Atrial Rate Research Articles

REDUCTION OF HEART RATE VIA P2X4 RECEPTOR ACTIVATION AS A PROMISING TREATMENT STRATEGY IN PULMONARY ARTERIAL HYPERTENSION

Objective: Mounting evidence suggest that the ATP-sensitive ionotropic P2X4 receptor (P2X4R) improves cardiac performance and optimizes myocardial energy demand by reducing chronotropy. Here, we set to investigate whether the digitalis-like effect of the P2X4R in the sinus node was preserved in rats with right heart failure due to pulmonary arterial hypertension (PAH). Design and method: Male Wistar rats received a single subcutaneous injection of either monocrotaline (MCT; PAH group) or vehicle (CTRL group). Right heart failure associated to PAH normally occurs in Wistar rats 21 to 25 days after MCT administration. Myographic recordings were performed in spontaneously beating atria (chronotropic effect) isolated from both animal groups. Results: Baseline spontaneous atrial rate was 250 ± 5 (n = 26) bpm in CTRL and 237 ± 7 bpm (n = 23) in PAH group (p > 0.05). ATP (0.01–1 mM) concentration-dependently reduced the spontaneous atrial rate of both animal groups. The negative chronotropic effect of ATP (100 M) was smaller in PAH rats (-9 ± 2%; n = 14 vs. -22 ± 4%; n = 25, p < 0.05), but this divergence was attenuated upon increasing the concentration of ATP to 1 mM (CTRL: -54 ± 5%; n = 15 vs. MCT: -50 ± 7%; n = 8; p > 0.05). The P2X4R antagonist, 5-BDBD (10 M), attenuated the negative chronotropic action of ATP (100 M) in CTRL (from -19 ± 5% to -13 ± 3%; n = 5, p > 0.05) and PAH (from -8 ± 3% to 1 ± 8%; n = 4, p > 0.05) rats. The positive allosteric modulator of P2X4R, ivermectin (30 M), potentiated the negative chronotropic effect of ATP (100 M) in CTRL (from -31 ± 5% to -56 ± 14%; n = 5, p > 0.05) and PAH (from -12 ± 6% to -24 ± 9%; n = 4, p < 0.05). The non-selective P2XR agonist, CTP (1 mM), which contrary to ATP does not breakdown into adenosine, also decreased atrial chronotropy in CTRL (-24.31 ± 6.73%; n = 6) and PAH (-11.82 ± 1.98%; n = 6) rats. Conclusions: Data suggest that the negative chronotropic effect of P2X4R activation is preserved in atria of rats with heart failure associated to PAH, thus strengthening the hypothesis that heart rate reductions using this ATP-sensitive receptor may increase cardiac performance in patients with PAH-induced heart failure.

High-rate atrial pacing to reduce left-sided filling pressures: a combined computational and clinical pilot study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): This work was supported by the Netherlands Organisation for Scientific Research (NWO- ZonMw, VIDI grant 016.176.340 to J.L.) and the Dutch Heart Foundation (ERA-CVD JTC2018 grant 2018T094; Dr. Dekker Program grant 2015T082 to J.L.) Background In heart failure patients, interventions to reduce elevated left ventricular (LV) filling pressure improve symptoms and reduce the risk of hospitalization. In this combined computational-clinical study, we explore high-rate atrial pacing as an alternative intervention to reduce LV filling pressure. Methods First, the theoretical basis was explored in a computational model of reduced LV compliance and various fixed atrioventricular delays. Second, an explorative clinical study was conducted in 19 paroxysmal atrial fibrillation (AF) patients undergoing pulmonary vein isolation (PVI) with sinus rhythm at the beginning of the procedure. Prior to the PVI, atrial pacing rate was gradually increased from resting heart rate to Wenckebach point with 10bpm increments. LA pressure was continuously monitored with a fluid-filled transseptal catheter. Results Computational modelling demonstrated a parabolic relationship between atrial pacing rate and LA pressure depending on atrioventricular delay (Figure A). In patients (Figure B), intermediately increased rates (60bpm[60-70], median[IQR], to 90bpm[73-100], respectively) reduced LA pressure from 16.0mmHg[14.0-20.5] to 14.0mmHg[10.8-16.8]. Highly increased rates (130bpm[120-140]) significantly increased LA pressure to 26.0mmHg[21.5-27.8]. Conclusions Both the model simulations and the subsequent clinical pilot study support the hypothesis that high-rate atrial pacing can reduce left-sided filling pressure. However, inter-patient variability of response to high-rate pacing was observed, to which simulations identified atrioventricular conduction to be a potential source.

