Atrial Rate Research Articles

Impact of unipolar voltage criteria for left atrial posterior wall on atrial fibrillation recurrence after pulmonary vein isolation.

Beyond pulmonary vein isolation (PVI), additional therapeutic strategies for atrial fibrillation (AF) have not been established. Remodeling of the left atrium (LA) could impact AF recurrence post-PVI. We investigated the impact of unipolar voltage (UV) criteria for the LA posterior wall (LA-PW) on AF recurrence post-PVI. We reviewed the cases of 106 AF patients (mean age 63.8 years, nonparoxysmal AF: 59%) who underwent extensive encircling PVI by radiofrequency ablation guided by a 3-dimension mapping system, investigating the impact on AF recurrence of the UV criteria of the LA. Out of all patients, 26 patients had AF recurrence during post-PVI follow-up [median 603 days]. They showed a higher percentage of nonparoxysmal AF (80.8 vs. 52.5%, p = .011), longer AF duration (2.9 ± 2.7 vs. 1.0 ± 1.7 years, p = .002), and larger area size of UV < 2.0 mV in LA-PW (2.8 ± 1.8 vs. 1.0 ± 1.5 cm2 , p < .001) than those without recurrence. Cox Hazard analysis for AF recurrence adjusted by age, gender, AF duration, body mass index and left atrial volume index revealed that an area size over 2.0 cm2 of UV < 2.0 mV in LA-PW (HR 6.9 [95% CI:1.3-35.5], p = .021) posed independent risks for AF recurrence post-PVI. The atrial arrhythmia-free survival rate was higher in those with no area of UV < 3.0 mV in LA-PW compared to those with a sizable area (>2.0 cm2 ) of UV < 3.0 mV and <2.0 mV (95.0% vs. 74.2% vs. 57.1%, Log-Rank: p < .001). In the AF etiology of patients with AF recurrence, 9 of 14 patients who underwent the 2nd procedure had no PV reconnection, and 8 patients required the LA-PW isolation for their non-PV AF. UV criteria of LA-PW is a useful parameter for AF-recurrence post-PVI. Lower UV in LA-PW as an indication of electrical remodeling could indicate a higher risk of AF recurrence and the need for further therapeutic strategies.

Acute Coronary Syndrome Registry in Iwate Prefecture

Background: In Iwate Prefecture, the registration project for acute coronary syndrome started as a pilot project in 2014 and became a main project in 2016, enabling us to understand and verify the current situation in Iwate Prefecture.Methods: To obtain a comprehensive understanding of the present status of the region, we compiled data on the registration project for acute coronary syndrome in Iwate Prefecture.Results: The incidence/death ratio, which indicates the accuracy of registration, and the ambulance use rate increased over time. The percentage of 12-lead electrocardiogram (ECG) transmission implementation in all prefectures was still insufficient, at 7.5% in 2019. In contrast, in medical regions where transmission had already been introduced, 23.6–62.5% of cases had ECG transmission. The atrial fibrillation complication rate showed a slight upward trend over time, exceeding 10% in 2019. The incidence of pre-infarction angina was approximately 30% in this 2019 registry. For urgent recanalization therapy, urgent coronary angiography was performed in 89% of cases in 2019, and recanalization therapy was performed in an additional 83% of cases. These rates have also increased over time.Conclusion: It is necessary to continue to promote registration projects that provide an overall view of the region, provide data that can be returned to residents, and advise the government.

REACT DX registry: Real world REACTion to atrial high rate episodes detected in implantable cardioverter-defibrillator recipients with a DX lead.

