comparison to group B (n = 45) (28.9 % versus 4.4 %, P = 0.002). Other baseline characteristics were similar. During a median follow-up time of 26 months (IQR, 19-35), five patients (5.6 %) had a sustained VA. There was no difference in the incidence of sustained VA between groups (3-year cumulative event rate: 8.8 % (group A) versus 4.5 % (Group B), log-rank P = 0.71). Conclusion: Patients with an CTO, who do not qualify for an ICD, have a substantial risk of sustained VA. In our study the incidence was not different between patients with revascularized and those with untreated CTO.

Distribution of Aortic Root Calcium in Relation to Frame Expansion and Paravalvular Leakage After Transcatheter Aortic Valve Implantation (TAVI): An Observational Study Using a Patient-specific Contrast Attenuation Coefficient for Calcium Definition and Independent Core Lab Analysis of Paravalvular Leakage.

BACKGROUND: Calcium is a determinant of paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI). This is based on a fixed contrast attenuation value while X-ray attenuation is patient-dependent and without considering frame expansion and PVL location. We examined the role of calcium in (site-specific) PVL after TAVI using a patient-specific contrast attenuation coefficient combined with frame expansion. METHODS: 57 patients were included with baseline CT, post-TAVI transthoracic echocardiography and rotational angiography (R-angio). Calcium load was assessed using a patient-specific contrast attenuation coefficient. Baseline CT and post-TAVI R-angio were fused to assess frame expansion. PVL was assessed by a core lab. RESULTS: Overall, the highest calcium load was at the non-coronary-cusp-region (NCR, 436 mm3) vs. the right-coronary-cusp-region (RCR, 233 mm3) and the left-coronary-cusp-region (LCR, 244 mm3), p < 0.001. Calcium load was higher in patients with vs. without PVL (1,137 vs. 742 mm3, p = 0.012) and was an independent predictor of PVL (odds ratio, 4.83, p = 0.004). PVL was seen most often in the LCR (39% vs. 21% [RCR] and 19% [NCR]). The degree of frame expansion was 71% at the NCR, 70% at the RCR and 74% at the LCR without difference between patients with or without PVL. CONCLUSIONS: Calcium load was higher in patients with PVL and was an independent predictor of PVL. While calcium was predominantly seen at the NCR, PVL was most often at the LCR. These findings indicate that in addition to calcium, specific anatomic features play a role in PVL after TAVI.

Accuracy of atrial fibrillation detection by an insertable cardiac monitor in patients undergoing catheter ablation: Results of the BioVAD study.

BACKGROUND: Insertable cardiac monitors (ICMs) are increasingly used to evaluate the atrial fibrillation (AF) burden after catheter ablation of AF. BioMonitor III (BM3) is an ICM with a long sensing vector, which enhances sensing capabilities. The AF detection algorithm of the BM3 is based on R-R interval variability. OBJECTIVE: To evaluate the performance of the AF detection algorithm of BM3 in patients before and after catheter ablation of AF using simultaneous Holter recordings. METHODS: In this prospective study, we enrolled patients scheduled for catheter ablation of paroxysmal or persistent AF. After BM3 implantation, patients had a 4 days Holter registration before and 3 months after ablation. All true AF episodes ≥2 min on the Holter were annotated and matched with BM3 detected AF detections. RESULTS: Thirty-one patients were enrolled (mean age 60 ± 8, 74% male, 68% paroxysmal AF). Fifty-six Holter registrations were performed in 30 patients. Twelve patients demonstrated at least one true AF episode with a total AF duration of 570 h. The AF burden accuracy of BM3 before catheter ablation was 99.6%, with a duration sensitivity of 98.6% and a duration specificity of 99.9%. The AF burden accuracy of BM3 after catheter ablation was 99.8%, with a duration sensitivity of 90.2% and a duration specificity of 99.9%. Overall, the AF burden detected on the Holter and BM3 demonstrated a high Pearson correlation coefficient of 0.996. CONCLUSION: BM3 accurately detects AF burden in patients before and after catheter ablation of AF.

Implantable loop recorders in patients with heart disease: comparison between patients with and without syncope.