Capability of guideline-conform remote atrial high rate episode monitoring with a single-chamber implantable defibrillator with atrial sensing

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): BIOTRONIK, Berlin, Germany Introduction Device-detected atrial high-rate episodes (AHRE) and their burden progression are associated with an increased risk for thromboembolic events in correlation with CHA2DS2-VASc score and AHRE burden. To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend the monitoring of AHRE progression along pre-specified strata (6min…<1h, 1h…<24, ≥24h). We sought to assess the capability of a single-lead implantable cardioverter defibrillator (ICD), that is equipped with an atrial dipole for atrial sensing, to remotely detect and monitor AHRE burden progression in patients with standard indication to single-chamber ICD. Methods From the MATRIX (Management and Detection of Atrial Tachyarrhythmias in Patients Implanted With BIOTRONIK DX Systems) registry, we analyzed remotely transmitted, and electrogram (IEGM) AHREs in a subset of patients with remote transmissions and without history of long-standing AF at baseline. For each patient, we selected the first occurring episode per duration stratum and the first subsequent occurrence when progressing to a stratum of any longer duration. After episode adjudication by an independent electrophysiologist, we assessed the classification performance of the device (positive predictive value [PPV]) and analyzed AHRE onset and progression pathways. Results Of the MATRIX cohort, 1,746 patients matched the inclusions criteria (see table for patient characteristics) and 1,451 had no AF history. Of the 258 patients with AHREs (14.8%), 450 out of 465 evaluated episodes were correctly classified as AHRE. Reasons for misclassification were artifact (13) and R-wave oversensing (2). PPV was 96.8% (95% confidence interval 94.7%-98.2%). Grouped by stratum, PPV was 93.9%, 99.5% and 100% for 6min…<1h, 1h…<24 and ≥24h, respectively. Ninety six of 240 patients (40.0%) with a first episode according to the pre-specified strata were progressing to a stratum of longer duration and 9 patients (3.8%) had further progression (see Figure). In 119 out of 1,451 patients without AF history (8.2%), the device detected AHRE and 81 of them (4.6% of analysis set) had a mid to high risk for stroke and were not on anticoagulation therapy. In 121 out of 295 patients with known history of paroxysmal and persistent AF (41.0%), the arrhythmia was confirmed by the device. Discussion and Conclusion: The single-chamber ICD with atrial sensing capabilities correctly classified ≈97% of all adjudicated AHREs ≥6min. About 7% of patients had device-detected AHRE onset and/or progression and a mid to high stroke risk. These patients would potentially benefit the most from a guideline-conform AF monitoring strategy to timely initiate anticoagulation medication for stroke prevention.

Assessment of atrial fibrillation catheter ablation outcomes in patients with hypertrophic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) is a frequent manifestation of hypertrophic cardiomyopathy (HCM) and it is associated with increased risk for thromboembolic events and worsening of heart failure. AF is usually refractory to antiarrhythmic drugs in cases with HCM and catheter ablation may be useful in such patients. Purpose We aimed to evaluate outcomes of both cryoballoon and radiofrequency (RF) AF catheter ablation in patients with HCM. Methods All of the patients with HCM who underwent AF catheter ablation between January 2014 and January 2022 were screened and patients with available follow-up datas were included. Results A total of 44 patients were enrolled. Mean age was 54.2±12.6 years and 45.5% of the patients were female. RF ablation was performed in 23 cases and remaining patients underwent cryoablation. Median follow-up was 42.5 (4-94) months. Baseline characteristics were listed in Table-1. Only pulmonary vein isolation was performed in 25 (56.8 %) patients while additional ablation procedures including left atrial appendage isolation and linear ablation were required in other cases. Periprocedural complications occured in 6 cases. Atrial tachycardia recurrence developed in half of patients and mortality occured in 2 (4.5 %) cases during follow-up (Table-2). Six months recurrence free survival (RFS) rate was 90.9% and 1 year RFS was 86.1% however RFS rate reduced to 58.2 after 3 years follow-up. Atrial tachycardia recurrence rates, complication and mortality rates were similar between the patients who underwent cryoablation and RF ablation. Changes in NYHA class and BNP levels were not significant during follow-up, however EHRA class was distinctly improved (II vs. I; p<0.001). Conclusion Although long term outcomes of AF catheter ablation is not satisfactory; it is effective in short term rhythm control with reasonable complication rates. Recurrence rates are similar between RF and cryoablation.

