Baseline Rhythm Research Articles

Benefits of upgrading right ventricular to biventricular pacing in heart failure patients with atrial fibrillation.

Recommendations on cardiac resynchronization therapy (CRT) in patients with atrial fibrillation or flutter (AF) are based on less robust evidence than those in sinus rhythm (SR). We aimed to assess the efficacy of CRT upgrade in the BUDAPEST-CRT Upgrade trial population by their baseline rhythm. Heart failure patients with reduced ejection fraction (HFrEF) and previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and ≥20% right ventricular (RV) pacing burden were randomized to CRT with defibrillator (CRT-D) upgrade (n = 215) or ICD (n = 145). Primary [HF hospitalization (HFH), all-cause mortality, or <15% reduction of left ventricular end-systolic volume] and secondary outcomes were investigated. At enrolment, 131 (36%) patients had AF, who had an increased risk for HFH as compared with those with SR [adjusted hazard ratio (aHR) 2.99; 95% confidence interval (CI) 1.26-7.13; P = 0.013]. The effect of CRT-D upgrade was similar in patients with AF as in those with SR [AF adjusted odds ratio (aOR) 0.06; 95% CI 0.02-0.17; P < 0.001; SR aOR 0.13; 95% CI 0.07-0.27; P < 0.001; interaction P = 0.29] during the mean follow-up time of 12.4 months. Also, it decreased the risk of HFH or all-cause mortality (aHR 0.33; 95% CI 0.16-0.70; P = 0.003; interaction P = 0.17) and improved the echocardiographic response (left ventricular end-diastolic volume difference -49.21 mL; 95% CI -69.10 to -29.32; P < 0.001; interaction P = 0.21). In HFrEF patients with AF and PM/ICD with high RV pacing burden, CRT-D upgrade decreased the risk of HFH and improved reverse remodelling when compared with ICD, similar to that seen in patients in SR.

Appropriate Selection of Substrate Ablation for Persistent Atrial Fibrillation Using Intraprocedural Assessment.

It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation plus pulmonary vein isolation (PVI). This study aimed to identify PerAF patients who required substrate ablation using intraprocedural assessment of the baseline rhythm and the origin of atrial fibrillation (AF) triggers.Methods and Results: This was a post hoc subanalysis using extended data of the EARNEST-PVI trial, a prospective multicenter randomized trial comparing PVI-alone and PVI-plus (i.e., PVI with added catheter ablation) arms. We divided 492 patients into 4 groups according to baseline rhythm and the location of AF triggers before PVI: Group A (n=22), sinus rhythm with pulmonary vein (PV)-specific AF triggers (defined as reproducible AF initiation from PVs only); Group B (n=211), AF with PV-specific AF triggers; Group C (n=94), sinus rhythm with no PV-specific AF trigger; Group D (n=165), AF with no PV-specific AF trigger. Among the 4 groups, only in Group D (AF at baseline and no PV-specific AF triggers) was arrhythmia-free survival significantly lower in the PVI-alone than PVI-plus arm (P=0.032; hazard ratio 1.68; 95% confidence interval 1.04-2.70). Patients with sinus rhythm or PV-specific AF triggers did not receive any benefit from substrate ablation, whereas patients with AF and no PV-specific AF trigger benefited from substrate ablation.

Targeting Wavefront Discontinuity Lines for Scar-Related Ventricular Tachycardia Ablation: A Novel Functional Substrate Ablation Approach

BackgroundThe boundaries of critical isthmuses for re-entrant ventricular tachycardia (VT) are formed by wavefront discontinuities (fixed lines of block, slow propagation, and rotational propagation) seen during baseline rhythm. It is unknown whether wavefront discontinuities can be automatically identified and targeted for ablation using electroanatomic mapping systems. ObjectivesThe purpose of this study was to assess the electrophysiologic characteristics of automatically projected wavefront discontinuity lines (WADLs) and outcomes of an ablation strategy targeting WADLs in a mixed cohort of VT patients. MethodsLate activation substrate maps were analyzed from 1 or more baseline rhythm wavefronts. WADLs were identified using the Carto Extended Early Meets Late module. Number, total length, and distance to critical VT sites were measured. VT recurrence and VT-free survival were followed. ResultsIn total, 49 patients underwent 52 ablations with 71 unique substrate maps analyzed (18.8% epicardial; 62.0% right ventricular paced, 28.2% sinus rhythm, 9.9% left ventricular paced). A total of 28 VT critical sites were identified in 24 patients. WADLs were present in 49 of 71 (69.0%) maps. WADLs were present regardless of cardiomyopathy etiology, mapping wavefront, or surface. At a WADL threshold of 30%, 73.9% of critical VT sites were in close proximity (≤15 mm) to a WADL. VT-free survival was 62% at 1 year, with a competing risk model estimating a 1-year risk of VT recurrence of 23%. ConclusionsWADLs can be automatically projected in a majority of patients in a mixed cohort of cardiomyopathy etiology, mapped wavefronts, and myocardial surfaces mapped. Targeting WADLs results in low rate of VT recurrence at 1 year.