OBJECTIVE: Patients with heart disease are at increased risk for sudden cardiac death. Guidelines recommend an implantable loop recorder (ILR) for symptomatic patients when symptoms are sporadic and possibly arrhythmia-related. In clinical practice, an ILR is mainly used in patients with unexplained syncope. We aimed to compare the clinical value of an ILR in patients with heart disease and a history of syncope versus those with non-syncopal symptoms. METHODS: In this observational single-centre study, we included symptomatic patients with heart disease who received an ILR. The primary endpoint was an actionable event which was defined as an arrhythmic event leading to a change in clinical management. The secondary endpoint was an event leading to device implantation. RESULTS: One hundred and twenty patients (mean age 47±17 years, 49% men) were included. The underlying disease substrate was inherited cardiomyopathy (31%), congenital heart disease (28%), channelopathy (23%) and other (18%). Group A consisted of 43 patients with prior syncope and group B consisted of 77 patients with palpitations and/or near-syncope. The median follow-up duration was 19 months (IQR 8-36). The 3-year cumulative event rate was similar between groups with regard to the primary endpoint (38% vs 39% for group A and B, respectively, logrank p=0.54). There was also no difference in the 3-year cumulative rate of device implantation (21% vs 13% for group A and B, respectively, logrank p=0.65). CONCLUSION: In symptomatic patients with heart disease, there is no difference in the yield of an ILR in patients presenting with or without syncope.

Incremental Value of an Insertable Cardiac Monitor in Patients with Hypertrophic Cardiomyopathy with Low or Intermediate Risk for Sudden Cardiac Death.

AIMS: The aim of the present study was to compare the rate of actionable arrhythmic events between patients with hypertrophic cardiomyopathy (HCM) who are monitored with an insertable cardiac monitor (ICM) or Holter monitoring. METHODS: We studied 50 patients (mean age 52 years, 72% men) with HCM at low or intermediate risk for sudden cardiac death (SCD), of whom 25 patients received an ICM between November 2014 and February 2019. We retrospectively identified a control group of 25 patients who were matched on age, sex, and HCM Risk-SCD score category. The mean HCM Risk-SCD score was 3.41 ± 1.31 and 3.31 ± 1.43 for the ICM and Holter groups, respectively. The primary endpoint was an actionable event which was defined as an arrhythmic event resulting in a change in patient management. The secondary endpoint was the occurrence of ventricular tachycardia (VT). RESULTS: The cumulative actionable event rate at 30 months was higher in the ICM group (51 vs. 27%, log-rank p value <0.01). De novo atrial fibrillation requiring oral anticoagulation occurred only in the ICM group (n = 3). Overall, 4 implantable cardioverter-defibrillators were implanted for primary prevention (n = 2 in each group). The cumulative rate of VT episodes at 30 months was similar between groups (23% [ICM group] vs. 42% [Holter group], log-rank p value = 0.71). Furthermore, the characteristics of VT were similar between groups with regard to the number of beats and rate. CONCLUSIONS: In adults with HCM, an ICM will detect more arrhythmic events requiring an intervention than a conventional Holter strategy. In contrast, the diagnostic yield of detecting VT seems similar for both groups.

Outcome of Insertable Cardiac Monitors in Symptomatic Patients with Brugada Syndrome at Low Risk of Sudden Cardiac Death.

INTRODUCTION: There is limited data on the experience with insertable cardiac monitors (ICMs) in patients with Brugada syndrome. OBJECTIVE: To evaluate the outcome of ICM in symptomatic patients with Brugada syndrome who are at suspected low risk of sudden cardiac death (SCD). METHODS: We conducted a prospective single-center cohort study including all symptomatic patients with Brugada syndrome who received an ICM (Reveal LINQ) between July 2014 and October 2019. The main indication for monitoring was to exclude ventricular arrhythmias as the cause of symptoms and to establish a symptom-rhythm relationship. RESULTS: A total of 20 patients (mean age, 39 ± 12 years; 55% male) received an ICM during the study period. Nine patients (45%) had a history of syncope (presumed nonarrhythmogenic), and 5 patients had a recent syncope (<6 months). During a median follow-up of 32 months (interquartile range, 11-36 months), 3 patients (15%) experienced an episode of nonsustained ventricular arrhythmia. No patient died suddenly or experienced a sustained ventricular arrhythmia, and no patient had a recurrence of syncope. Overall, 17 patients (85%) experienced symptoms during follow-up, of whom 10 patients had an ICM-detected arrhythmia. In 4 patients (20%), the ICM-detected arrhythmia was an actionable event. ICM-guided management included antiarrhythmic drug therapy for symptomatic ectopic beats (n = 3), pulmonary vein isolation, and oral anticoagulation for atrial fibrillation (n = 1), electrophysiological study for risk stratification (n = 1), and pacemaker implantation for atrioventricular block (n = 1). CONCLUSIONS: An ICM can be used to exclude ventricular arrhythmias in symptomatic patients with Brugada syndrome at low risk of SCD. Furthermore, an ICM-detected arrhythmia changed clinical management in 20% of patients.