Combined pulmonary vein isolation and cavotricuspid isthmus ablation shows no benefit in recurrence of atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is the mainstay of catheter ablation (CA) for atrial fibrillation (AF). Strategies have been proposed to improve the success rate of CA, such as prophylactic cavotricuspid isthmus (CTI) ablation. Despite some studies providing no, or limited, incremental benefit of CTI ablation in patients with AF, it is still frequently performed worldwide. Purpose The aim of this study is to examine whether CTI ablation, combined with PVI, is associated with improvement in recurrence of AF, compared with PVI alone in AF patients with or without atrial flutter (AFL). Methods We conducted a retrospective analysis of CA for AF performed at a tertiary center between September 2004 and December 2020. The procedures were divided in two groups: "PVI alone" and "PVI plus CTI ablation". Demographic, clinical, and procedure related data was retrieved. Atrial fibrillation recurrence rate at one year was analyzed for both groups and compared using logistic regression. Results A total of 453 procedures were analyzed: PVI alone (n=378; 83.4%) and PVI with CTI ablation (n=75; 16.6%). In the PVI alone group, 12.9% of the patients had concomitant typical AFL and in the PVI plus CTI ablation, 45.8% had typical AFL. Mean age was 57.3±12.1 years, with 63.6% male patients. At one year, AF recurrence rate was higher in the combined PVI with CTI ablation group (30.4%; n=21), compared with the PVI alone group (28.4%; n=97), with no statistical difference between the two groups (Odds Ratio [OD] 1.10; 95% confidence interval [CI] 0.62-1.94; p=0.73). In the subgroup analysis, there was no difference in recurrence between patients with AF without AFL (OR: 1.9; 95% CI: 0.39-9.36; p=0.43), and in patients with AF with concomitant AFL (OR: 10.0; 95% CI: 0.9-110.3; p=0.06). Conclusion In AF patients, irrespective of the presence of typical AFL, additional CTI ablation, compared with PVI alone, was not associated with improvement in recurrence of AF.

Paced P-wave duration as a significant predictor for atrial high-rate episodes in patients with cardiac implantable electronic devices

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial pacing can unmask or aggravate a preexisting interatrial block (IAB). Purpose The purpose of our study was to determine whether atrial pacing is associated with the development of atrial high-rate episodes (AHRE) during follow-up. Methods Patients with cardiac implantable electronic devices (CIED), no previous documented atrial fibrillation, and with a 6-month minimum follow-up were included. Sinus and paced P-wave duration were measured. AHRE was defined as an episode of atrial rate ≥ 225 bpm with a minimum duration of 5 min, excluding those documented during the first three months after implantation. Results Two hundred twenty patients were included (75 ± 10 years, 61% male). After a mean follow-up of 59±25 months, 46% of patients presented AHRE. Mean paced P-wave duration was significantly longer than sinus P-wave duration (154±27 vs 115±18 ms; p < 0.001). Sinus and paced P-waves were significantly longer in those who developed AHRE (sinus: 119±20 vs 112±16; p = 0.006; paced: 161±29 vs 148±23; p < 0.001). A paced P-wave ≥160 ms was the best predictor of AHRE, especially those lasting >24 h (OR 4.2 (95% CI) [1.6-11.4]; p = 0.004). In a multivariate analysis, a paced P-wave ≥160 ms (OR: 1.84; 95% CI [1.03–3.28]; p = 0.038), a CHA2DS2-VASc score ≥4 (OR: 2.01; 95% CI [1.13–3.55]; p = 0.016), and a LA SI dimension ≥ 55 mm (OR 2.69; 95% CI [1.48–4.90]; p = 0.001) were independent predictors augmenting AHRE. Conclusion Atrial pacing significantly prolongs P-wave duration and is associated with further development of AHRE. A paced P-wave ≥160 ms is a strong predictor of AHRE and should be taken into consideration as a new definition of IAB in the presence of atrial pacing.

C5 IMPACT OF ATRIAL HIGH RATE EPISODES ON PROGNOSIS IN PACEMAKER PATIENTS: A SINGLE CENTRE EXPERIENCE

Abstract Background The occurrence of high atrial rate episodes (AHRE) is growing in importance due to the increasing number of patients with implantable cardiac electronic devices (CIED). As a result, clinicians need to balance the benefits of a pharmacological therapy against the risks involved. To date, there are no clear evidence on the long–term effects of AHRE, nor are there any specific recommendations to help physicians make the most appropriate treatment choice. Methods We enrolled 732 patients with CIED followed in the Arrhythmology department of San Filippo Neri Hospital, in Rome and with remote home monitoring. Only patients with single–chamber, dual–chamber and biventricular pacemakers (CRT–P) were included. All patients had post–implantation follow–up at 6 months and one year. The minimum follow–up duration considered was 24 months. Patients with permanent pre–implant atrial fibrillation were excluded. Results Among the enrolled cohort, AHRE were found in 170 (23.2%) patients. The occurrence of AHRE was significantly related to older age (p = 0.001 HR 1.02 CI 95%), lower ejection fraction (p = 0.027 HR 0.98 CI 95%) and severe mitral valvulopathy (p = 0.003 HR 1.7 CI 95%). The presence of AHRE increased the risk of cryptogenic stroke only for episodes over 24 hours (p = 0.02 HR 1.6 CI 95%) and increased mortality (HR 1.32 CI 95%), although not significantly (p = 0.132). Conclusion AHRE are associated with adverse events and may increase mortality in patients with CIED. Their monitoring and detection is necessary for an appropriate management of treatments. Randomised studies are needed to clarify the criteria for thromboembolic prevention in the context of AHRE.

Effect of Preablation Glycemic Control on Outcomes of Atrial Fibrillation Patients With Diabetes Mellitus Following Valvular Surgery Combined With the Cox-Maze IV Procedure.