Effect of implantable cardioverter defibrillator intracardiac electrogram morphology changes on hospitalization and life quality

Abstract Background Implantable Cardioverter Defibrillators (ICD) are standard therapy for patients at risk of life-threatening ventricular tachyarrhythmias. ICDs use morphology discrimination to compare ventricular electrogram during tachycardia with reference template during baseline rhythm. Baseline morphology match score (MMS) changes may predict arrhythmic events, but usefulness as a parameter for heart failure (HF) is still unknown. Methods The prospective single-center study included consecutive 88 patients undergoing device control at cardiology department from July 2022 to May 2023. Inclusion criteria were patients implanted with ICD or CRT for at least 3 months; the exclusion criteria were defined as communication barriers (n=1), depleted device battery during checks (n=1), total AV block (n=3), and auto-template activation (n=4). The data were analysed for changes in the baseline (MMS) relationship with demographic, clinical characteristics, quality of life (QOL), and hospitalisation with HF. Results We analyzed 79 patients with a mean age 64,9 13,6 and an average MMS of 98 1,8 morphology. During follow-up there were 12 (15%) patients hospitalized due to HF. ROC curve analysis showed that a MMS ≤ 97% had 73% sensitivity and 59% specificity for hospitalization (p: 0,033 Area 0.695). No significant differences were observed in demographics between the two groups. Although there was no significant difference in EF and BNP levels, patients with MMS &amp;lt;97% had lower QOL scores and more hospitalizations for heart failure (HF). Conclusion EGM baseline MMS changes in ICD were associated with hospitalization for HF and QOL, apart from arrhythmia detection indications. It may be a follow-up parameter for HF, in addition to the current device algorithms.Graphical AbstractTable 1

Optimising electrical performance of leadless cardiac resynchronisation therapy and leadless LV septal pacing

Abstract Introduction Leadless left ventricular (LV) endocardial pacing with the WiSE-CRT System is an emerging form of cardiac resynchronisation therapy (CRT). The system was designed to provide lateral wall LV pacing (LVP) via an endocardial receiver electrode in response to detection of a right ventricular pacing (RVP) stimulus from a co-implanted device, thereby delivering near-simultaneous biventricular pacing (BiVP). However, it is unclear whether BiVP generates the optimal electrical performance in this system, particularly in the context of leadless LV septal pacing, a novel use for leadless CRT. Aim We aimed to characterise the acute performance of leadless CRT at different pacing modalities using electrocardiographic imaging (ECGi). Methods Patients with the leadless CRT underwent an acute ECGi study. The following pacing modalities were tested: RVP; BiVP; LVP; and LVP with an electrically optimised atrioventricular delay (LV-OPT) in patients with sinus rhythm (SR). Reconstructed epicardial electrograms (Figure 1) were used to calculate BiV activation time (BIVAT-90), LV activation time (LVAT-90), RV activation time (RVAT-90), LV dyssynchrony index (LVDI), and BiV dyssynchrony index (BIVDI). For each metric, the improvement compared to baseline rhythm was calculated, and the optimal pacing modality (OPM) in each patient was determined. Results Ten patients were studied, 5 receiving septal LVP, and 5 receiving lateral LVP. The underlying rhythm in 4 patients was SR with left bundle branch block (LBBB), and atrial fibrillation (AF) with complete heart block (CHB) in the remaining 6. BiVP generated a 23.7% improvement in BiVAT-90 compared to baseline (p=0.002). An individualised OPM resulted in a 43.3% BiVAT-90 improvement compared to baseline (p=0.0001), thus a 19.6% improvement compared to BiVP (p=0.02, Figure 2A). Using an OPM, BiVAT-90 was significantly improved in both patients with lateral (43.3%, p=0.0001) and septal LVP (42.4%, p=0.009). The BiVAT-90 OPM varied between patients (Figure 2B). BiVP was the OPM in 4/10 patients, all of whom had AF with CHB. BiVP was the OPM in 1/5 patients receiving LV septal pacing, with LVP or LV-OPT performing best in the remaining 4. In 3/4 patients in SR, LV-OPT was the OPM. Choosing the OPM increased performance primarily through significant improvements in RVAT-90 compared to BiVP (36.5% versus -8.2%, p =0.002). Conclusion Leadless CRT, both with lateral and septal LVP, significantly reduces electrical activation times and improves electrical dyssynchrony. Individualised selection of the OPM may be required with leadless CRT to accommodate for varying conduction disease phenotypes and implant locations.

