Prevalence of sleep-disordered breathing in patients with mitral regurgitation and the effect of mitral valve repair.

PURPOSE: The relationship between chronic heart failure and sleep-disordered breathing (SDB) has been frequently described. However, little is known about the association of mitral regurgitation (MR) and SDB or the impact of transcatheter mitral valve repair (TMVR) on SDB. Our aims were first to determine the prevalence of SDB in patients with MR, and second to determine the effect of TMVR on SDB. METHODS: Patients with MR being evaluated for TMVR at the University Hospital Bonn underwent polygraphy (PG) to determine the prevalence of SDB. After TMVR, a subset of patients was followed up with transthoracic echocardiography (TTE) and PG to evaluate the effect of TMVR on SDB. RESULTS: In 53 patients, mean age was 76.0 ± 8.5 years and 62% were male. Patients predominantly had more than moderate mitral regurgitation (94%). SDB was highly prevalent (68%) with predominantly central sleep apnoea (CSA, 67%). After TMVR in 15 patients, the apnoea/hypopnoea index (AHI) and central apnoea index (AI) were significantly reduced among patients with SDB (AHI - 8.0/h, p = 0.021; central AI - 6.9/h, p = 0.046). The left atrial volume index (LAVI) at baseline was significantly higher in patients with CSA than in patients with obstructive sleep apnoea (OSA) and was significantly reduced after TMVR (63.5 ml/m2 ± 27.2 vs. 38.3 ml/m2 ± 13.0; - 18.4 ml/m2, p = 0.027). CONCLUSION: SDB, especially CSA, is highly prevalent in patients with mitral regurgitation. In the follow-up cohort TMVR led to a significant reduction of the AHI, predominantly of central events. The findings of the study suggest that TMVR may be a suitable therapy not only for MR but also for the accompanying CSA. LAVI may be a useful indicator for CSA in patients with MR.

Cardiovascular magnetic resonance determinants of ventricular arrhythmic events after myocardial infarction.

AIMS: To non-invasively characterize, by means of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), scar differences, and potential variables associated with ventricular tachycardia (VT) occurrence in chronic post-myocardial infarction (MI) patients. METHODS AND RESULTS: A case-control study was designed through retrospective LGE-CMR data analysis of chronic post-MI patients (i) consecutively referred for VT substrate ablation after a first VT episode (n = 66) and (ii) from a control group (n = 84) with no arrhythmia evidence. The myocardium was characterized differentiating core, border zone (BZ), and BZ channels (BZCs) using the ADAS 3D post-processing imaging platform. Clinical and scar characteristics, including a novel parameter, the BZC mass, were compared between both groups. One hundred and fifty post-MI patients were included. Four multivariable Cox proportional hazards regression models were created for total scar mass, BZ mass, core mass, and BZC mass, adjusting them by age, sex, and left ventricular ejection fraction (LVEF). A cut-off of 5.15 g of BZC mass identified the cases with 92.4% sensitivity and 86.9% specificity [area under the ROC curve (AUC) 0.93 (0.89-0.97); P < 0.001], with a significant increase in the AUC compared to other scar parameters (P < 0.001 for all pairwise comparisons). Adding BZC mass to LVEF allowed to reclassify 33.3% of the cases and 39.3% of the controls [net reclassification improvement = 0.73 (0.71-0.74)]. CONCLUSIONS: The mass of BZC is the strongest independent variable associated with the occurrence of sustained monomorphic ventricular tachycardia in post-MI patients after adjustment for age, sex, and LVEF. Border zone channel mass measurement could permit a more accurate VT risk stratification than LVEF in chronic post-MI patients.

Accuracy of left atrial fibrosis detection with cardiac magnetic resonance: correlation of late gadolinium enhancement with endocardial voltage and conduction velocity.