BackgroundThis study was performed to assess the effect of preablation glycemic control on atrial fibrillation recurrence rates after heart valve surgery concomitant with Cox-Maze IV ablation.MethodsTwelve-month preablation trends in glycemic control were studied. Recurrence and clinical outcome data were obtained during a mean follow-up period of 36.7 ± 23.3 months postablation.ResultsHigher glycated hemoglobin (HbA1c) at the time of ablation was associated with higher postablation recurrence rates. The cumulative atrial fibrillation recurrence-free survival of patients with HbA1c ≥7.5% at the time of operation at 12, 24, 36 and 48 months was 97.1, 78.3, 54.2, and 36.3%, respectively (P < 0.001), and 100, 84.9, 37.2, and 16.2% for patients who preoperatively had an upward trend in HbA1c, respectively (P < 0.001).ConclusionMaintaining a downward trend in HbA1c during the 12-month period before the operation and an HbA1c value < 7.5% at the time of the operation reduced the recurrence of AF among patients who underwent heart valve surgery concomitant with the Cox-Maze IV procedure.

Application values of right atrial volume, myocardial strain and strain rate in evaluating right atrial function in patients with essential hypertension with normal left ventricular ejection fraction

Objective: To explore the application values of right atrial (RA) volume, myocardial strain and strain rate in evaluating right atrial functions in patients with essential hypertension (EHT) with normal left ventricular ejection fraction (LVEF). Methods: We retrospectively collected a total of 126 EHT patients with normal LVEF, including 66 males and 60 females, age from 18 to 83(48±15) years from the Affiliated Changzhou No.2 People's Hospital with Nanjing Medical University from March, 2018 to May, 2020. According to the left ventricular mass index, those patients were divided into without left ventricle hypertrophy (LVH) group (n=66) and LVH group (n=60), and 83 healthy volunteers were enrolled as control group, which including 42 males and 41 females, age from 14 to 88 (48±16) years. The total, passive and active RA emptying fraction (total RAEF, passive RAEF and active RAEF) were measured by using RA volumes method. The RA strain (S-reservoir, S-conduit, S-booster pump) and the strain rate (SR-reservoir, SR-conduit, SR-booster pump) were measured by two-dimensional speckle tracking echocardiography. Total RAEF, S-reservoir, and Sr-reservoir represented the reservoir function, while passive RAEF, S-conduit, and Sr-conduit represented the conduit function, and active RAEF, S-booster pump and Sr-booster pump represented the booster pump function, respectively. Than the values between the EHT patients and normal subjects, and the values among the EHT patients without LVH, EHT patients without LVH and normal subjects were compared. Results: The value of active RAEF was significantly lower in EHT patient than normal controls (40.1%±10.5% vs 45.4%±11.1%,P=0.001). There were significant differences among EHT patients without LVH, EHT patients with LVH and normal subjects in passive RAEF and active RAEF (passive RAEF: 40.2%±9.3% vs 36.4%±10.7% vs 36.5%±9.4%, P=0.038, active RAEF: 39.8%±10.6% vs 40.4%±10.4% vs 45.4%±11.1%, P=0.002). There were significant differences in S-reservoir, S-conduit, S-booster pump, SR-reservoir, SR-conduit and SR-booster pump between EHT patients and normal subjects [S-reservoir: 34.8%±13.7% vs 45.0%±13.3%, S-conduit: 18.3%±9.4% vs 26.5%±9.6%, S-booster pump: 16.4%±7.3% vs 18.6%±7.1%, SR-reservoir: (1.6±0.6)/s vs (2.0±0.6)/s, SR-conduit: (-1.2±0.5)/s vs (-1.6±0.6)/s, SR-booster pump: (-1.7±0.6)/s vs (-2.3±0.6)/s; all P<0.05]. The trend tests showed normal controls achieved the largest the absolute values of S-reservoir, S-conduit, SR-reservoir, SR-conduit, SR-booster pump, followed by EHT patients without LVH and EHT patients with LVH(all P<0.001). Conclusions: Using RA volume, myocardial strain and strain rate can detect the RA impaired reservoir, conduit, and the booster pump functions in EHT patients with normal LVEF, and the RA functions were damaged more significantly in EHT patients with LVH.