Comparison of different rhythmic auditory stimuli on prefrontal cortex cortical activation during upper limb movement in patients with Parkinson's disease: a functional near-infrared spectroscopy study.

A large number of literatures show that rhythmic auditory stimulation (RAS) can effectively improve Parkinson's disease (PD) patients' gait speed, frequency and speed. Its application and curative effect on upper limb motor function is relatively few. By studying the immediate effect of RAS with different rhythms on the prefrontal cortex (PFC) blood oxygen response during upper limb movement in PD patients, this study discusses the potential neurophysiological mechanism of RAS on upper limb movement in PD patients, which is expected to provide guidance for patients with upper limb dysfunction such as Parkinson's disease. In this study, 31 PD patients with upper limb static tremors were recruited to complete the nail board task on the healthy upper limb under the baseline rhythm, slow rhythm and fast rhythm provided by the therapist. At the same time, fNIRS was used to observe the blood oxygen response of PFC. There was no significant main effect onsidein all brain regions (p > 0.05), and there was no interaction between rhythm and side (p > 0.05); Except lPFC, the main effect of rhythm in other brain regions was significant (p < 0.05), and ΔHbO increased with the change of rhythm. Paired analysis showed that there were significant differences in ΔHbO between slow rhythm and baseline rhythm, between fast rhythm and baseline rhythm, and between slow rhythm and fast rhythm (p < 0.05); The ΔHbO of rPFC, lDLPFC and rDLPFC were significantly different between slow rhythm and fast rhythm (p < 0.05); there were significant differences in the ΔHbO of BA8 between slow rhythm and baseline rhythm, and between slow rhythm and fast rhythm (p < 0.05). RAS may be a useful upper limb rehabilitation strategy for PD patients with upper limb dysfunction. At the same time, RAS with different rhythms also have different responses to PFC blood oxygen during upper limb movement in PD patients, so that we can design interventions for this kind of cortical mechanism. Identifying the neurophysiological mechanism of RAS on upper limb movement in PD patients may help clinicians customize rehabilitation methods for patients according to clues, so as to highly personalize upper limb training and optimize its effect.

Acute symptomatic epileptic seizures. A clinical-electroencephalographic etiological description and prognosis of an oncopediatric series

To determine clinical, electroencephalographic, therapeutic and evolutive characteristics of a series of oncopediatric patients with acute symptomatic seizures. We performed a retrospective and prospective descriptive analysis of clinical records of oncopediatric children evaluated by neurology at the comprehensive outpatient Center for Hemato-Oncological Patients during 2017-2021. We included children aged one month to 17 years with intracranial and extracranial tumors who presented with acute symptomatic seizure (ASC). We defined acute symptomatic seizure according to the 2010 International League Against Epilepsy. We classified seizures according to 2017 International League Against Epilepsy classification. We excluded any patient with a diagnosis of previous epilepsy and non-epileptic paroxysmal episodes. We analyzed 44 cases with a median of 4 years (range: 1 month-17 years) and mean of 5.75 months (range: 1 month-11 months) and 8.33 years (2-17 years). The main etiologies were neurotoxicity and post-surgical context. Four patients presented dysnatremias and two associated with endocranial hypertension. Forty-one electroencephalograms were performed with intercritical results with abnormalities in the baseline rhythm, but without foci or paroxysms. There were no critical recordings. Focal seizures were 25 (56.8%) and generalized seizures 19 (43.18%). Levetiracetam was the most commonly used drug for acute management. Our cohort shows that ASC, in this population, do not show considerable differences between focal motor and generalized seizures and occur mostly in neurotoxic and post-surgical contexts. Dysnatremias and endocranial hypertension associated with ASC were also recorded. Postcrisis electroencephalograms were without foci or paroxysms and good seizure evolution.