AIMS: Myocardial fibrosis is a hallmark of atrial fibrillation (AF) and its characterization could be used to guide ablation procedures. Late gadolinium enhanced-magnetic resonance imaging (LGE-MRI) detects areas of atrial fibrosis. However, its accuracy remains controversial. We aimed to analyse the accuracy of LGE-MRI to identify left atrial (LA) arrhythmogenic substrate by analysing voltage and conduction velocity at the areas of LGE. METHODS AND RESULTS: Late gadolinium enhanced-magnetic resonance imaging was performed before ablation in 16 patients. Atrial wall intensity was normalized to blood pool and classified as healthy, interstitial fibrosis, and dense scar tissue depending of the resulting image intensity ratio. Bipolar voltage and local conduction velocity were measured in LA with high-density electroanatomic maps recorded in sinus rhythm and subsequently projected into the LGE-MRI. A semi-automatic, point-by-point correlation was made between LGE-MRI and electroanatomical mapping. Mean bipolar voltage and local velocity progressively decreased from healthy to interstitial fibrosis to scar. There was a significant negative correlation between LGE with voltage (r = -0.39, P < 0.001) and conduction velocity (r = -0.25, P < 0.001). In patients showing dilated atria (LA diameter ≥45 mm) the conduction velocity predictive capacity of LGE-MRI was weaker (r = -0.40 ± 0.09 vs. -0.20 ± 0.13, P = 0.02). CONCLUSIONS: Areas with higher LGE show lower voltage and slower conduction in sinus rhythm. The enhancement intensity correlates with bipolar voltage and conduction velocity in a point-by-point analysis. The performance of LGE-MRI in assessing local velocity might be reduced in patients with dilated atria (LA diameter ≥45).

Arrhythmogenic substrate detection in chronic ischaemic patients undergoing ventricular tachycardia ablation using multidetector cardiac computed tomography: compared evaluation with cardiac magnetic resonance.

AIMS: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits characterizing ischaemic scars, detecting heterogeneous tissue channels (HTCs) which constitute the arrhythmogenic substrate (AS). Late gadolinium enhancement cardiac magnetic resonance also improves the arrhythmia-free survival when used to guide ventricular tachycardia (VT) substrate ablation. However, its availability may be limited. We sought to evaluate the performance of multidetector cardiac computed tomography (MDCT) imaging in identifying HTCs detected by LGE-CMR in ischaemic patients undergoing VT substrate ablation. METHODS AND RESULTS: Thirty ischaemic patients undergoing both LGE-CMR and MDCT before VT substrate ablation were included. Using a dedicated post-processing software, two blinded operators, assigned either to LGE-CMR or MDCT analysis, characterized the presence of CMR and computed tomography (CT) channels, respectively. Cardiac magnetic resonance channels were classified as endocardial (layers < 50%), epicardial (layers ≥ 50%), or transmural. Cardiac magnetic resonance- vs. CT-channel concordance was considered when showing the same orientation and American Heart Association (AHA) segment. Mean age was 69 ± 10 years; 90% were male. Mean left ventricular ejection fraction was 35 ± 10%. All patients had CMR channels (n = 76), whereas only 26/30 (86.7%) had CT channels (n = 91). Global sensitivity (Se) and positive predictive values for detecting CMR channels were 61.8% and 51.6%, respectively. MDCT performance improved in patients with epicardial CMR channels (Se 80.5%) and transmural scars (Se 72.2%). In 4/11 (36%) patients with subendocardial myocardial infarction (MI), MDCT was unable to identify the AS. CONCLUSIONS: Compared to LGE-CMR, myocardial wall thickness assessment using MDCT fails to detect the presence of AS in 36% of patients with subendocardial MI, showing modest sensitivity identifying HTCs but a better performance in patients with transmural scars.

Reduction in new cardiac electronic device implantations in Catalonia during COVID-19.