Atrial fibrillation (AF) is associated with significant morbidity and is predicted by atrial high rate events. The early detection of AF is paramount to timely interventions to reduce the morbidity of AF. The DX ICD system combined with Home Monitoring® allows for continuous atrial rhythm monitoring without the need for a dedicated atrial lead. To establish the reaction to and timing of reactions to the detection of atrial high rate episodes (AHRE). A prospective cohort of DX ICD systems was followed up and the response to AHREs was collected and evaluated. A total of 234 patients were enrolled; an AHRE ⩾ 6 min was detected in 13.7% of patients (n= 32) within a mean follow-up duration of 16 months. A high rate of oral anticoagulation (OAC) prescription was seen with the detection of AHREs in patients with a not-low risk CHA2DS2-VASc score. There was a delay in this prescription highlighting the potential to improve the timeliness of patient care in this group of patients. The DX ICD system provides rapid and ongoing atrial rhythm monitoring such that physicians are rapidly aware of AHRE without the need for a dedicated atrial lead, but local protocols are needed to improve the response time of anti-coagulation prescription.

Can body position be arrhythmogenic?

IntroductionPalpitations occurring in specific body positions are often reported by patients, but the effect of body position on arrhythmia has received little research attention. We hypothesize that resting body position can exert pro-arrhythmogenic effects in various ways. For example, lateral body position is known to increase change atrial and pulmonary vein dimensions. MethodsThis observational study capitalizes on overnight polysomnography (PSG) recordings from a tertiary sleep clinic. PSGs were retrieved based on any mention of cardiac arrhythmia in the clinical report, irrespective of primary sleep diagnosis or (cardiac) comorbidities. Every instance of atrial ectopy was annotated and subgroups with a homogenous rate of atrial ectopy were created based on the Dunn index. A generalized linear mixed-effects model using age, sex, gender, sleep stage and body position was used to analyse the total amount of atrial ectopy in each combination of sleep stage and body position. Backward elimination was then performed to select the best subset of variables for the model. Presence of a respiratory event was then added to the model for the subgroup with a high atrial ectopy rate. ResultsPSGs of 22 patients (14% female, mean age 61y) were clustered and analysed. Body position, sleep stage, age or sex did not have a significant effect on atrial ectopy in the subgroup with a low rate of atrial ectopy (N = 18). However, body position did significantly affect the rate of atrial ectopy in the subgroup with a high rate of atrial ectopy (N = 4; 18%). Respiratory events significantly altered the atrial ectopy rate in only three body positions across two patients. DiscussionIn each individual with a high rate of atrial ectopy, the rate of atrial ectopy was significantly higher in either left or right decubital or supine position. Increase in atrial wall stretch in lateral decubital position and obstructive respiratory events in positional sleep apnea are two possible pathophysiological mechanisms, while avoidance of a body position due to symptomatic atrial ectopy in that position is an important limitation. ConclusionIn a selected cohort of patients with a high rate of atrial ectopy during overnight polysomnography, the occurrence of atrial ectopy is related to resting body position.

Abnormal transmitral flow: what is the rhythm?

Echocardiography was performed on 78-year-old woman for the follow-up of moderate mitral valve regurgitation (MR). A single-lead electrocardiographic (ECG) tracing showed bradycardia with irregular heart rhythm between 46 and 53 beats per minute. The echocardiographic image of pulsed wave Doppler at mitral inflow is displayed in Panel. There was a progressive shortening of the interval between E (early) and A (late) diastolic filling waves, followed by an absent A wave. A gradual shortening of the A-A wave interval was also noted. The interval between A wave and MR envelope remains constant. This typical pattern is consistent with Wenckebach phenomenon in sinoatrial (SA) exit block. SA exit block is due to failed propagation of pacemaker impulses beyond the SA node. In Type I second-degree SA block (Wenckebach), there is a progressive delay in the conduction from the SA node to the atrium until one impulse is completely blocked, leading to intermittent failure of atrial depolarization and ensuing absence of A wave in the Doppler inflow pattern. Moreover, the A-A wave interval is gradually decreased (i.e. the atrial rate accelerates) as the increment in the conduction delay from the SA node to the atrium becomes progressively smaller.