Transcoronary mapping with an over-the-wire multielectrode catheter in scar-related ventricular tachycardia patients.

The usefulness of coronary venous system mapping has been reported for assessing intramural and epicardial substrates in patients with scar-related ventricular tachycardia (VT). However, there has been little data on mapping from coronary arteries. We investigated the safety and utility of mapping from coronary arteries with a novel over-the-wire multielectrode catheter in scar-related VT patients. Ten consecutive scar-related VT patients with non-ischaemic cardiomyopathy who underwent mapping from a coronary artery were analysed. Six patients underwent simultaneous coronary venous mapping. High-density maps were created by combining the left ventricular endocardium and coronary vessels. Substrate maps were created during the baseline rhythm with 2438 points (IQR 2136-3490 points), including 329 (IQR 59-508 points) in coronary arteries. Abnormal bipolar electrograms were successfully recorded within coronary arteries close to the endocardial substrate in seven patients. During VT, isthmus components were recorded within the coronary vessels in three patients with no discernible isthmus components on endocardial mapping. The ablation terminated the VT from an endocardial site opposite the earliest site in the coronary arteries in five patients. The transcoronary mapping with an over-the-wire multielectrode catheter can safely record abnormal bipolar electrograms within coronary arteries. Additional mapping data from the coronary vessels have the potential to assess three-dimensional ventricular substrates and circuit structures in scar-related VT patients.

Appropriate selection of substrate ablation in patients with persistent atrial fibrillation using an on-day assessment of baseline rhythm and trigger origin

Abstract Background It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation. Purpose To identify the appropriate patients with PerAF who required an additional substrate ablation plus pulmonary vein isolation (PVI) using an on-day assessment of the baseline rhythm during the procedure and origin of the AF trigger. Methods This study was a post hoc sub-analysis of the EARNEST-PVI (Effect of Extensive Ablation on Recurrence in Patients with Persistent AF Treated with Pulmonary Vein Isolation) trial, which was a prospective, multicenter, randomized, open-label trial, comparing the PVI-alone and PVI-plus arms. The patients were divided into 2 groups according to the baseline rhythm and origin of the AF trigger. AF trigger was induced before catheter ablation using isoproterenol infusion (maximum dose of 0.4 μg/kg/min). Proven pulmonary vein (PV) triggers were defined as reproducible AF triggers from only the PVs. Group A consisted of patients with sinus rhythm at the baseline or proven PV triggers. Proven PV triggers were defined as reproducible AF triggers from only the PVs. Group B consisted of the remaining patients, who were AF at baseline and had non-proven PV triggers. The arrhythmia-free survival after a 3-month blanking period was assessed. Results Among the group A patients (n=327, Figure 1), the arrhythmia-free survival did not significantly differ between the PVI-alone and PVI-plus arms (p=0.276, HR 1.22, 95% CI: 0.85-1.76) (Figure 2, upper panel). Among the group B patients (n-166, Figure 1), who had AF at baseline and non-PV triggers, the arrhythmia-free survival was significantly lower in the PVI-alone than PVI-plus arm (p=0.032, HR 1.68, 95% CI: 1.04-2.70) (Figure 2 lower panel). Conclusion The on-day assessment of the baseline rhythm and trigger origin could distinguish patients who benefited from an additional ablation plus PVI. With an additional ablation plus PVI, the patients with sinus rhythm at baseline or who had proven PV triggers did not receive any benefit, whereas those with AF at baseline and no proven PV triggers received a benefit.Figure 1Figure 2

Abstract 13576: Long-Term Serial Changes in Echocardiographic Parameters in Patients With Heart Failure With Preserved Ejection Fraction After Catheter Ablation for Atrial Fibrillation