AIMS: During the COVID-19 pandemic, concern regarding its effect on the management of non-communicable diseases has been raised. However, there are no data on the impact on cardiac implantable electronic devices (CIED) implantation rates. We aimed to determine the impact of SARS-CoV2 on the monthly incidence rates and type of pacemaker (PM) and implantable cardiac defibrillator (ICD) implantations in Catalonia before and after the declaration of the state of alarm in Spain on 14 March 2020. METHODS AND RESULTS: Data on new CIED implantations for 2017-20 were prospectively collected by nine hospitals in Catalonia. A mixed model with random intercepts corrected for time was used to estimate the change in monthly CIED implantations. Compared to the pre-COVID-19 period, an absolute decrease of 56.5% was observed (54.7% in PM and 63.7% in ICD) in CIED implantation rates. Total CIED implantations for 2017-19 and January and February 2020 was 250/month (>195 PM and >55 ICD), decreasing to 207 (161 PM and 46 ICD) in March and 131 (108 PM and 23 ICD) in April 2020. In April 2020, there was a significant fall of 185.25 CIED implantations compared to 2018 [95% confidence interval (CI) 129.6-240.9; P < 0.001] and of 188 CIED compared to 2019 (95% CI 132.3-243.7; P < 0.001). No significant differences in the type of PM or ICD were observed, nor in the indication for primary or secondary prevention. CONCLUSIONS: During the first wave of the COVID-19 pandemic, a substantial decrease in CIED implantations was observed in Catalonia. Our findings call for measures to avoid long-term social impact.

Long-term incidence of upper extremity venous obstruction in implantable cardioverter defibrillator patients.

BACKGROUND: Very little is known about the long-term prevalence of severe venous obstruction and occlusion in patients with transvenous implantable cardioverter-defibrillator leads. The objective of the current investigation was to elucidate the incidence and prevalence and to identify predisposing conditions in an ICD cohort over a long follow-up period. METHODS: Based on a prospective database, we analyzed consecutive patients who received an ICD implantation in our hospital between 06/1988 and 2009 as well as all corresponding follow-up data until 02/2018. Cavographies were used for analysis, and all patients with at least one device replacement and one follow-up cavography were included. RESULTS: Over a mean follow-up period of 94 ± 50 months, severe venous obstruction was found in 147 (33%) of 448 patients. Kaplan-Meier analysis shows a severe obstruction or occlusion in 50% of patients after a period of 14.3 years. The total number of leads (p < .001, HR 2.01, CI 2.000-2.022), an advanced age (p = .004, HR 1.023 per year, CI 1.022-1.024) and the presence of dilated cardiomyopathy (p = .035, HR 1.49, CI 1.47-1.51) were predictive of venous obstruction whereas the presence of anticoagulation was not. CONCLUSION: Severe obstruction of the access veins after ICD implantation occurs frequently and its prevalence shows a nearly linear increase over long-time follow-up. Multiple leads, an advanced age and DCM as underlying disease are associated with an increased risk of venous obstruction while the role of anticoagulation to prevent venous obstruction in ICD patients is unclear.

Automatic Detection of Slow Conducting Channels during Substrate Ablation of Scar-Related Ventricular Arrhythmias.