Heart rate characteristic based modelling of atrial fibrillatory rate using implanted cardiac monitor data

Objective. The objective of the present study is to investigate the feasibility of using heart rate characteristics to estimate atrial fibrillatory rate (AFR) in a cohort of atrial fibrillation (AF) patients continuously monitored with an implantable cardiac monitor. We will use a mixed model approach to investigate population effect and patient specific effects of heart rate characteristics on AFR, and will correct for the effect of previous ablations, episode duration, and onset date and time. Approach. The f-wave signals, from which AFR is estimated, were extracted using a QRST cancellation process of the AF episodes in a cohort of 99 patients (67% male; 57 ± 12 years) monitored for 9.2(0.2–24.3) months as median(min-max). The AFR from 2453 f-wave signals included in the analysis was estimated using a model-based approach. The association between AFR and heart rate characteristics, prior ablations, and episode-related features were modelled using fixed-effect and mixed-effect modelling approaches. Main results. The mixed-effect models had a better fit to the data than fixed-effect models showing h.c. of determination (R2 = 0.49 versus R2 = 0.04) when relating the variations of AFR to the heart rate features. However, when correcting for the other factors, the mixed-effect model showed the best fit (R2 = 0.04). AFR was found to be significantly affected by previous catheter ablations (p < 0.05), episode duration (p < 0.05), and irregularity of the RR interval series (p < 0.05). Significance. Mixed-effect models are more suitable for AFR modelling. AFR was shown to be faster in episodes with longer duration, less organized RR intervals and after several ablation procedures.

Left atrial strain rate: marker of hemodynamically significant coronary artery stenosis?

Aim: To assess the diagnostic value of left atrial deformation parameters during dobutamine stress echocardiography to predict significant coronary artery stenosis in patients with moderate pretest probability of coronary artery disease (CAD). Materials& methods: Rest and stress echocardiography were performed on 61 patients with a moderate and high probability of CAD. Based on presence of CAD patients were divided into pathological and nonpathological groups. Results: Early diastolic strain rate (LAe SR) was significantly lower among the pathological group at high dobutamine doses. LAe SR was evaluated with receiver operating characteristic curve and threshold prognostic value was set of -2.05 (sensitivity 78%, specificity 50%, area under the curve 0.638; p=0.026). Conclusion: Measuring LAe SR has predictive value and might be a helpful parameter in assessing ischemia.

Assessment of transmitral and left atrial appendage flow rate from cardiac 4D-CT

BackgroundCardiac time-resolved CT (4D-CT) acquisitions provide high quality anatomical images of the heart. However, some cardiac diseases require assessment of blood flow in the heart. Diastolic dysfunction, for instance, is diagnosed by measuring the flow through the mitral valve (MV), while in atrial fibrillation, the flow through the left atrial appendage (LAA) indicates the risk for thrombus formation. Accurate validated techniques to extract this information from 4D-CT have been lacking, however.MethodsTo measure the flow rate though the MV and the LAA from 4D-CT, we developed a motion tracking algorithm that performs a nonrigid deformation of the surface separating the blood pool from the myocardium. To improve the tracking of the LAA, this region was deformed separately from the left atrium and left ventricle. We compared the CT based flow with 4D flow and short axis MRI data from the same individual in 9 patients.ResultsFor the mitral valve flow, good agreement was found for the time span between the early and late diastolic peak flow (bias: <0.1 s). The ventricular stroke volume is similar compared to short-axis MRI (bias 3 ml). There are larger differences in the diastolic peak flow rates, with a larger bias for the early flow rate than the late flow rate. The peak LAA outflow rate measured with both modalities matches well (bias: −6 ml/s).ConclusionsOverall, the developed algorithm provides accurate tracking of dynamic cardiac geometries resulting in similar flow rates at the MV and LAA compared to 4D flow MRI.