Background: Heart failure with preserved ejection fraction (HFpEF) is frequently complicated by atrial fibrillation (AF). Catheter ablation for AF is an effective method for restoring and maintaining sinus rhythm (SR). However, there is limited data on the serial changes in echocardiographic parameters in patients with HFpEF after ablation. Hypothesis: The serial changes in echocardiographic parameters after ablation for AF depend not only on baseline rhythm but also on the presence of HFpEF. Methods: A retrospectively review was conducted on 1109 out of 2123 patients who had serial echocardiographic data available before the ablation procedure and at 1-year, 2-year, and 3-year follow-ups. The changes in echocardiographic parameters were assessed using repeated measures ANOVA with a Greenhouse-Geisser correction and Bonferroni tests in four groups, which were divided according to baseline rhythm and HFpEF. HFpEF was defined as an HFA-PEFF score ≥ 5 or 2-4 and left atrial pressure ≥ 15 mmHg at the time of catheter ablation. Results: The prevalence of HFpEF was 51.9%, and paroxysmal AF was present in 65%. Left atrial volume index (LAVI) was larger at baseline in patients with AF and significant decreased after ablation in all groups. The trend of left atrial emptying fraction (LAEF) increased in patients with baseline AF until 1year later, while in patients with baseline SR and HFpEF, LAEF gradually declined even after catheter ablation. The trend of left ventricular ejection fraction increased in patients with baseline AF. The trend of mean E/E’ mildly increased after ablation in all groups. There were significant differences between HFpEF and non-HFpEF. (Figure) Conclusions: Catheter ablation was associated with changes of LA size, function and left ventricular function. Baseline rhythm and the presence of HFpEF play a complex role in the course of cardiac function after ablation.

Abstract 15885: A Masquerading Early Beat Induces Ventricular Fibrillation

Clinical Case: A 51 year old male with a history of hypertension, G6PD deficiency, thrombotic thrombocytopenic purpura, prior stroke, and morbid obesity presented with resuscitated out of hospital VF arrest. Electrolytes and ECG were normal. During his admission, the patient had two VF events that were induced by what appeared to be a short coupled right bundle branch block (RBBB) morphology PVC. He was brought to the electrophysiology lab for PVC ablation and ICD implantation. Baseline rhythm was sinus with what appeared to be both RBBB morphology PVCs and junctional extrasystoles. With both extrasystoles, the His potential preceded the QRS by 50 ms, and atrial activation in the His catheter and coronary sinus catheter was also earlier than the QRS. Activation mapping of the right bundle showed later activation than the His potential. This was all consistent with junctional premature complexes (JPC) with frequent RBBB aberrancy rather than fascicular PVCs. Slow pathway modification was performed to attempt to ablate the JPCs. After multiple ablations along the tricuspid annulus and back to the coronary sinus os that triggered slow junctional beats, the patient’s JPC burden was significantly reduced. An ICD was also implanted. The patient was discharged on flecainide. At 4 month follow up he had not had recurrence. Discussion: Early coupled PVCs are a well-known cause of ventricular fibrillation, but JPCs inducing VF have not been described previously. Placement of a coronary sinus and His catheter helped identify early that this was not simply a fascicular PVC. This case demonstrates the importance of keeping a broad differential diagnosis when starting any EP study. Ablating the slow pathway area can be effective to treat JPCs while preserving native AV conduction as demonstrated in this case.

Prognostic implications of baseline rhythm during catheter ablation for atrial tachycardia.

Atrial tachycardias (AT) occurring in patients after previous atrial fibrillation (AF) ablation are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The purpose of this study was to assess procedural and clinical outcome depending on baseline rhythm at the beginning of AT ablation. A total of 380 patients (69 (61-75) years, 56.6% male) who underwent catheter ablation for consecutive AT after previous AF ablation were studied. At the beginning of the procedure, 140 patients (36.8%) presented in sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF. Patients in SR or with AT underwent shorter procedures (173 (132-213) minutes vs. 161 (120-203) minutes vs. 226 (154-249) minutes; p = 0.002) with more frequent termination to SR (87.9% vs. 81.3% vs. 56.3%; p < 0.001) than patients with AF. Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (96.4% vs. 97.1% vs. 87.5%; p = 0.033). During a follow-up of 290 (181-680) days, patients in baseline SR experienced arrhythmia recurrences less often (36.4% vs. 49.5% vs. 68.8%; p = 0.002) than patients with AT or AF. Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favorable mid-term success rate.