PO-690-03 ATRIAL ELECTROMECHANICAL DISSOCIATION AS A NOVEL NON-INVASIVE PARAMETER OF EARLY REMODELING PROGRESSION DURING ATRIAL FIBRILLATION

Electromechanical assessment during atrial fibrillation (AF) remains a significant knowledge gap in patient-specific characterization of atrial remodeling. Study electromechanical remodeling progression in a long-term pig model of AF and establish the clinical prognostic value of the atrial electromechanical relationship. Experimental group of pigs with AF (N=15) and a prospective clinical cohort (N=95) of symptomatic AF patients (episode duration ≤6 months) undergoing atrial remodeling characterization. Atrial electromechanical remodeling was assessed using simultaneous surface ECG recordings and tissue Doppler imaging (TDI) signals during echocardiography studies in AF. Electromechanical dissociation (EMD) was defined as faster atrial electrical activation rates (EAR) than the simultaneous counterpart TDI-derived mechanical activation rates (MAR). In patients, the primary outcome was cardioversion within a 24-h window after flecainide. Secondary outcomes were cardioversion of persistent AF and recurrences at 1-year. Pigs developed progressive EMD during the first weeks of AF-related remodeling (5-to-21 weeks after protocol initiation). EMD reached 2.29±2.47 Hz (p=0.04) at 12 weeks after the first recorded AF episode lasting ≥6 seconds. In pigs with long-lasting AF (342.5±86.6 d of self-sustained AF), high-resolution electroanatomical mapping and transesophageal echocardiography imaging demonstrated overt EMD (EAR-MAR=3.49±0.67 Hz) between local EARs from unipolar electrograms and the corresponding spatially and temporally synchronized MARs. In patients (55.0±11.6 years old), regardless of AF classification (paroxysmal or persistent AF), EMD was associated with failure of pharmacological cardioversion within the 24-h window after flecainide. EMD provided the highest increase in certainty for the primary outcome when added to AF classification compared to the increase provided by clinical variables and EARs. EMD was also associated with long-term AF recurrences both in the overall AF population and in the patient subset with persistent AF. Figure 1 summarizes the main study results. Atrial EMD is an early indicator of AF remodeling progression with prognostic value in acute and long-term rhythm control.

Utility of speckle-tracking echocardiography for predicting atrial fibrillation following ischemic stroke: a systematic review and meta-analysis.

Undiagnosed atrial fibrillation (AF) is one of the main sources of cryptogenic stroke. And strain indices measured by speckle-tracking echocardiography are associated with atrial remodeling supposed to be the substrate of AF. Therefore, there is a strong need for evaluating the utility of speckle-tracking echocardiography to predict the likelihood of AF in patients with cryptogenic stroke. PubMed, Embase and Cochrane Database were searched for studies. The random-effects model was used to calculate the pooled results, and summary receiver operating characteristic curve (SROC) analysis was performed to show the overall predictive value. There were 1483 patients with cryptogenic stroke from 8 studies. Meta-analysis showed that strain indices including global longitudinal strain (GLS) (mean difference [SMD]: -0.22, 95% confidence interval [95% CI] -0.40 to -0.04), left atrial reservoir strain (εR), (SMD: -0.87, 95% CI -1.26 to -0.48, conduit strain (εCD) (SMD: -0.56, 95% CI -0.81 to -0.30), contractile strain (εCT) (SMD: -1.00, 95% CI -1.39 to -0.61), and left atrial reservoir strain rate (SRe) (SMD: -0.54, 95% CI -0.80 to -0.28) measured at the period of cryptogenic stroke was significantly decreased in patients with AF occurrence compared to without. SROC analysis suggested an acceptable predictive efficiency of εR for AF occurrence (AUC = 0.799). For patients after cryptogenic stroke, GLS, εR, εCD, εCT and SRe were significantly decreased in AF occurrence compared with non-occurrence. But there was no value in left atrial reservoir strain rate (SRs) and contractile strain rate (SRa) for predicting AF.

Association of Non-Alcoholic Fatty Liver Disease and Hepatic Fibrosis with Epicardial Adipose Tissue Volume and Atrial Deformation Mechanics in a Large Asian Population Free from Clinical Heart Failure.

Non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease share several cardiometabolic risk factors. Excessive visceral fat can manifest as ectopic fat depots over vital organs, such as the heart and liver. This study assessed the associations of NAFLD and liver fibrosis with cardiac structural and functional disturbances. We assessed 2161 participants using ultrasound, and categorized them as per the NAFLD Fibrosis Score into three groups: (1) non-fatty liver; (2) fatty liver with low fibrosis score; and (3) fatty liver with high fibrosis score. Epicardial fat volume (EFV) was measured through multidetector computed tomography. All participants underwent echocardiographic study, including tissue Doppler-based E/e’ ratio and speckle tracking-based left ventricular global longitudinal strain, peak atrial longitudinal strain (PALS), and atrial longitudinal strain rates during systolic, early and late-diastolic phases (ALSRsyst, ALSRearly. ALSRlate). Larger EFV, decreased e’ velocity, PALS, ALSRsyst, and ALSRearly, along with elevated E/e’ ratio, were seen in all groups, especially in those with high fibrosis scores. After multivariate adjustment for traditional risk factors and EFV, fibrosis scores remained significantly associated with elevated E/e’ ratio, LA stiffness, and decreased PALS (β: 0.06, 1.4, −0.01, all p < 0.05). Thus, NAFLD is associated with LV diastolic dysfunction and subclinical changes in LA contractile mechanics.