Association of Left Atrial Strain With Ischemic Stroke Risk in Older Adults

The risk of ischemic stroke is higher among patients with left atrial (LA) enlargement. Left atrial strain (LAε) and LA strain rate (LASR) may indicate LA dysfunction when LA volumes are still normal. The association of LAε with incident ischemic stroke in the general population is not well established. To investigate whether LAε and LASR are associated with new-onset ischemic stroke among older adults. The Cardiovascular Abnormalities and Brain Lesions study was conducted from September 29, 2005, to July 6, 2010, to investigate cardiovascular factors associated with subclinical cerebrovascular disease. A total of 806 participants in the Northern Manhattan Study who were aged 55 years or older without history of prior stroke or atrial fibrillation (AF) were included, and annual follow-up telephone interviews were completed May 22, 2022. Statistical analysis was performed from June through November 2022. Left atrial strain and LASR were assessed by speckle-tracking echocardiography. Global peak positive longitudinal LAε and positive longitudinal LASR during ventricular systole, global peak negative longitudinal LASR during early ventricular diastole, and global peak negative longitudinal LASR during LA contraction were measured. Brain magnetic resonance imaging was used to detect silent brain infarcts and white matter hyperintensities at baseline. Risk analysis with cause-specific Cox proportional hazards regression modeling was used to assess the association of positive longitudinal LAε and positive longitudinal LASR with incident ischemic stroke, adjusting for other stroke risk factors, including incident AF. The study included 806 participants (501 women [62.2%]) with a mean (SD) age of 71.0 (9.2) years; 119 participants (14.8%) were Black, 567 (70.3%) were Hispanic, and 105 (13.0%) were White. During a mean (SD) follow-up of 10.9 (3.7) years, new-onset ischemic stroke occurred in 53 participants (6.6%); incident AF was observed in 103 participants (12.8%). Compared with individuals who did not develop ischemic stroke, participants with ischemic stroke had lower positive longitudinal LAε and negative longitudinal LASR at baseline. In multivariable analysis, the lowest (ie, closest to zero) vs all other quintiles of positive longitudinal LAε (adjusted hazard ratio [HR], 3.12; 95% CI, 1.56-6.24) and negative longitudinal LASR during LA contraction (HR, 2.89; 95% CI, 1.44-5.80) were associated with incident ischemic stroke, independent of left ventricular global longitudinal strain and incident AF. Among participants with a normal LA size, the lowest vs all other quintiles of positive longitudinal LAε (HR, 4.64; 95% CI, 1.55-13.89) and negative longitudinal LASR during LA contraction (HR, 11.02; 95% CI 3.51-34.62) remained independently associated with incident ischemic stroke. This cohort study suggests that reduced positive longitudinal LAε and negative longitudinal LASR are independently associated with ischemic stroke in older adults. Assessment of LAε and LASR by speckle-tracking echocardiography may improve stroke risk stratification in elderly individuals.

Remodeling in the AV block dog is essential for tolerating moderate treadmill activity.

A preclinical model standardized at different remodeling stages after AV block induction in awake state is suitable for the evaluation of improved cardiac devices. We studied exercise-induced cardiorespiratory parameters at three different timepoints after inducing AV block in dogs. Mongrel dogs (n=12) were placed on a treadmill with a 10% incline and performed a moderate exercise protocol (10-minute run at 6km/h). Dogs ran at sinus rhythm (SR), at two days (AVB2d, initiation of remodeling), three weeks (CAVB3) and six weeks (CAVB6, completed remodeling) after AV block. All dogs completed the exercise protocol at SR, CAVB3 and CAVB6, while 6/12 dogs at AVB2d failed to complete the exercise protocol. The atrial rate was higher at all AV block timepoints (126±20 to 141±19bpm at rest and 221±10 to 231±13bpm during exercise) compared to SR (100±29bpm at rest and 162±28bpm during exercise, p<0.05). Upon exercise, stroke volume increased from 66±15ml at SR, to 96±21ml at AVB2d (p<0.05), 91±13ml at CAVB3 (p<0.05) and 85±24ml at CAVB6 but failed to compensate for the AV block-induced bradycardia. Therefore, cardiac output was lower after AV block compared to SR. Exercising dogs at AVB2d showed most arrhythmic events, lowest VO2, and signs of desaturation and acidification in venous blood. Dogs with limited remodeling after AV block have a reduced exercise tolerance, which is reflected in changes in cardiorespiratory parameters.