Catheter-induced right bundle branch block: Practical implications for the cardiac electrophysiologist.

The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by "bumping" during right-heart catheterization. In the era of cardiac electrophysiology, catheter-induced RBB block (CI-RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre-existing RBBB, the transient nature of CI-RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI-RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self-limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI-RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His-Purkinje-System, such as fasciculo-ventricular pathways, bundle branch reentry, and right-Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI-RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates.

Identification of Human Ventricular Tachycardia Demarcated by Fixed Lines of Conduction Block in a 3-Dimensional Hyperboloid Circuit.

The circuit boundaries for reentrant ventricular tachycardia (VT) have been historically conceptualized within a 2-dimensional (2D) construct, with their fixed or functional nature unresolved. This study aimed to examine the correlation between localized lines of conduction block (LOBs) evident during baseline rhythm with lateral isthmus boundaries that 3-dimensionally constrain the VT isthmus as a hyperboloid structure. A total of 175 VT activation maps were correlated with isochronal late activation maps during baseline rhythm in 106 patients who underwent catheter ablation for scar-related VT from 3 centers (42% nonischemic cardiomyopathy). An overt LOB was defined by a deceleration zone with split potentials (≥20 ms isoelectric segment) during baseline rhythm. A novel application of pacing within deceleration zone (≥600 ms) was implemented to unmask a concealed LOB not evident during baseline rhythm. LOBs identified during baseline rhythm or pacing were correlated with isthmus boundaries during VT. Among 202 deceleration zones analyzed during baseline rhythm, an overt LOB was evident in 47%. When differential pacing was performed in 38 deceleration zones without overt LOBs, an underlying concealed LOB was exposed in 84%. In 152 VT activation maps (2D=53, 3-dimensional [3D]=99), 69% of lateral boundaries colocalized with an LOB in 2D activation patterns, and the depth boundary during 3D VT colocalized with an LOB in 79%. In VT circuits with isthmus regions that colocalized with a U-shaped LOB (n=28), the boundary invariably served as both lateral boundaries in 2D and 3D. Overall, 74% of isthmus boundaries were identifiable as fixed LOBs during baseline rhythm or differential pacing. The majority of VT circuit boundaries can be identified as fixed LOBs from intrinsic or paced activation during sinus rhythm. Analysis of activation while pacing within the scar substrate is a novel technique that may unmask concealed LOBs, previously interpreted to be functional in nature. An LOB from the perspective of a myocardial surface is frequently associated with intramural conduction, supporting the existence of a 3D hyperboloid VT circuit structure. Catheter ablation may be simplified to targeting both sides around an identified LOB during sinus rhythm.

The outcomes of cardiopulmonary resuscitation and their predictors during the coronavirus 2019 pandemic in Iran

BackgroundCoronavirus disease 2019 (COVID-19) can negatively affect different healthcare-related outcomes. Nonetheless, there is limited information about its effects on different healthcare-related outcomes. This study aimed at evaluating the outcomes of cardiopulmonary resuscitation (CPR) and their predictors during the COVID-19 pandemic in Iran.MethodsThis cross-sectional study was conducted on 1253 patients who had undergone CPR in the emergency wards of teaching hospitals in the west of Iran from the beginning of the first wave to the end of the third epidemic wave of COVID-19 in Iran, between February 20, 2020, and January 20, 2021. Data were collected using the National CPR Documentation Forms developed based on the Utstein Style and routinely used for all patients with cardiac arrest (CA). The SPSS (v. 20.0) program was used to analyze the data through the Chi-square, Fisher’s exact, and Mann-Whitney U tests and logistic regression analysis.ResultsParticipants’ age mean was 64.62 ± 17.54 years. Age mean among participants with COVID-19 was eight years more than other participants. Most participants were male (64.09%) and had at least one underlying disease (64.99%). The total rates of the return of spontaneous circulation (ROSC) and CPR–discharge survival were respectively 15.3% and 3.8% among all participants, 20.25% and 5.17% among participants without COVID-19, and 8.96% and 2.04% among participants with COVID-19. The significant predictors of ROSC were age, affliction by COVID-19, affliction by underlying diseases, baseline rhythm, delay in epinephrine administration, and epinephrine administration time interval, while the significant predictors of CPR–discharge survival were age and baseline rhythm.ConclusionsThe total rates of ROSC and CPR–discharge survival were respectively 15.3% and 3.8% among all participants. The rates of ROSC and CPR to discharge survival among patients without COVID-19 are respectively 2.26 and 2.53 times more than the rates among patients with COVID-19.

