Dual-chamber ICD for left bundle branch area pacing: the cardiac resynchronization and arrhythmia sensing via the left bundle (cross-left) pilot study.

BACKGROUND: Left bundle branch area pacing (LBBAP) has emerged as a promising technique to deliver cardiac resynchronization therapy (CRT). However, safety and efficacy of ventricular arrhythmia sensing via the left bundle in implantable cardioverter-defibrillator (ICD) recipients remain unclear. We sought to evaluate the feasibility of a single LBBAP lead connected to a dual-chamber ICD in patients indicated with a CRT-D implantation. METHODS: The CROSS-LEFT pilot study prospectively included 10 consecutive patients with a reduced ejection fraction and a complete left bundle branch block, indicated with a prophylactic CRT-D. A DF-1 lead was implanted at the right ventricular (RV) apex, and an LBBAP lead through the interventricular septum. Ventricular fibrillation was induced at implantation in both conventional (RV) and left bundle branch area sensing configurations. The latter was the final sensing configuration, and patients were implanted with a dual-chamber DF-1 ICD connected to the atrial lead (RA port), the LBBAP lead (RV IS-1 port), and the defibrillation lead (RV DF-1 port), the IS-1 pin being capped. Atrioventricular delay was optimized to ensure fusion between LBBAP and native conduction from the right bundle. Patients were followed during 6 months. RESULTS: No difference between both configurations was observed regarding R-wave sensing in sinus rhythm (p = 0.22), ventricular fibrillation median interval detection (p = 1.00), or total induced episode duration (p = 0.78). LBBAP resulted in a significant reduction of median QRS width from 164 to 126 ms (p = 0.002). Median ventricular sensing significantly improved from 9.7 at implantation to 18.8 mV at 6 months (p = 0.01). Median LVEF also significantly improved from 29 to 44% at 6 months (p = 0.002). CONCLUSION: Ventricular arrhythmia sensing and defibrillation can be performed via a single LBBAP lead connected to a dual-chamber ICD, and is associated with significant electromechanical reverse remodeling. CLINICAL TRIAL REGISTRATION NUMBER: NCT05102227 In patients presenting with left bundle branch block and left ventricular systolic dysfunction, a left bundle branch area pacing lead connected to a DF-1 dual-chamber implantable cardioverter-defibrillator provides safe ventricular arrhythmia sensing and efficient electro-mechanical resynchronization.

Myocardial Fibrosis Predicts Ventricular Arrhythmias and Sudden Death After Cardiac Electronic Device Implantation.

BACKGROUND: Increasing evidence supports a link between myocardial fibrosis (MF) and ventricular arrhythmias. OBJECTIVES: The purpose of this study was to determine whether presence of myocardial fibrosis on visual assessment (MFVA) and gray zone fibrosis (GZF) mass predicts sudden cardiac death (SCD) and ventricular fibrillation/sustained ventricular tachycardia after cardiac implantable electronic device (CIED) implantation. METHODS: In this prospective study, total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, was assessed in relation to the primary endpoint of SCD and the secondary, arrhythmic endpoint of SCD or ventricular arrhythmias after CIED implantation. RESULTS: Among 700 patients (age 68.0 ± 12.0 years), 27 (3.85%) experienced a SCD and 121 (17.3%) met the arrhythmic endpoint over median 6.93 years (IQR: 5.82-9.32 years). MFVA predicted SCD (HR: 26.3; 95% CI: 3.7-3,337; negative predictive value: 100%). In competing risk analyses, MFVA also predicted the arrhythmic endpoint (subdistribution HR: 19.9; 95% CI: 6.4-61.9; negative predictive value: 98.6%). Compared with no MFVA, a GZF mass measured with the 5SD method (GZF5SD) >17 g was associated with highest risk of SCD (HR: 44.6; 95% CI: 6.12-5,685) and the arrhythmic endpoint (subdistribution HR: 30.3; 95% CI: 9.6-95.8). Adding GZF5SD mass to MFVA led to reclassification of 39% for SCD and 50.2% for the arrhythmic endpoint. In contrast, LVEF did not predict either endpoint. CONCLUSIONS: In CIED recipients, MFVA excluded patients at risk of SCD and virtually excluded ventricular arrhythmias. Quantified GZF5SD mass added predictive value in relation to SCD and the arrhythmic endpoint.

Dominant vector changes during early wavebreak/spiral wave (Wiggers stage 1) in ventricular fibrillation: insights from the analysis of 100 electrophysiology studies.