Left atrial appendage strain and strain rate using cardiovascular magnetic resonance feature tracking: preliminary study on feasibility and reproducibility

Over the past decade, left atrial appendage (LAA) function has been widely recognised as an important marker to predict the onset of adverse cardiovascular events.1 Its active contraction prevents thrombus formation. When it is lacking, such as in atrial fibrillation,2 the thromboembolic risk is increased markedly. The mechanical properties of the LAA may regulate haemodynamic function through modulation of left atrial pressure in conditions of volume overload and increased left atrial pressure.

Optimal single procedure strategy of pulmonary vein isolation with cryoballoon or radiofrequency and non-pulmonary vein triggers ablation for non-paroxysmal atrial fibrillation.

BackgroundLimited data exist on pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) ablation and additional non-pulmonary vein trigger ablation for non-paroxysmal atrial fibrillation (non-PAF). We aimed to assess the outcomes of first-stage catheter ablation for non-PAF patients.MethodsInitial PVI was performed on 734 non-PAF patients (age: 64 ± 10 years; male: 584 (80%)) between September 2014 and June 2018 [315 (43%), CB ablation; 419 (57%), RF catheter]. A logistic regression model was used to match 257 pairs (514 patients) according to the propensity scores (CB or RF group). After PVI, additional non-PV trigger ablation was performed if induced by isoproterenol. We analysed the clinical outcomes of both groups.ResultsThe mean procedural time was significantly shorter in the CB group (125 [range, 89–165] min) than in the RF group (190 [160–224] min; P < 0.001). The 1-year Kaplan-Meier event rate revealed similar atrial fibrillation-free survival rates between the two groups (CB: 77.9%, RF: 82.3%; log-rank P = 0.111). The additional ablation percentage for non-PV foci (CB: 39%, RF: 41%; P = 0.653) and complication incidence (CB: 5%, RF: 4%; P = 0.670) were also similar.ConclusionsIn non-PAF patients, the combination strategy of PVI using CB or RF ablation and non-PV trigger ablation achieved comparable outcomes.

Incremental diagnostic value of CMR-derived LA strain and strain rate in dialysis patients with HFpEF

ObjectivesTo test whether left atrial (LA) strain and strain rate add incremental value in the diagnosis of heart failure with preserved ejection fraction (HFpEF) in dialysis patients over clinical and conventional parameters only. BackgroundHFpEF frequently occurs in dialysis patients, however, the diagnosis of HFpEF is difficult. Although HFpEF is always companied with LA dysfunction, the performance of novel LA parameters, LA strain, and strain rate, in the diagnosis of HFpEF among dialysis patients remains unknown. MethodsIn the study, 153 dialysis patients (57 without HFpEF and 96 with HFpEF) and 52 healthy controls underwent cardiovascular magnetic imaging (CMR). Three components of LA strain and strain rate, including reservoir, contractile, and booster pump, were assessed via the CMR feature tracking module. Extra diagnostic value was examined by Harrell’s C-statistic. ResultsCompared with healthy controls and dialysis patients without HFpEF, dialysis patients with HFpEF had significantly impaired LA reservoir (εs) and contractile (εe) strain and strain rate (SRs, SRe), all p < 0.0001. Among these parameters, εs, εe, and SRe showed relatively high accuracy in diagnosing HFpEF among dialysis patients (areas under the curve: 0.84, 0.91, and 0.90, respectively). Reduction of εs, εe, and SRs provided incremental diagnostic value over conventional clinical and echocardiogram parameters. Combined with εs, εe or SRs, the diagnostic performance was further improved (Harrell’s C-statistic: 0.83 vs. 0.96, 0.97, and 0.97, respectively, all p < 0.0001). ConclusionsCMR-derived εs, εe, and SRs might add incremental diagnostic value over conventional indexes in diagnosing HFpEF among dialysis patients.

Left atrial contraction strain and controlled preload alterations, a study in healthy individuals

BackgroundIn order to assess left atrial contractile function in disturbed circulatory conditions, it is necessary to have a clear understanding of how it behaves in a normal resting state with changes in loading conditions. However, currently the understanding of this relationship is incomplete. We hypothesize that in healthy individuals, left atrial contraction strain and its peak strain rate are increased or decreased by increasing or decreasing preload, respectively.MethodsControlled maneuvers used to change preload included continuous positive airway pressure by mask (CPAP 20 cmH2O) for preload decrease, and passive leg raise (15 degrees angle) for preload increase. Cardiac ultrasound 4-chamber views of the left atria and left ventricle were acquired at baseline and during maneuver. Acquired images were post processed and analyzed offline. Comparisons were made using paired t-test and means with 95% confidence interval.ResultsThere were 38 participants, complete results were obtained from 23 in the CPAP maneuver and 27 in the passive leg raise maneuver. For the CPAP group, left atrial contraction strain was 11.6% (10.1 to 13.1) at baseline and 12.8% (11.0 to 14.6) during the maneuver (p = 0.16). Left atrial contraction peak strain rate was − 1.7 s− 1 (− 1.8 to − 1.5) at baseline and − 1.8 s− 1 (− 2.0 to − 1.6) during the maneuver (p = 0.29). For the passive leg raise-group, left atrial contraction strain was 10.1% (9.0 to 11.2) at baseline and 10.8% (9.4 to 12.3) during the maneuver (p = 0.28). Left atrial contraction peak strain rate was − 1.5 s− 1 (− 1.6 to − 1.4) at baseline and − 1.6 s− 1 (− 1.8 to − 1.5) during the maneuver (p = 0.29). Left atrial area, an indicator of preload, increased significantly during passive leg raise and decreased during CPAP.ConclusionIn healthy individuals, left atrial contraction strain and its peak strain rate seem to be preload-independent.Trial registrationThe study was 2018-02-19 registered at clinicaltrials.gov (NCT03436030).