Investigation on the positive chronotropic action of 6-nitrodopamine in the rat isolated atria.

6-Nitrodopamine (6-ND) is released from rat isolated atria being 100 times more potent than noradrenaline and adrenaline, and 10,000 times more potent than dopamine as a positive chronotropic agent. The present study aimed to investigate the interactions of 6-ND with the classical catecholamines, phosphodiesterase (PDE)-3 and PDE4, and the protein kinase A in rat isolated atria. Atrial incubation with 1 pM of dopamine, noradrenaline, or adrenaline had no effect on atrial frequency. Similar results were observed when the atria were incubated with 0.01 pM of 6-ND. However, co-incubation of 6-ND (0.01 pM) with dopamine, noradrenaline, or adrenaline (1 pM each) resulted in significant increases in atrial rate, which persisted over 30 min after washout of the agonists. The increased atrial frequency induced by co-incubation of 6-ND with the catecholamines was significantly reduced by the voltage-gated sodium channel blocker tetrodotoxin (1 µM, 30 min), indicating that the positive chronotropic effect of 6-ND is due in part to activation of nerve terminals. Pre-treatment of the animals with reserpine had no effect on the positive chronotropic effect induced by dopamine, noradrenaline, or adrenaline; however, reserpine markedly reduced the 6-ND (1 pM)-induced positive chronotropic effect. Incubation of the rat isolated atria with the protein kinase A inhibitor H-89 (1 µM, 30 min) abolished the increased atrial frequency induced by dopamine, noradrenaline, and adrenaline, but only attenuated the increases induced by 6-ND. 6-ND induces catecholamine release from adrenergic terminals and increases atrial frequency independently of PKA activation.

Clinical characteristics and outcomes of atrial flutter in neonates.

Atrial flutter is an uncommon arrhythmia that can cause severe morbidity, including heart failure and even death in refractory cases. This study investigated the clinical characteristics, treatment, and long-term outcomes of patients with neonatal atrial flutter and its association with heart failure. We retrospectively reviewed atrial flutter cases observed in our center between 1999 and 2021 and analyzed the clinical characteristics, treatment, and recurrence according to the presence of heart failure. The study comprised 15 patients with atrial flutter, with median bodyweight and gestational age of 2.7 kg, 37+4 weeks, respectively. Twelve patients were diagnosed with atrial flutter on the first day of life. The median atrial and ventricular rates were 440/min, 220/min, respectively. Four patients exhibited congestive heart failure. Episodic recurrence was noted in five patients and occurred at a higher rate in patients with congestive heart failure (p = 0.004). Antiarrhythmic drugs for maintenance treatment were administered more often in patients with heart failure (p = 0.011). Initial treatment included direct current cardioversion (n = 9), digoxin (n = 4), and observation (n = 2). Four patients treated with cardioversion experienced recurrence during the neonatal period, and none of those treated with digoxin experienced recurrence. The median follow-up duration was 7 years, during which no atrial flutter recurrence was evident. Neonates with congestive heart failure had a higher recurrence of atrial flutter. Direct current cardioversion is the most reliable treatment for neonatal atrial flutter, whereas digoxin may be a viable treatment option in refractory and recurrent cases.

The Relation between Atrial Fibrillation Cardioversion Success Rate with Vitamin D Level in Patients Underwent Elective Cardioversion in King Abdulaziz Cardiac Center, King Abdulaziz Medical City for National Guards, Riyadh Saudi Arabia.