PURPOSE: To describe electrocardiographic vector patterns during early VF transition (Wiggers stage 1). METHODS: In 100 electrophysiology studies with VF induction, the first 3 beats of VF were analyzed in lead I for left/right axis (LA/RA), V1 for left/right bundle (LB/RB), and aVF for superior/inferior axis (SA/IA). Correlation with demographic/clinical factors was performed using regression analyses and mixed effect modeling. RESULTS: VF initiated more likely with LA than RA (P < 0.001) and LB than RB (P = 0.04) suggesting original wavebreak in the right ventricle. The 3-dimensional morphology changed in 69% of VF during the first 3 beats, with predominant increase in RB, suggesting a transition of QRS-originating vector to septum/left ventricle. Conservation of morphology (31%) was favored by initial RB (P = 0.002) and LA morphology (P = 0.01). Initiation of VF with LA vs RA was more likely in African-Americans (P = 0.016) and increasing age (P = 0.032). Ischemic cardiomyopathy favored VF initiation with RB 6.7-fold (P = 0.025), possibly linking LV myocardial scar to initial VF wavebreak location. Male gender and ischemic cardiomyopathy prolonged time-to-loss of predominant vector by 119% (P = 0.002) and 71% (P = 0.017), respectively, suggesting more preserved anatomic/functional reentry. CONCLUSION: The predominant QRS vectors during early Wiggers stage 1 VF are not random and suggest an initial wavebreak more commonly in the right ventricle, followed by a transitional shift to the septum/left ventricle. Ethnicity, male gender, age, and co-morbidities result in directional preservation of initiating VF vectors possibly due to myocardial mass/fibrosis. Findings may allow new treatment/ablation approaches.

Purkinje triggers of ventricular fibrillation in patients with hypertrophic cardiomyopathy.

INTRODUCTION: Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). The origin of VF and the success of catheter ablation to eliminate recurrent episodes in this population are poorly understood. METHODS AND RESULTS: From 2010 to 2014, five patients with HCM (age 21 ± 9 years, three female) underwent invasive electrophysiological studies and ablation at our center after resuscitation from recurrent (9 ± 7) episodes of VF. Ventricular premature beats (VPBs), seen to initiate VF in certain cases, were recorded noninvasively before the ablation procedure. Postprocedural computed tomography (CT) was performed to correlate ablation sites with myocardial hypertrophy in three patients. Outcomes were assessed by clinical follow-up and implantable cardioverter-defibrillator interrogations. VPB triggers were localized invasively to the distal left Purkinje conduction system (left posterior fascicle [2], left anterior fascicle [1], and both fascicles [2]). All targeted VF triggers were successfully eliminated by radiofrequency ablation in the left ventricle. Among patients with postablation CT imaging, 93 ± 12% of ablation sites corresponded to hypertrophied segments. Over 50 ± 38 months, four of five patients were free from primary VF without antiarrhythmic drug therapy. One patient who had 13 episodes of VF before ablation had a single recurrence. CONCLUSION: In our study of patients with HCM and recurrent VF, VF was not initiated from the myocardium but rather from Purkinje arborization. These sources colocalized with the hypertrophic substrate, suggesting electromechanical interaction. Focal ablation at these sites was associated with a marked reduction in VF burden.

Ventricular Fibrillation Arrest and Pulmonary Homograft Rupture During Transcatheter Pulmonary Valve: Successful Rescue by Heart Team.

We describe a 31-year-old woman with pulmonary homograft rupture and ventricular fibrillation arrest complicating a transcatheter pulmonary valve (TPV) procedure. She underwent extracorporeal membrane oxygenation (ECMO) with immediate surgical repair including bioprosthetic pulmonary valve replacement. She had difficulty weaning off ECMO due to hyperacute failure of the valve and ultimately underwent successful hybrid TPV with complete recovery. This case illustrates the importance of the heart team approach during catheter and surgical interventions in adult congenital heart disease.

Ventricular fibrillation in a left ventricular assist device patient: Can the echocardiogram be misleading?

Sustained ventricular tachycardia and ventricular fibrillation (VF) are life-threatening arrhythmias which remain highly prevalent in patients with advanced heart failure. These ventricular arrhythmias may impair the support provided by continuous-flow left ventricular assist devices (CF-LVADs) and lead to frequent hospitalizations, antiarrhythmic medication use, external defibrillations, and need for heart transplantation. We report a case in which a patient with a CF-LVAD and an implantable cardioverter defibrillator at end of life presented with asymptomatic low-flow alarms and was found to have VF of unknown duration. Unique in our case was the presence of apparent organized contractility and rhythmic opening of the mitral valve on echocardiogram despite VF on electrocardiogram.

Long-term outcomes of ablation for ventricular arrhythmias in mitral valve prolapse.