Atrial remodelling comparison after maze-3 and cryo-maze procedures in combined cardiac interventions: a retrospective study

Background. The maze procedure aims to eliminate atrial fibrillation (AF), restore sinus rhythm (SR) and atrial contractility. However, conflicting evidence exists regarding the extent of atrial remodelling in various techniques, which directed the focus of our study.Objectives. An atrial remodelling comparison after a cut-and-sew maze-3 surgery and its biatrial cryo-maze modification using 2D echocardiography.Methods. The study is a retrospective uncontrolled interrupted two-cohort time-series trial, with patients selected by pseudorandomisation according to a normal sinus rhythm-maintaining AF surgery method. A total of 217 maze-3 and 113 cryo-maze combined cardiac interventions have been performed within 2012–2021. The interventions included valve repair, coronary artery bypass grafting and their combination. Due to differences in long-term follow-up, the cohorts were pseudorandomised to select by 50 restored vs. maintained sinus rhythm patients using a nearest-neighbour classifier coupled with logistic regression. Mean follow-up period was 6 (1–17) months. The patients had paroxysmal, persistent and longstanding persistent AF. Echocardiography values prior to and long-term post-surgery were further analysed to determine the atrial remodelling dynamics. Results. A statistically significant atrial volume reduction is evident in a long-term within-cohort comparison. Meanwhile, a statistically more pronounced remodelling is observed between cohorts after maze-3 procedure. The cohort 1 vs. 2 estimates are: mean left atrial volume 120/125 mL3 (p = 0.011), left atrial size in apical view 52/53 mm (p = 0.023), right atrial size in apical view 58/62 mm (p = 0.004), right atrial size in parasternal short axis view 43/45 mm (p = 0.004), right atrial area in apical 4-chamber view 25/28 cm2 (p = 0.007). Maintained atrial pacing patients had positive systolic atrial function recovery rates (E/A ratio increased to average 1.5) in the long-term in both comparison cohorts.Conclusion. Remodelling is biatrial after all the maze procedures compared. A more pronounced atrial volume reduction occurs after maze-3 surgery. The presence of sinus rhythm is facilitated by cardiac conduction leading to mechanical and electrical remodelling of the atria.

Efficacy and Safety of Catheter Ablation Combined with Left Atrial Appendage Closure in the Treatment of Atrial Fibrillation: A Systematic Review and Meta-Analysis.

BackgroundCatheter ablation combined with left atrial appendage closure is effective in treating atrial fibrillation. However, the effectiveness of this combined treatment compared with catheter ablation alone is still controversial.MethodsWe searched studies in databases, including The Cochrane Library, PubMed, EMBASE, and Web of Science, that compared catheter ablation combined with left atrial appendage closure and catheter ablation alone in the treatment of atrial fibrillation. These studies reported at least one of the following outcomes: the freedom from atrial arrhythmia rate, the procedure time, the fluoroscopy time, perioperative complications, thromboembolic events, and bleeding events during follow-up. The risk ratio and standard mean difference with 95% CI were analyzed by the random-effects model.ResultsFive studies involving 699 people were included in our meta-analysis. We found no significant difference in the freedom from atrial arrhythmia rate (risk ratio = 0.93, 95% CI = 0.83-1.04, I2 = 0%, P = .21) between the 2 groups. Catheter ablation combined with left atrial appendage closure showed significantly longer procedure and fluoroscopy times than catheter ablation alone (standard mean difference = 1.26, 95% CI = 0.85-1.67, P < .00001 and standard mean difference = 1.19, 95% CI = 0.53-1.85, P = .0004, respectively). With regard to safety outcomes, no significant differences were observed in perioperative complications (RR = 1.62, 95% CI = 0.99-2.63, I2 = 0%, P = .05), thromboembolic events (RR = 0.67, 95% CI = 0.15-3.11, I2 = 0%, P = .61), or bleeding events (RR = 0.67, 95% CI = 0.11-3.88, P = .65) between the 2 groups during follow-up.ConclusionThe freedom from atrial arrhythmia rate and safety outcomes of catheter ablation combined with left atrial appendage closure are similar to those of catheter ablation alone. Catheter ablation combined with left atrial appendage closure appears to have longer procedure and fluoroscopy times than catheter ablation alone.