To investigate the relation between serum Vitamin D (Vit-D) levels and the success rate of cardioversion for atrial fibrillation (AF). To examine the association between Vit-D level and successful cardioversion. This study also describes the general characteristics of patients with successful cardioversion. In this retrospective study, patients with AF who were treated using electrical cardioversion at King Abdulaziz Cardiovascular Center (KACC) between 2010 and 2021 were included. The information on demographic and clinical characteristics as well as outcome variables was collected. Of 100 patients who were admitted to KACC during the study period, 63% were females and 9% were diagnosed with Vit-D deficiency. Furthermore, 66% of patients had successful cardioversion. Moreover, no significant difference in Vit-D deficiency was observed between patients who had successful cardioversion and those with unsuccessful outcomes (P = 0.485). There is no association between serum Vit-D levels and the success rate of cardioversion in patients with AF. However, further studies are needed for more conclusive evidence.

Vericiguat reduces electrical and structural remodeling in a rabbit model of atrial fibrillation.

Purpose: The molecular etiology of atrial fibrillation (AF) and its treatment are poorly understood. AF involves both electrical and structural features. Vericiguat can ameliorate cardiac remodeling in heart failure. The effects of vericiguat on AF, however, are unclear. Here, the actions of vericiguat on atrial structural and electrical remodeling in AF and its possible mechanisms were investigated. Methods and Results: Thirty-six rabbits were randomly allocated to four groups, namely, sham, RAP (pacing with 600 beats/min over three weeks), vericiguat-treated (three weeks' pacing plus daily oral dose of 1.5 mg/kg of vericiguat), and vericiguat-treated only. HL-1 cells received rapid pacing with or without vericiguat. Parameters including electrophysiology, echocardiography, histology, Ca2+ levels, and ICaL density, as well as levels of TRPC6, CaN, NFAT4, p-NFAT4, Cav1.2, collagen I, collagen III, and ST2 were measured. Significant changes of above proteins expression level, circulating biochemical indices, Ca2+ concentrations, and ICaL density in both animals and cell models, these effects were significantly restored by vericiguat. Vericiguat also reversed the enlarged atrium and significantly reduced myocardial fibrosis, together with preventing reduced atrial effective refractory periods (AERPs) and AF induction rate. Conclusion: Vericiguat thus ameliorated AF-associated structural and electrical remodeling. These findings suggest the potential of vericiguat for treating AF.

Prediction of Clinical Atrial Fibrillation by Cardiac Implantable Electronic Device detected Atrial High Rate Episodes

Prediction of Clinical Atrial Fibrillation by Cardiac Implantable Electronic Device detected Atrial High Rate Episodes

772 SCREENING FOR ANDERSON-FABRY DISEASE IN RELATIVELY YOUNG PATIENTS WITH UNEXPLAINED CONDUCTION DISORDERS REQUIRING PACEMAKER IMPLANTATION