Early detection of ventricular arrhythmias in adults with congenital heart disease using an insertable cardiac monitor (EDVA-CHD study).

BACKGROUND: Sudden cardiac death (SCD) due to ventricular arrhythmias (VA) is an important mode of death in adults with congenital heart disease (CHD). Risk stratification is difficult in this heterogeneous population. Insertable cardiac monitors (ICM) may be useful for risk stratification. The purpose of the present study was to evaluate the use of ICM for the detection of VA in adults with CHD. METHODS: In this prospective single-center observational study we included consecutive adults with CHD deemed at risk of VA who received an ICM between March 2013 and February 2019. The decision to implant an ICM was made in a Heart Team consisting of a cardiac electrophysiologist and a cardiologist specialized in CHD. RESULTS: A total of 30 patients (mean age, 38 ± 15 years; 50% male) received an ICM. During a median follow-up of 16 months, 8 patients (27%) had documented nonsustained VA. Of these 8 patients, 3 (10%) received a prophylactic ICD. Furthermore, ICM-detected arrhythmias were present in 22 patients (73%) leading to a change in clinical management in 16 patients (53%). Besides the patients receiving an ICD, 10 patients (33%) had a change in their antiarrhythmic drugs, 6 patients (20%) underwent an electrophysiology study, and 1 patient (3%) received a pacemaker. CONCLUSIONS: The detection of VA by the ICM contributed to the clinical decision to implant a prophylactic ICD. Furthermore, ICM-detected arrhythmias led to important changes in the clinical management. Therefore, long-term arrhythmia monitoring by an ICM seems valuable for risk stratification in adults with CHD.

Usefulness of a standard 12-lead electrocardiogram to predict the eligibility for a subcutaneous defibrillator.

BACKGROUND: Currently, the eligibility for a subcutaneous implantable defibrillator (S-ICD) system relies on a pre-implant vector screening based on the automated screening tool (AST). We investigated which 12-lead ECG characteristics are associated with eligibility for an S-ICD in a heterogeneous population at risk for sudden cardiac death (SCD). The goal is to determine patient eligibility for S-ICD using the standard 12-lead ECG, thereby avoiding additional AST screening. METHODS: We evaluated the eligibility for an S-ICD in 254 consecutive patients at risk for SCD. We identified 12-lead ECG parameters which were independently associated with AST passing (≥1 vector) using multivariable logistical regression analysis in our derivation cohort. The final model was tested in a separate validation cohort. RESULTS: The overall passing rate was 92% in our derivation cohort. Independent 12-lead ECG characteristics associated with AST passing were QRS ≤ 130 ms, absence of QRS/T discordance in lead II and R/T-ratio ≥3.5 in lead II. Eighty-three of 254 patients (33%) fulfilled these three criteria and had a passing rate of 100%. Of the validation cohort, 37 of 60 patients (62%) fulfilled all three criteria and also had a passing rate of 100%. The interobserver agreement for applying the ECG model was 90% (Cohen's Kappa = 0.80). CONCLUSION: Using the standard 12-lead ECG, we developed a simple screening model with a high specificity for S-ICD eligibility. Our results suggest that patients who fulfill the three ECG criteria do not need additional AST-screening.

Impact of device-host interaction on paravalvular aortic regurgitation with different transcatheter heart valves.