Atrial High-Rate Episodes Detected by Cardiac Implantable Electronic Devices: Dynamic Changes in Episodes and Predictors of Incident Atrial Fibrillation

Simple SummaryAtrial high rate episodes (AHRE) detected by cardiac implantable electronic devices (CIEDs) may be associated with a risk of progression towards long-lasting episodes (≥24 h) and clinical atrial fibrillation (AF). Identification of this subset of patients is key to promptly starting oral anticoagulant therapy and possibly avoiding stroke and systemic thromboembolism. In the present study, we describe the clinical characteristics of 104 retrospectively enrolled patients with AHRE episodes lasting 5 min–23 h 59 min, no AF at 12-lead ECG, and no history of prior clinical AF. Moreover, we define predictors of the composite outcome of clinical AF and/or AHRE episodes lasting ≥24 h. Over a median follow-up of 24.3 (10.6–40.3) months, 31/104 (29.8%) patients experienced the composite outcome. Baseline CHA2DS2-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were independently associated with the composite outcome and with incident clinical AF as well. To conclude, in patients with AHRE, the incidence of clinical AF or AHRE episodes lasting ≥24 h is high. Baseline patients’ characteristics (CHA2DS2-VASc score) and AHRE duration may help to intensify monitoring and decision-making, being independently associated with clinical AF in a two-year follow-up.Background. Atrial high rate episodes (AHRE) detected by cardiac implantable electronic devices (CIEDs) may be associated with a risk of progression towards long-lasting episodes (≥24 h) and clinical atrial fibrillation (AF). Methods. Consecutive CIED patients presenting AHRE (with confirmation of an arrhythmia lasting 5 min–23 h 59 min, atrial rate ≥175/min, with no AF at 12-lead ECG and no prior clinical AF) were retrospectively enrolled. The aims of this study were to describe patients’ characteristics and the incidence of adverse events, and second, to identify potential predictors of the composite outcome of clinical AF and/or AHRE episodes lasting ≥24 h. Results. 104/107 (97.2%) patients (median age 79.7 (74.0–84.2), 33.7% female) had available follow-up data. Over a median follow-up of 24.3 (10.6–40.3) months, 31/104 (29.8%) patients experienced the composite outcome of clinical AF or AHRE episodes lasting ≥24 h. Baseline CHA2DS2-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were independently associated with the composite outcome (Hazard ratio (HR); 95% CI: 1.40; 1.07–1.83 and HR: 8.15; 95% CI 2.32–28.65, respectively). Baseline CHA2DS2-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were the only independent predictors of incident clinical AF (HR: 1.45; 95% CI 1.06–2.00 and HR: 4.25; 95% CI 1.05–17.20, respectively). Conclusions. In patients with AHRE, the incidence of clinical AF or AHRE episodes lasting ≥24 h is high in a two-year follow-up. Baseline patients’ characteristics (CHA2DS2-VASc score) and AHRE duration may help to intensify monitoring and decision-making, being independently associated with clinical AF at follow-up.

Mechanism of the effects of sodium channel blockade on the arrhythmogenic substrate of Brugada syndrome.

The mechanisms by which sodium channel blockade and high-rate pacing modify electrogram (EGM) substrates of Brugada syndrome (BrS) have not been elucidated. The purpose of this study was to determine the effect of ajmaline and high pacing rate on the BrS substrates. Thirty-two patients with BrS (mean age 40 ± 12 years) and frequent ventricular fibrillation episodes underwent right ventricular outflow tract substrate electroanatomical and electrocardiographic imaging (ECGI) mapping before and after ajmaline administration and during high-rate atrial pacing. In 4 patients, epicardial mapping was performed using open thoracotomy with targeted biopsies. Ajmaline increased the activation time delay in the substrate (33%; P = .002), ST-segment elevation in the right precordial leads (74%; P < .0001), and the area of delayed activation (170%; P < .0001), coinciding with the increased substrate size (75%; P < .0001). High atrial pacing rate increased the abnormal EGM duration at the right ventricular outflow tract areas from 112 ± 48 to 143 ± 66 ms (P = .003) and produced intermittent conduction block and/or excitation failure at the substrate sites, especially after ajmaline administration. Biopsies from the 4 patients with thoracotomy showed epicardial fibrosis where EGMs were normal at baseline but became fractionated after ajmaline administration. In some areas, local activation was absent and unipolar EGMs had a monophasic morphology resembling the shape of the action potential. Sodium current reduction with ajmaline severely compromises impulse conduction at the BrS fibrotic substrates by producing fractionated EGMs, conduction block, or excitation failure, leading to the Brugada ECG pattern and favoring ventricular fibrillation genesis.