BACKGROUND: Voltage mapping allows identifying the arrhythmogenic substrate during scar-related ventricular arrhythmia (VA) ablation procedures. Slow conducting channels (SCCs), defined by the presence of electrogram (EGM) signals with delayed components (EGM-DC), are responsible for sustaining VAs and constitute potential ablation targets. However, voltage mapping, as it is currently performed, is time-consuming, requiring a manual analysis of all EGMs to detect SCCs, and its accuracy is limited by electric far-field. We sought to evaluate an algorithm that automatically identifies EGM-DC, classifies mapping points, and creates new voltage maps, named "Slow Conducting Channel Maps" (SCC-Maps). METHODS: Retrospective analysis of electroanatomic maps (EAM) from 20 patients (10 ischemic, 10 with arrhythmogenic right ventricular dysplasia/cardiomyopathy) was performed. EAM voltage maps were acquired during sinus rhythm and used for ablation. Preprocedural contrast-enhanced cardiac magnetic resonance (Ce-CMR) imaging was available for the ischemic population. Three mapping modalities were analysed: (i) EAM voltage maps using standard (EAM standard) or manual (EAM screening) thresholds for defining core and border zones; (ii) SCC-Maps derived from the use of the novel SCC-Mapping algorithm that automatically identify EGM-DCs measuring the voltage of the local component; and (iii) Ce-CMR maps (when available). The ability of each mapping modality in identifying SCCs and their agreement was evaluated. RESULTS: SCC-Maps and EAM screening identified a greater number of SCC entrances than EAM standard (3.45 ± 1.61 and 2.95 ± 2.31, resp., vs. 1.05 ± 1.10; p < 0.01). SCC-Maps and EAM screening highly correlate with Ce-CMR maps in the ischemic population when compared to EAM standard (Lin's correlation = 0.628 and 0.679, resp., vs. 0.212, p < 0.01). CONCLUSION: The SCC-Mapping algorithm allows an operator-independent analysis of EGM signals showing better identification of the arrhythmogenic substrate characteristics when compared to standard voltage EAM.

Ventricular arrhythmia risk is associated with myocardial scar but not with response to cardiac resynchronization therapy.

AIMS: Sudden cardiac death (SCD) risk estimation in patients referred for cardiac resynchronization therapy (CRT) remains a challenge. By CRT-mediated improvement of left ventricular ejection fraction (LVEF), many patients loose indication for primary prevention implantable cardioverter-defibrillator (ICD). Increasing evidence shows the importance of myocardial scar for risk prediction. The aim of this study was to investigate the prognostic impact of myocardial scar depending on the echocardiographic response in patients undergoing CRT. METHODS AND RESULTS: Patients with indication for CRT were prospectively enrolled. Decision about ICD or pacemaker implantation was based on clinical criteria. All patients underwent delayed-enhancement cardiac magnetic resonance imaging. Median follow-up duration was 45 (24-75) months. Primary outcome was a composite of sustained ventricular arrhythmia, appropriate ICD therapy, or SCD. A total of 218 patients with LVEF 25.5 ± 6.6% were analysed [158 (73%) male, 64.9 ± 10.7 years]. Myocardial scar was observed in 73 patients with ischaemic cardiomyopathy (ICM) (95% of ICM patients); in 62 with non-ischaemic cardiomyopathy (45% of these patients); and in all but 1 of 36 (17%) patients who reached the primary outcome. Myocardial scar was the only significant predictor of primary outcome [odds ratio 27.7 (3.8-202.7)], independent of echocardiographic CRT response. A total of 55 (25%) patients died from any cause or received heart transplant. For overall survival, only a combination of the absence of myocardial scar with CRT response was associated with favourable outcome. CONCLUSION: Malignant arrhythmic events and SCD depend on the presence of myocardial scar but not on CRT response. All-cause mortality improved only with the combined absence of myocardial scar and CRT response.

Prediction of premature ventricular complex origin in left vs. right ventricular outflow tract: a novel anatomical imaging approach.

AIMS: Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). METHODS AND RESULTS: Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P < 0.001). Absolute size of all aortic root diameters was associated with LVOT origin. However, after indexing by body surface area, only sinotubular junction diameter maintained a significant association (P = 0.049). Multivariable analysis showed that APVPA was an independent predictor of LVOT origin. Aortopulmonary valvular planar angulation ≥62° reached 94% sensitivity and 83% specificity (area under the curve 0.95) for predicting LVOT origin. CONCLUSIONS: The measurement of APVPA as a marker of chronic LV overload is useful for the prediction of left vs. right ventricular OTVA origin.

Mortality and morbidity reduction after frequent premature ventricular complexes ablation in patients with left ventricular systolic dysfunction.