AIMS: We sought to evaluate the interaction of different aortic root phenotypes with self-expanding (SEV), balloon-expandable (BEV) and mechanically expanded (MEV) and the impact on significant aortic regurgitation. METHODS AND RESULTS: We included 392 patients with a SEV (N = 205), BEV (N = 107) or MEV (N = 80). Aortic annulus eccentricity index and calcification were measured by multi-slice CT scan. Paravalvular aortic regurgitation was assessed by contrast aortography (primary analysis) and transthoracic echocardiography (secondary analysis). In mildly calcified roots paravalvular regurgitation incidence was similar for all transcatheter heart valves (SEV 8.4%; BEV 9.1%; MEV 2.0% p = 0.27). Conversely, in heavily calcified roots paravalvular regurgitation incidence was significantly higher with SEV (SEV 45.9%; BEV 0.0%; MEV 0.0% p < 0.001). When paravalvular regurgitation was assessed by TTE, the overall findings were similar although elliptic aortic roots were associated with more paravalvular regurgitation with SEV (20.5% vs. BEV 4.5% vs. MEV 3.2%; p = 0.009). CONCLUSIONS: In heavily calcified aortic roots, significant paravalvular aortic regurgitation is more frequent with SEV than with BEV or MEV, but similar in mildly calcified ones. These findings may support patient-tailored transcatheter heart valve selection. CLASSIFICATIONS: Aortic stenosis; multislice computed tomography; transcatheter aortic valve replacement; paravalvular aortic regurgitation. CONDENSED ABSTRACT: We sought to evaluate the interaction of different aortic root phenotypes with self-expanding (SEV), balloon-expandable (BEV) and mechanically expanded (MEV) and the impact on significant aortic regurgitation. We included 392 patients with a SEV (N = 205), BEV (N = 107) or MEV (N = 80). Aortic annulus eccentricity index and calcification were measured by multi-slice CT scan. Paravalvular aortic regurgitation was assessed by contrast aortography and transthoracic echocardiography. We found that in heavily calcified aortic roots, significant paravalvular aortic regurgitation is more frequent with SEV than with BEV or MEV, but similar in mildly calcified ones.

Insertable cardiac monitors: current indications and devices.

INTRODUCTION: Recurrent unexplained syncope is a well-established indication for an insertable cardiac monitor (ICM). Recently, the indications for an ICM have been expanded. AREAS COVERED: This review article discusses the current indications for ICMs and gives an overview of the latest generation of commercially available ICMs. EXPERT COMMENTARY: The 2018 ESC Syncope guidelines have expanded the indications for an ICM to patients with inherited cardiomyopathy, inherited channelopathy, suspected unproven epilepsy, and unexplained falls. ICMs are also increasingly used for the detection of subclinical atrial fibrillation (AF) in patients with cryptogenic stroke. Whether treatment of subclinical AF (SCAF) with oral anticoagulation prevents recurrent stroke is yet unknown. The current generation of ICMs are smaller, easier to implant, have better diagnostics, and are capable of remote monitoring. The Reveal LINQ (Medtronic) is the smallest ICM and has the most extensive performance and clinical data. The BioMonitor 2 (Biotronik) is the largest ICM but has excellent R-wave amplitudes, longest longevity, and reliable remote monitoring. The Confirm Rx (Abbott) is capable to provide mobile data transmission enabled by a smartphone app. Future generation of ICMs will incorporate heart failures indices to facilitate remote monitoring of heart failure patients.

Frequency of Need for Antitachycardia or Antibradycardia Pacing or Cardiac Resynchronization Therapy in Patients With a Single-Chamber Implantable Cardioverter-Defibrillator.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is unable to deliver antitachycardia pacing (ATP), bradycardia pacing, and cardiac resynchronization therapy (CRT). However, little is known about the proportion of patients that develop the need for 1 of these features. We evaluated the potential suitability for a S-ICD at the time of first replacement in a cohort of patients with a transvenous single-chamber device who did not need bradycardia pacing at the time of implantation. The study cohort consisted of patients who received a transvenous single-chamber ICD between 1998 and September 2017. The primary end point was a combined end point of the need for atrial or ventricular pacing, development of a CRT indication, or termination of ventricular arrhythmias by ATP delivery. During a mean follow-up of 5.6 ± 1.9 years, 78 of 254 patients (31%) reached the primary end point. The 7 years' cumulative S-ICD suitability rate was 65.6% (95% confidence interval [CI] 58.5% to 71.7%). Event rates were 9.5% (95% CI 6.5% to 13.9%) at 1-year follow-up, and 28.0% (95% CI 22.8% to 34.2%) at 5 years' follow-up. For individual end points, incidence rates were 1.8 (95% CI 1.2 to 2.6) per 100-patient-years for CRT, 0.3 (95% CI 0.1 to 0.8) per 100-patient-years for pacing-dependency, and 4.9 (95% CI 3.8 to 6.3) per 100-patient-years for appropriate ATP therapy. No baseline variables for predicting S-ICD unsuitability were found. In conclusion, at the time of the first replacement, 69% of the patients with a single-chamber device would have been clinically eligible for the S-ICD. Incidence rates of developing a bradycardia pacing and CRT indication are low.