Uncovering personalized glucose responses and circadian rhythms from multiple wearable biosensors with Bayesian dynamical modeling

Wearable biosensors and smartphone applications can measure physiological variables over multiple days in free-living conditions. We measure food and drink ingestion, glucose dynamics, physical activity, heart rate (HR), and heart rate variability (HRV) in 25 healthy participants over 14days. We develop a Bayesian inference framework to learn personal parameters that quantify circadian rhythms and physiological responses to external stressors. Modeling the effects of ingestion events on glucose levels reveals that slower glucose decay kinetics elicit larger postprandial glucose spikes, and we uncover a circadian baseline rhythm for glucose with high amplitudes in some individuals. Physical activity and circadian rhythms explain as much as 40%-65% of the HR variance, whereas the variance explained for HRV is more heterogeneous across individuals. A more complex model incorporating activity, HR, and HRV explains up to 15% of additional glucose variability, highlighting the relevance of integrating multiple biosensors to better predict glucose dynamics.

Left bundle branch area pacing reduces epicardial dispersion of repolarization compared with biventricular cardiac resynchronization therapy

Biventricular endocardial pacing (BiV-endo) and left bundle branch area pacing (LBBAP) are novel methods of delivering cardiac resynchronization therapy. These techniques are associated with improved activation times and acute hemodynamic response compared with conventional biventricular epicardial pacing (BiV-epi); however, the effects on repolarization and arrhythmic risk are unknown. The purpose of this study was to compare the effects of temporary BiV-epi, BiV-endo, and LBBAP on epicardial left ventricular (LV) repolarization using electrocardiographic imaging (ECGi). Eleven patients indicated for cardiac resynchronization therapy underwent a temporary pacing protocol with ECGi. BiV-endo was delivered via endocardial stimulation of the LV lateral wall. LBBAP was delivered by pacing the LV septum. Epicardial LV repolarization time (LVRT-95; time taken for 95% of the LV to repolarize), LV RT dispersion, mean LV activation recovery interval (ARI), LV ARI dispersion, and RT gradients were calculated. The protocol was completed in 10 patients. During LBBAP, there were significant reductions in LVRT-95 (94.9 ± 17.4 ms vs 125.0 ± 29.4 ms; P=.03) and LV RT dispersion (29.4 ± 6.3 ms vs 40.8 ± 11.4 ms; P = .015) compared with BiV-epi. In contrast, there were no significant differences between baseline, BiV-epi, or BiV-endo. There was a nonsignificant reduction in mean RT gradients between LBBAP and baseline rhythm (0.74 ± 0.22 ms/mm vs 1.01 ± 0.31 ms/mm; P = .07). There were no significant differences in mean LV ARI or LV ARI dispersion between groups. Temporary LBBAP reduces epicardial dispersion of repolarization compared with conventional BiV-epi. Further study is required to determine whether these repolarization changes on ECGi translate into a reduced risk of ventricular arrhythmia in clinical practice.

Correlation Between Functional Substrate Mapping and Cardiac Computed Tomography–Derived Wall Thinning for Ventricular Tachycardia Ablation

BackgroundFunctional substrate mapping during baseline rhythm can identify arrhythmogenic tissue during ventricular tachycardia (VT) ablation. Wall thinning and wall thickness channels (WTCs) derived from computed tomography angiography have been shown to correlate with low voltage and VT isthmuses. The correlation between functional substrate mapping, wall thinning, and WTCs in patients with infarct- or non–infarct-related cardiomyopathies (ICM and NICM, respectively) has not been previously described. ObjectivesThe purpose of this study was to correlate cardiac CTA-derived myocardial wall thinning with functional VT substrate mapping using isochronal late activation mapping. MethodsIn 34 patients with ICM or NICM undergoing VT ablation who had a preprocedure computed tomography angiography, myocardial wall thinning was segmented in layers of 1 to 5 mm. Areas of wall thinning and WTCs were then spatially correlated with deceleration zones (DZs) from registered left ventricular endocardial isochronal late activation maps. ResultsIn 21 ICM patients and 13 NICM patients, ICM patients had greater surfaces areas of wall thinning (P < 0.001). In ICM patients, 94.1% of primary DZs were located on areas of wall thinning, compared to 20% of DZs in NICM patients overall but 50% if there was any wall thinning present. Fifty-nine percent of DZs in ICM patients and 56% of DZs in NICM patients were located near WTCs. The positive predictive value for WTC in localizing DZs was 22.5% and 37.8% in ICM and NICM patients, respectively. ConclusionsWall thinning is highly sensitive for functional substrate in ICM patients. WTCs had modest sensitivity for functional substrate but low positive predictive value for identifying DZs in ICM and NICM patients. These findings suggest that wall thinning may facilitate more efficient mapping in ICM patients, but WTCs are insufficient to localize wavefront discontinuities.