AIMS: Ablation of frequent premature ventricular complexes (PVCs) improves left ventricular ejection fraction in patients with left ventricular (LV) systolic dysfunction. This study aims to evaluate the long-term hard outcomes and potential prognostic variables in this population. METHODS AND RESULTS: Prospective multicentre study including 101 consecutive patients [56 ± 12 years old, 62 (61%) men] with LV systolic dysfunction and frequent PVCs who underwent PVC ablation before November 2015. The last evaluation performed was considered the long-term follow-up (LTFUP) evaluation. Mean follow-up was 34 ± 16 months (range 24-84 months). Ablation was successful in 95 (94%) patients. There was a significant reduction in the PVC burden from 21 ± 12% at baseline to 3.8 ± 6% at LTFUP, P < 0.001. Left ventricular ejection fraction improved from 32 ± 8% at baseline to 39 ± 12% at LTFUP (P < 0.001) and New York Heart Association class from 2.2 ± 0.6% to 1.3 ± 0.6% (P < 0.001). Brain natriuretic peptide levels decreased from 136 (78-321) to 68 (32-144) pg/mL (P = 0.007). Most of this improvement occurs during the first 6 months after ablation. Persistent abolition of at least 18 points of the baseline PVC burden was independently and inversely associated with the composite endpoint of cardiac mortality, cardiac transplantation, or hospitalization for heart failure during follow-up [hazard ratio 0.18 (0.05-0.66), P = 0.01]. CONCLUSION: In patients with LV systolic dysfunction, ablation of frequent PVCs induces a significant improvement in functional, structural, and neurohormonal status, which persists at LTFUP. A sustained reduction in the baseline PVC burden is associated with a lower risk of cardiac mortality, cardiac transplantation, or hospitalization for heart failure during follow-up.

Elucidation of hidden slow conduction by double ventricular extrastimuli: a method for further arrhythmic substrate identification in ventricular tachycardia ablation procedures.

Aims: Identification of local abnormal electrograms (EGMs) during ventricular tachycardia substrate ablation (VTSA) is challenging when they are hidden within the far-field signal. This study analyses whether the response to a double ventricular extrastimulus during substrate mapping could identify slow conducting areas that are hidden during sinus rhythm. Methods and results: Consecutive patients (n = 37) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration <133 ms were considered as potential hidden slow conduction EGMs (HSC-EGM) if located within/surrounding the scar area. Whenever a potential HSC-EGM was identified, a double ventricular extrastimulus was delivered. If the local potential delayed, it was annotated as HSC-EGM. The incidence of HSC-EGM in core, border-zone, and normal-voltage regions was determined. Ablation was delivered at conducting channel entrances and HSC-EGMs. VT inducibility after VTSA obtained was compared with data from a historic control group. 2417 EGMs were analyzed. 575 (23.7%) qualified as potential HSC-EGM, and 198 of them were tagged as HSC-EGMs. Scars in patients with HSC-EGMs (n = 21, 56.7%) were smaller (35.424.7 vs 67.639.1 cm2; P = 0.006) and more heterogeneous (core/scar area ratio 0.250.2 vs 0.450.19; P = 0.02). 28.8% of HSC-EGMs were located in normal-voltage tissue; 81.3% were targeted for ablation. Patients undergoing VTSA incorporating HSC analysis needed less radiofrequency time (17.411 vs 2310.7 minutes; P = 0.016) and had a lower rate of VT inducibility after VTSA than the historic controls (24.3% vs 50%; P = 0.018). Conclusion: Ventricular tachycardia substrate ablation incorporating HSC analysis allowed further arrhythmic substrate identification (especially in normal-voltage areas) and reduced RF time and VT inducibility after VTSA.

Multielectrode vs. point-by-point mapping for ventricular tachycardia substrate ablation: a randomized study.