Evaluation of a novel automatic screening tool for determining eligibility for a subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: The manufacturer has developed a new ECG screening tool to determine eligibility for the subcutaneous ICD (S-ICD), the "automatic screening tool" (AST), which may render manual ECG-screening unnecessary. The aim of the study was to determine the eligibility for the S-ICD using two methods (manual ECG-screening versus AST) in different patient categories including patients with cardiomyopathy, congenital heart disease and inherited primary arrhythmia syndrome. METHODS: We prospectively evaluated the ECG suitability for an S-ICD in consecutive patients at our outpatient clinic between February and June 2017. The primary endpoint of the study was ECG eligibility defined as at least 1 successful vector in both supine and sitting postures. RESULTS: A total of 254 patients (167 men; mean age 45 ±â€¯16 years) were screened using both methods. Overall, there was a high ECG eligibility using either method (93% versus 92%, P = 0.45). Overall agreement between both methods was 94%. Patients with hypertrophic cardiomyopathy (HCM) more often had a failed screening test using either test in comparison to the patients without HCM (manual: odds ratio [OR] 3.3, 95% confidence interval [CI] 1.2-9.3, P = 0.02; AST: OR 3.0, 95% CI 1.2-7.6, P = 0.02). CONCLUSION: AST showed a high agreement with manual ECG-screening for S-ICD. Overall there was a high ECG eligibility for S-ICD, although patients with HCM had a lower passing rate irrespective of the screening method.

Value of implantable loop recorders in patients with structural or electrical heart disease.

PURPOSE: In patients with structural heart disease (SHD) or inherited primary arrhythmia syndrome (IPAS), the occurrence of unexplained syncope or palpitations can be worrisome as they are at increased risk of sudden cardiac death. An implantable loop recorder (ILR) can be a useful diagnostic tool. Our purpose was to compare the diagnostic yield, arrhythmia mechanism, and management in patients with SHD, patients with IPAS, and those without heart disease. METHODS: Retrospective single-center study in consecutive patients who underwent an ILR implantation. RESULTS: Between March 2013 and December 2016, a total of 94 patients received an ILR (SHD, n = 20; IPAS, n = 14; no SHD/IPAS, n = 60). The type of symptoms at the time of implantation was similar between groups. During a median follow-up of 10 months, 45% had an ILR-guided diagnosis. Patients with IPAS had a lower diagnostic yield (14%) in comparison to the other groups (no SHD/IPAS 47%, P = 0.03; SHD 60%, P = 0.01, respectively). Furthermore, patients with SHD had a higher incidence of nonsustained VT in comparison to patients without SHD/IPAS (30 versus 3%, P < 0.01). ILR-guided therapy was comparable between groups. In the SHD group, a high proportion (10%) received an implantable cardioverter-defibrillator; however, this was not statistically significantly higher than the other groups (no SHD/IPAS 3%, IPAS 0%, P = 0.08). CONCLUSIONS: In comparison to patients without heart disease, the diagnostic yield of an ILR was lower in patients with IPAS and the prevalence of ILR-diagnosed nonsustained VT was higher in patients with SHD.

Increased risk of ventricular arrhythmias in survivors of out-of-hospital cardiac arrest with chronic total coronary occlusion.

BACKGROUND: Chronic total occlusion (CTO) is common in out-of-hospital cardiac arrest (OHCA) survivors with coronary artery disease. It is unclear whether CTO contributes to ventricular arrhythmias in this population. OBJECTIVE: This study sought to evaluate the impact of unrevascularized CTOs on the occurrence of appropriate implantable cardioverter-defibrillator (ICD) therapy and all-cause mortality in OHCA survivors with coronary artery disease. METHODS: This was a retrospective study that included all consecutive OHCA survivors with coronary artery disease who received an ICD from December 1999 until June 2015. Study end points were appropriate ICD therapy and all-cause mortality. RESULTS: We identified 217 OHCA survivors (mean age 63 ± 10 years; 187 men (86%)) with coronary artery disease. Unrevascularized CTO was present in 71 of 217 patients (33%) at the time of ICD implantation. During a median follow-up of 61 months (interquartile range, 28-97 months), 57 of 217 patients (26%) experienced an appropriate ICD therapy. Patients with CTO had a higher incidence of appropriate ICD therapy in comparison to patients without CTO (log-rank, P = .002). Multivariate Cox regression analysis identified CTO (hazard ratio 2.07; 95% confidence interval 1.23-3.50; P = .007) as an independent predictor of appropriate ICD therapy. The presence of CTO was not associated with a higher mortality rate (log-rank, P = .18). CONCLUSIONS: In OHCA survivors with coronary artery disease receiving an ICD for secondary prevention, CTO was an independent predictor for the occurrence of ventricular arrhythmias but not for mortality.