Abstract Background Anderson-Fabry Disease (AFD, OMIM 301500) is a rare X-linked lysosomal storage disorder caused by GLA gene mutation resulting in a deficit or absent activity of the α-galactosidase A enzyme (α-Gal A). This deficiency involves the impossibility of cleavage of glycophospholipids, resulting in an intralisosomal accumulation of them in different tissues. Due to an incidence of 1 in 80000, AFD is considered the second most common glycosphingolipid storage disorder after Gaucher disease. Cardiac manifestations include left ventricular hypertrophy (LVH) and arrhythmias. The rate of pacemaker implantation (PMI) in AFD has been described to be 25 times higher than in the general population, and the requirement of PMI has been reported to be as high as 8% in some AFD series. In this context, the presence of conduction abnormalities in young patients may suggest an undiagnosed AFD.1 Therefore, early diagnosis is important in AFD because appropriate therapies seem to be more effective when initiated promptly. Purpose Our aim is to detect AFD among relatively patients with unexplained conduction disturbances requiring PMI, not submitted to newborn screening. Methods Among 650 patients afferent to our ambulatory for routinary pacemaker follow-up, we considered a selected population with diagnosis of sinus node dysfunction or atrioventricular block (confirmed by atrial pacing rate ≥ 60% or ventricular pacing percentage ≥ 80%) and an age, at the time of PMI, ranging between ≥40 and ≤70 years old. The exclusion criteria were: patients with previous myocardial infarction; patient whit known cardiac disease (such as hypertrophic cardiomyopathy); patients who underwent cardiac surgery and patients with extracardiac disease with cardiac involvement such as autoimmune disorders. For this cohort of 26 adult patients (13 males; 13 females; mean age 63 ± 7 years) a prospective screening study for AFD was performed. After clinical evaluation, transthoracic echocardiography (analyzing signs of left ventricular hypertrophy) and pacemaker check, a dried blood spot sampled in filter paper was analyzed. This filter paper assay was performed in male patients in order to evaluate the α-Galactosidase A enzyme activity through the detection of Fabry disease biomarkers; only in the case of abnormal values, genetic investigation was performed. In female patients, the analysis was exclusively genetic. Results The analyses revealed 58% (15/26) of patients affected by mild LVH (IVS diameter ranging from 11 to 15 mm). No patient had severe LVH (IVS diameter ≥15 mm) or moderate-severe renal dysfunction (more than stage 3B, GFR below than 30-44 mL/min). In the restrict cohort considered, we found one 69 yo female patient with heterozygosis GLA pathogenic mutation, NM_000169.2:c.638A&amp;gt;C p.(Lys213Thr). She had normal value of liso-Gb3 1,1 ng/ml (n.v. ≤ 1,8 ng/ml). She had mild LVH (IVS diameter 12 mm) and no renal dysfunction. Familiar screening was programmed. Conclusion In a highly selected sample of relatively young patients with conduction disturbances requiring pacemaker implantation, a female patient with genetic mutation causing AFD has been identified. Therefore, it seems that screening efforts should be increased in this patient population. 1 Hemelsoet D, De Keyser J, Van Heuverswyn F et al. Screening for Fabry Disease in Male Patients With Arrhythmia Requiring a Pacemaker or an Implantable Cardioverter-Defibrillator. Circulation. 2021 Feb 23;143(8):872-874. doi: 10.1161/CIRCULATIONAHA.120.051400.

Novel findings of an old algorithm: PVC response "Atrial Pace'' initiates atrial arrhythmias in Abbott ICD and CRT-D devices.

Many algorithms have been developed to ensure the safety and accuracy of cardiac implantable electric devices (CIED). A specific algorithm designed to prevent pacemaker induced tachycardia (PMT) after a premature ventricular complex (PVC response) is available in all Abbott (former St. Jude Medical) CIED. However, a few case reports suggest that this algorithm may be proarrhythmic when programmed to Atrial Pace (A-Pace on PVC). We analyzed the data of all (n=333) Abbot implantable cardioverter defibrillator (ICD) and cardiac resynchronization defibrillator (CRT-D) devices followed remote using the Merlin.net Patient Care Network in our institute in 2020. Status of the PVC response algorithm A-Pace on PVC or Off was collected, and all atrial mode switch (AMS) episodes longer than 30 s were thoroughly evaluated. Data on clinical characteristics of the patients was collect from the electronic patient records. A total of 173 patients had A-Pace on PVC and twenty-five of them (14%) had at least one atrial high rate episode (AHRE) >30 s (AHRE) triggered by the action of this algorithm. The median PVC count was higher in patients who had algorithm triggered AHRE than in those with no algorithm-triggered AHRE (1.7% [IQR 0-3.2] vs. 0% [IQR 0-1.1], p<.0001). The major clinical characteristics were comparable in the two groups. The A-Pace on PVC setting was frequently used in our patients. Our study shows that a considerable number of patients had at least one AHRE triggered by the algorithm. The use of this algorithm should be carefully reconsidered.

Effect of angiotensin receptor-neprilysin inhibitor on atrial electrical instability in atrial fibrillation.