Aims: Ventricular tachycardia (VT) substrate ablation is based on detailed electroanatomical maps (EAM). This study analyses whether high-density multielectrode mapping (MEM) is superior to conventional point-by-point mapping (PPM) in guiding VT substrate ablation procedures. Methods and results: This was a randomized controlled study (NCT02083016). Twenty consecutive ischemic patients undergoing VT substrate ablation were randomized to either group A [n = 10; substrate mapping performed first by PPM (Navistar) and secondly by MEM (PentaRay) ablation guided by PPM] or group B [n = 10; substrate mapping performed first by MEM and second by PPM ablation guided by MEM]. Ablation was performed according to the scar-dechanneling technique. Late potential (LP) pairs were defined as a Navistar-LP and a PentaRay-LP located within a three-dimensional distance of ≤ 3 mm. Data obtained from EAM, procedure time, radiofrequency time, and post-ablation VT inducibility were compared between groups. Larger bipolar scar areas were obtained with MEM (55.7±31.7 vs. 50.5±26.6 cm2; P = 0.017). Substrate mapping time was similar with MEM (19.7±7.9 minutes) and PPM (25±9.2 minutes); P = 0.222. No differences were observed in the number of LPs identified within the scar by MEM vs. PPM (73±50 vs. 76±52 LPs per patient, respectively; P = 0.965). A total of 1104 LP pairs were analysed. Using PentaRay, far-field/LP ratio was significantly lower (0.58±0.4 vs. 1.64±1.1; P = 0.01) and radiofrequency time was shorter [median (interquartile range) 12 (7-20) vs. 22 (17-33) minutes; P = 0.023]. No differences were observed in VT inducibility after procedure. Conclusion: MEM with PentaRay catheter provided better discrimination of LPs due to a lower sensitivity for far-field signals. Ablation guided by MEM was associated with a shorter radiofrequency time.

Outcome in patients with left common pulmonary vein after cryoablation with second-generation cryoballoon.

BACKGROUND: Pulmonary vein isolation (PVI) has become a widely accepted therapy in patients suffering from symptomatic atrial fibrillation (AF). HYPOTHESIS: AF-free survival differs in patients with left common pulmonary vein (LCPV) after PVI with second-generation cryoballoon. METHODS: We included patients scheduled for first PVI for paroxysmal or persistent AF. Symptomatic and/or documented arrhythmia episodes (>30 seconds) were defined as AF recurrence, excluding a 3-month blanking period. RESULTS: We observed a LCPV in 37 of 270 consecutive patients (13.7%). Analyses were performed in a 1:1 propensity score matched cohort of 68 patients. During a median follow-up of 77.0 weeks, 37 patients (54.4%) had recurrent AF. The prevalence of LCPV was numerically higher in patients with AF recurrence (62.2% vs 35.5%, P  =  0.051) and Kaplan-Meier analysis showed lower AF-free survival in patients with existence of a LCPV (P  =  0.028). At 1-year follow-up, 70.6% of patients without versus 55.1% of patients with LCPV were free of AF. Multivariate Cox regression analysis revealed presence of a LCPV (hazard ratio [HR]: 2.996), chronic heart failure (HR: 3.423), and mitral regurgitation > I° (HR: 2.571) as predictors of AF recurrence. CONCLUSION: Patients with LCPV had significantly reduced AF-free survival after ablation with the second-generation cryoballoon, despite similar acutely successful PVIs.

Mini-electrodes help identifying hidden slow conduction during ventricular tachycardia substrate ablation.

A 69-year-old male with dilated non-ischemic cardiomyopathy and history of sustained monomorphic VT (SMVT) underwent an unsuccessful VT substrate ablation due to the proximity of the earliest activation site to the conduction system. A second attempt was performed using an ablation catheter with mini-electrodes (ME) and multiple extrastimuli to unveil hidden slow conduction (HSC) sites, allowing the performance of a successful ablation. No SMVT was induced thereafter. ME-obtained electrograms permit to accurately localize areas of HSC sites within ventricular tachycardia (VT) substrates. In our case, this allowed safe ablation during sinus rhythm to eliminate the VT substrate.