PURPOSE: Prior studies reporting efficacy of radiofrequency catheter ablation for complex ventricular ectopy in mitral valve prolapse (MVP) are limited by selective inclusion of bileaflet MVP, papillary muscle only ablation, or short-term follow-up. We sought to evaluate the long-term incidence of hemodynamically significant ventricular tachycardia (VT) or fibrillation (VF) in patients with MVP after initial ablation. METHODS: We studied consecutive patients with MVP undergoing ablation for complex ventricular ectopy between 2013 and 2017 at our institution. Of 580 patients with MVP, we included 15 (2.6%, 10 women; mean age 50 ± 14 years, 53% bileaflet) with complex ventricular ectopy treated with initial ablation. RESULTS: Over a median follow-up of 3406 (1875-6551) days or 9 years, 5 of 15 (33%) patients developed hemodynamically significant VT/VF after their initial ablation and underwent placement of an implantable cardioverter defibrillator (ICD). Three of 5 also underwent repeat ablations. Sustained VT was inducible prior to index ablation in all 5 who developed VT/VF, compared to none of the 10 patients who did not develop VT/VF after index ablation (p = 0.002). Complex ventricular ectopy at index ablation was multifocal in all 5 patients who underwent repeat intervention versus 4 of 10 patients (40%) who did not (p = 0.04). All 3 patients with subsequent VT/VF who underwent repeat ablation had a new clinically dominant focus of ventricular arrhythmia and 3 of the patients with ICD had appropriate VT/VF therapies. CONCLUSIONS: In the long term, a subset of MVP patients treated with ablation for ventricular arrhythmias, all with multifocal ectopy on initial EP study, develop hemodynamically significant VT/VF. Our findings suggest the progressive nature of ventricular arrhythmias in patients with MVP and multifocal ectopy.

Neurological outcome and modifiable events after out-of-hospital cardiac arrest in patients managed in a tertiary cardiac centre: A ten years register / Desenlaces neurológicos y acontecimientos modificables tras parada cardíaca extrahospitalaria en pacientes tratados en un centro de atención cardíaca terciaria: registro de 10 años

OBJECTIVE: A study was made of the events occurring in the early post-resuscitation phase that may help to improve the outcomes at hospital discharge. DESIGN: A retrospective cohort study (2007-2017) of a prospective Utstein type registry database was carried using multivariate logistic regression analysis. Pre- and post-hospital admission events were investigated. SETTING: A tertiary cardiac centre. PARTICIPANTS: Unconscious victims of out-of-hospital cardiac arrest (OHCA) with documented ventricular tachycardia or fibrillation. MAIN VARIABLES OF INTEREST: Events occurring before and within 72h after intensive care unit (ICU) admission were recorded. The variables were analyzed to determine their impact on hospital survival and poor neurological outcome. One-year follow-up survival was also considered. Results are presented as odds ratio (OR) and 95% confidence interval (95%CI). RESULTS: Of 245 patients admitted to our ICU after OHCA, 152 (62%) were alive and 131 (86.2%) presented good neurological outcomes (cerebral performance categories≤2) at hospital discharge. The one-year follow-up survival rate was 95.9%. Age >70 years (OR 2.0; 95%CI 1.1-4.1), previous myocardial infarction (OR 2.7; 95%CI 1.2-6.1), shock upon hospital admission (OR 2.9; 95%CI 1.3-6.2), time from call to return of spontaneous circulation (ROSC) >25min (OR 3.1; 95%CI 1.6-6.0) and anticonvulsant therapy (OR 18.2; 95%CI 5.5-60) were independent predictors of poor neurological outcome. Immediate admission to the cardiac centre (OR 0.5; 95%CI 0.3-0.9) and lactate clearance reaching plasma levels <2.5mmol/l at 12h (OR 0.4; 95%CI 0.2-0.8) were associated with better outcomes. CONCLUSIONS: Unconscious OHCA patients with documented ventricular tachycardia or fibrillation may benefit from direct admission to a reference cardiac centre. Initial haemodynamic support, urgent coronary angiography and targeted management in the cardiac ICU seem to increase the likelihood of good neurological outcomes