Baseline rhythm during catheter ablation for atrial tachycardia predicts procedural and clinical outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial tachycardias (AT) occurring after previous ablation in patients with a history of atrial fibrillation (AF) are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The prognostic implications of baseline rhythm at the beginning of AT ablation are unknown. Purpose The aim of this study was to assess procedural and clinical outcome depending on baseline rhythm during AT ablation. Methods A total of 380 patients with a history of AF who underwent catheter ablation for consecutive AT after previous ablation were analysed. Results In our study population (69 (61–75) years, 56.6% male), 140 patients (36.8%) presented in baseline sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF at the beginning of the procedure. Patients in SR or with AT underwent shorter procedures (SR: 173 (132–213) minutes vs. AT: 161 (120–203) minutes vs. AF: 226 (154–249) minutes; P=0.002) with more frequent termination to SR (SR: 87.9% vs. AT: 81.3% vs. AF: 56.3%; P&amp;lt;0.001) than patients with AF. Periprocedural AT cycle length was longer in patients presenting in SR than in those with AT or AF (SR: 320 (265–370) ms vs. AT: 270 (240–310) ms vs. AF: 245 (193–278) ms; P&amp;lt;0.001). Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (SR: 96.4% vs. AT: 97.1% vs. AF: 87.5%; P=0.033). During a median follow-up of 290 (181–680) days, patients in baseline SR developed arrhythmia recurrences less often (SR: 36.4% vs. AT: 49.5% vs. AF: 68.8%; P=0.002) compared to patients with AT or AF. Conclusions Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favourable mid-term success rate. Restoration of SR prior to ablation might improve long-term outcome by reducing the risk for recurrent arrhythmia.

Atrial fibrillation is an independent risk factor for heart failure progression and pump failure mortality in HFpEF:: a propensity score matched analysis of the TOPCAT Americas study

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) is associated with excess mortality and cardiovascular (CV) hospitalizations in HF patients (pts) with preserved systolic function (pEF) but the contributing factors to these outcomes are not known.. Purpose To analyze the independent impact of AF on clinical outcomes of HFpEF pts in the TOPCAT AMERICAS study using propensity score matched (PSM) cohorts to account for confounding by other comorbidities. Methods Study cohorts were PSM matched for 20 clinical, demographic &amp; ECG variables. 3 matched cohorts based on baseline rhythm status at study entry were compared viz. subjects in sinus rhythm (SR), subjects in AF on baseline ECG &amp; subjects with Any AF event by history or ECG. We analyzed CV mortality, adjudicated modes of death &amp; morbidity during a mean follow up period of 2.9 yrs. Results 418 subjects in SR (SR cohort) were PSM with 418 subjects in AF on baseline ECG (AF on ECG cohort) &amp; 418 pts with any AF event by history or ECG (Any AF cohort) at study entry. Any AF increased the risk of CV death (D), pump failure death (PFD), CV and HF hospitalization (H) and HF progression. AF on ECG increased risk of CVD, CVH, HFH and PFD (Tables). Neither AF cohort increased risk of sudden death (SD) {Figure}. Conclusion 1. AF is an independent risk factor for worsening CV outcomes in HFpEF. 2. This increased risk is due to a selective increase in symptomatic HF progression from early to advanced HF, HFH and PFD in advanced HF rather than SD. 3. Loss of AV synchrony &amp; rate control in AF can independently impact HF progression in HFpEF with consequent HFH and PFD. Restoration of SR may offer benefits for CV outcomes in HFpEF &amp; warrants evaluation.