Automatic activation mapping and origin identification of idiopathic outflow tract ventricular arrhythmias.

PURPOSE: Activation mapping is used to guide ablation of idiopathic outflow tract ventricular arrhythmias (OTVAs). Isochronal activation maps help to predict the site of origin (SOO): left vs right outflow tract (OT). We evaluate an algorithm for automatic activation mapping based on the onset of the bipolar electrogram (EGM) signal for predicting the SOO and the effective ablation site in OTVAs. METHODS: Eighteen patients undergoing ablation due to idiopathic OTVAs were studied (12 with left ventricle OT origin). Right ventricle activation maps were obtained offline with an automatic algorithm and compared with manual annotation maps obtained during the intervention. Local activation time (LAT) accuracy was assessed, as well as the performance of the 10ms earliest activation site (EAS) isochronal area in predicting the SOO. RESULTS: High correlation was observed between manual and automatic LATs (Spearman's: 0.86 and Lin's: 0.85, both p<0.01). The EAS isochronal area were closely located in both map modalities (5.55 ± 3.56mm) and at a similar distance from the effective ablation site (0.15±2.08mm difference, p=0.859). The 10ms isochronal area longitudinal/perpendicular diameter ratio measured from automatic maps showed slightly superior SOO identification (67% sensitivity, 100% specificity) compared with manual maps (67% sensitivity, 83% specificity). CONCLUSIONS: Automatic activation mapping based on the bipolar EGM onset allows fast, accurate and observer-independent identification of the SOO and characterization of the spreading of the activation wavefront in OTVAs.

Relaxin reduces susceptibility to post-infarct atrial fibrillation in mice due to anti-fibrotic and anti-inflammatory properties.

BACKGROUND: Relaxin-2 (RLX) is a peptide hormone that exerts beneficial anti-fibrotic and anti-inflammatory effects in diverse models of cardiovascular disease. The goal of this study was to determine the effects of RLX treatment on the susceptibility to atrial fibrillation (AF) after myocardial infarction (MI). METHODS: Mice with cryoinfarction of the left anterior ventricular wall were treated for two weeks with either RLX (75 µg/kg/d) or vehicle (sodium acetate) delivered via subcutaneously implanted osmotic minipumps. RESULTS: RLX treatment significantly attenuated the increase in AF-inducibility following cryoinfarction and reduced the mean duration of AF episodes. Furthermore, epicardial mapping of both atria revealed an increase in conduction velocity. In addition to an attenuation of atrial hypertrophy, chronic application of RLX reduced atrial fibrosis, which was linked to a significant reduction in atrial mRNA expression of connective tissue growth factor. Transcript levels of the pro-inflammatory cytokines interleukin-6 and interleukin-1ß were reduced in RLX treated mice, but macrophage infiltration into atrial myocardium was similar in the vehicle and RLX treated groups. CONCLUSION: Treatment with RLX in mice after MI reduces susceptibility to AF due to anti-inflammatory and anti-fibrotic properties. Because to these favorable actions, RLX may become a new therapeutic option in the treatment of AF, even when complicating MI.

Sarcomeric lesions and remodeling proximal to intercalated disks in overload-induced cardiac hypertrophy.

Pressure overload induces cardiac remodeling involving both the contractile machinery and intercalated disks (IDs). Filamin C (FlnC) and Xin actin-binding repeat-containing proteins (XIRPs) are multi-adapters localizing in IDs of higher vertebrates. Knockout of the gene encoding Xin (Xirp1) in mice leads to a mild cardiac phenotype with ID mislocalization. In order to amplify this phenotype, we performed transverse aortic constriction (TAC) on control and Xirp1-deficient mice. TAC induced similar left ventricular hypertrophy in both genotypes, suggesting that the lack of Xin does not lead to higher susceptibility to cardiac overload. However, in both genotypes, FlnC appeared in "streaming" localizations across multiple sarcomeres proximal to the IDs, suggesting a remodeling response. Furthermore, FlnC-positive areas of remodeling, reminiscent of sarcomeric lesions previously described for skeletal muscles (but so far unreported in the heart), were also observed. These adaptations reflect a similarly strong effect of the pressure induced by TAC in both genotypes. However, 2 weeks post-operation TAC-treated knockout hearts had reduced levels of connexin43 and slightly increased incidents of ventricular tachycardia compared to their wild-type (WT) counterparts. Our findings highlight the FlnC-positive sarcomeric lesions and ID-proximal streaming as general remodeling responses in cardiac overload-induced hypertrophy.