OBJETIVO: Llevar a cabo un estudio de los acontecimientos ocurridos en la fase inmediatamente posterior a la reanimación que puedan ayudar a mejorar los desenlaces en el momento del alta hospitalaria. DISEÑO: Se realizó un estudio retrospectivo (2007-2017) de cohorte de una base de datos de registro de tipo Utstein prospectivo mediante un análisis de regresión logística multivariable. Se investigaron los acontecimientos previos y posteriores al ingreso hospitalario. Ámbito: Un centro de atención cardíaca terciaria. PARTICIPANTES: Víctimas inconscientes de parada cardíaca extrahospitalaria (OHCA) con fibrilación o taquicardia ventricular documentada. VARIABLES PRINCIPALES DE INTERÉS: Se registraron los acontecimientos ocurridos antes y durante las 72h posteriores al ingreso en la unidad de cuidados intensivos (UCI). Se analizaron las variables para determinar su impacto en la supervivencia hospitalaria y los malos desenlaces neurológicos. También se tuvo en consideración la supervivencia en el seguimiento a lo largo de un año. Los resultados se presentan con valores de oportunidad relativa (OR) e intervalo de confianza del 95% (IC del 95%). RESULTADOS: De los 245 pacientes ingresados en nuestra UCI tras una OHCA, 152 (62%) seguían vivos y 131 (86,2%) presentaban unos buenos desenlaces neurológicos (categorías de rendimiento cerebral≤2) en el momento del alta hospitalaria. La tasa de supervivencia en el seguimiento a lo largo de un año fue del 95,9%. La edad>70 años (OR: 2,0; IC del 95%: 1,1-4,1), los antecedentes de infarto de miocardio (OR: 2,7; IC del 95%: 1,2-6,1), el choque en el momento del ingreso hospitalario (OR: 2,9; IC del 95%: 1,3-6,2), el tiempo transcurrido entre la llamada y el regreso a la circulación espontánea (ROSC)>25min (OR: 3,1; IC del 95%: 1,6-6,0) y la administración de tratamiento anticonvulsivo (OR: 18,2; IC del 95%: 5,5-60) fueron factores predictivos independientes de un mal desenlace neurológico. El ingreso inmediato en un centro de cuidados cardíacos (OR: 0,5; IC del 95%: 0,3-0,9) y el hecho de que el aclaramiento de lactato alcanzase unos niveles plasmáticos<2,5mmol/l al cabo de 12h (OR: 0,4; IC del 95%: 0,2-0,8) se asociaron con unos mejores desenlaces. CONCLUSIONES: Los pacientes inconscientes tras OHCA y con fibrilación o taquicardia ventricular documentada podrían beneficiarse del ingreso directo en un centro cardíaco de referencia. El apoyo hemodinámico inicial, la angiografía coronaria urgente y el tratamiento dirigido en la UCI cardíaca parecen aumentar la probabilidad de obtener unos buenos desenlaces neurológicos

Ventricular Fibrillation Storm in Coronavirus 2019.

Cardiac arrhythmia is a known manifestation of novel coronavirus 2019 (COVID-19) infection. Herein, we describe the clinical course of an otherwise healthy patient who experienced persistent ventricular tachycardia and fibrillation which is believed to be directly related to inflammation, as opposed to acute myocardial injury or medications that can prolong the QT interval.

Assessment of right ventricular sympathetic dysfunction in patients with arrhythmogenic right ventricular cardiomyopathy: An 123I-metaiodobenzylguanidine SPECT/CT study.

PURPOSE: The purpose of the study was to evaluate a novel approach for the quantification of right ventricular sympathetic dysfunction in patients diagnosed with ARVC/D through state-of-the-art functional SPECT/CT hybrid imaging. METHODS: Sympathetic innervation of the heart was assessed using 123I-MIBG-SPECT/CT in 17 patients diagnosed with ARVC according to the modified task force criteria, and in 10 patients diagnosed with idiopathic ventricular fibrillation (IVF). The 123I-MIBG-uptake in the left (LV) and right ventricle (RV) was evaluated separately based on anatomic information derived from the CT scan, and compared to the uptake in the mediastinum (M). RESULTS: There was a significant difference in the LV/M ratio between the ARVC/D and the IVF groups (3.2 ± 0.5 vs. 3.9 ± 0.8, P = 0.014), with a cut-off value of 3.41 (77% sensitivity, 80% specificity, AUC 0.78). There was a highly significant difference in the mean RV/M ratios between both groups (1.6 ± 0.3 vs. 2.0 ± 0.2, P = 0.001), with optimal cut-off for discrimination at 1.86 (88% sensitivity, 90% specificity, AUC 0.93). CONCLUSION: Employing state-of-the-art functional SPECT/CT hybrid imaging, we could reliably assess and quantify right and left ventricular sympathetic innervation. The RV/M ratio was significantly lower in patients diagnosed with ARVC/D and provided sensitive and specific discrimination between patients with ARVC/D and IVF patients.

Generation of ECG signals from a reaction-diffusion model spatially discretized.

We propose a model to generate electrocardiogram signals based on a discretized reaction-diffusion system to produce a set of three nonlinear oscillators that simulate the main pacemakers in the heart. The model reproduces electrocardiograms from healthy hearts and from patients suffering various well-known rhythm disorders. In particular, it is shown that under ventricular fibrillation, the electrocardiogram signal is chaotic and the transition from sinus rhythm to chaos is consistent with the Ruelle-Takens-Newhouse route to chaos, as experimental studies indicate. The proposed model constitutes a useful tool for research, medical education, and clinical testing purposes. An electronic device based on the model was built for these purposes.