A real world wearable cardioverter defibrillator experience - Very high appropriate shock rate in ischemic cardiomyopathy patients at a European single-center.

BACKGROUND: The wearable cardioverter defibrillator (WCD) has emerged as a valuable tool to protect patients with increased risk of sudden cardiac death (SCD). We sought to characterize WCD patients and to analyze predictors of ventricular arrhythmia (VA) occurrence and WCD shock delivery. METHODS AND RESULTS: One hundred fourteen patients with WCD use were included in the study. Indications were mainly ischemic cardiomyopathy (ICM; 31.6%), non-ICM (45.6%) and explantation of implantable cardioverter defibrillator due to device infection (11.4%). We observed sustained VA in 9.6% of the study population and 6.1% received an appropriate shock. VA occurred in 16.7% of ICM, 3.8% of non-ICM and 15.4% of patients with device infection. CONCLUSIONS: Our data demonstrate a very high rate of sustained VA in patients at risk for SCD during WCD use. ICM patients, including those with recent MI, bore the highest risk.

Atrial flutter presenting as broad complex tachycardia in a patient with right sided pneumonectomy.

A 71-year-old man with no history of coronary artery disease presented with palpitations to the emergency department. The 12-lead ECG showed a regular tachycardia with wide QRS complexes (220 bpm) suggestive of ventricular tachycardia. Instead invasive electrophysiological investigation revealed typical atrial flutter as underlying arrhythmia. The altered QRS morphology resulted from displacement of the heart into the right hemithorax due to right-sided pneumonectomy in combination with bundle branch block.

Laserballoon and Cryoballoon Pulmonary Vein Isolation in Persistent and Longstanding Persistent Atrial Fibrillation.

BACKGROUND: Visually guided laserballoon (LB) ablation has recently been introduced for pulmonary vein (PV) isolation (PVI). We analyzed efficacy and safety results of the newly introduced LB ablation technique in patients with persistent and longstanding persistent atrial fibrillation (AF), and compared this with an established standard method using the cryoballoon (CB). METHODS: A total of 35 patients with symptomatic persistent AF underwent LB ablation and were followed-up for 1 year. Results were compared to 35 patients who underwent CB ablation at the same institution and case matched for age, sex, CHA2 DS2 -VASc score, and left atrial volume. RESULTS: Complete isolation of all PVs was achieved in 68.6% in the LB and 97.1% in the CB group (P < 0.01). No significant differences were found for AF-free survival after 12 months in the complete cohort of all patients (LB: 53.3% vs CB: 70.4%; P = n.s.) and after excluding patients without complete PVI (LB: 57.8% vs CB: 72.5%; P = n.s.). LB ablation resulted in longer procedure (158.5 ± 37.9 minutes vs 110.9 ± 26.5 minutes; P < 0.01) and fluoroscopy durations (28.4 ± 11.1 minutes vs 23.5 ± 9.4 minutes; P = 0.04.), and a trend toward more major complications (14.3% vs 2.9%; P = n.s.). Procedure durations and complications declined over time and were level with CB-treated patients when reaching the last quartile of the LB patients. CONCLUSION: PVI in patients with persistent AF using the LB or the CB resulted in comparable success rates. Initial prolongations in procedure and safety parameters as a result of a learning curve effect for the LB have to be considered before starting to use this technique.