Around 33.5 million patients suffered from atrial fibrillation (AF), causing complications and increasing mortality and disability rate. Upstream treatment for AF is getting more popular in clinical practice in recent years. The angiotensin receptor-neprilysin inhibitor (ARNI) is one of the potential treatment options. Our study aimed to investigate the effect of ARNI on atrial electrical instability and structural remodeling in AF. Our research consisted of two parts - a retrospective real-world clinical study and an animal experiment on calmness to verify the retrospective founding. In the retrospective study, we reviewed all patients (n = 110) who had undergone the first AF ablation from 1 August 2018 to 1 March 2022. Patients with ARNI (n = 36) or angiotensin II receptor antagonist (ARB) (n = 35) treatment were enrolled. Their clinical data, ultrasound cardiogram (UCG) and Holter parameters were collected before radiofrequency catheter ablation (RFCA) as baseline and at 24-week follow-up. Univariate and multivariate logistic regression analysis were performed. In the animal experiment, we established an AF model (n = 18) on canines by rapid atrial pacing. After the successful procedure of pacing, all the 15 alive beagles were equally and randomly assigned to three groups (n = 5 each): Control group, ARB group, and ARNI group. UCG was performed before the pacing as baseline. Physiological biopsy, UCG, and electrophysiological study (EPS) were performed at 8-week. Clinical data showed that the atrial arrhythmia rate at 24-week was significantly lower in ARNI group compared to ARB group (P < 0.01), and ARNI was independently associated with a lower atrial arrhythmia rate (P < 0.05) at 24-week in multivariate regression logistic analysis. In the animal experiment, ARNI group had a higher atrial electrical stability score and a shorter AF duration in the EPS compared to Control and ARB group (P < 0.05). In the left atrium voltage mapping, ARNI group showed less low voltage and disordered zone compared to Control and ARB group. Compared to Control group, right atrium diameter (RAD), left ventricle end-diastolic volume index (LVEDVI), E/A, and E/E' were lower in ARNI group (P < 0.05) at the 8-weeks follow-up, while left atrium ejection fraction (LAEF) and left ventricle ejection fraction (LVEF) were higher (P < 0.01). Compared to ARB group, LVEF was higher in ARNI group at the 8-week follow-up (P < 0.05). ARB and ARNI group had a lower ratio of fibrotic lesions in the left atrium tissues compared to Control group (P < 0.01), but no difference was found between the ARB and the ARNI group. ARNI could reduce atrial electrical instability in AF in comparison with ARB in both retrospective study and animal experiment.

Effects of ranolazine on various outcomes in patients with stable angina: an updated meta-analysis

ObjectiveWe determined the effect of ranolazine vs. placebo in angina patients on 1) selective measures of the ischemic burden, 2) cardiovascular outcomes, including atrial fibrillation incidence, 3) the in-treatment glycohemoglobin levels and the permanent discontinuations because of side effects, and 4) the achieved between-arms blood pressure and heart rate difference. MethodsPubMed and Cochrane Collaboration Library databases were searched for eligible trials until end of September 2020. Trial quality was assessed by the Rob2 tool. Risk ratios or achieved mean differences during follow-up and 95% confidence interval (CI) of categorical or continuous outcomes, respectively, were calculated (random-effects model). The relationship between discontinuation rates and ranolazine's mean dose was investigated by meta-regression analysis. ResultsWe selected 18 trials (n = 12,995 patients in patients with macro or microvascular coronary heart disease. Achieved blood pressure and heart rate at rest were not different between randomized arms. Ranolazine administration compared to placebo was associated with an increase of 1) total exercise duration by 30 seconds (95% CI, 18-42), 2) time to 1 mm ST-segment depression by 44 seconds (95% CI, 30-54), and 3) time to angina onset by 40 seconds (95% CI, 30-54). On average, the incidence of atrial fibrillation was reduced by 25% following ranolazine treatment compared to placebo, while glycohemoglobin showed a mean decrease of 0.4% (95% CI, 0.3-0.5%). DiscussionRanolazine remains an effective anti-ischemic drug, increases the angina-free exercise duration, delays the onset of ST-segment depression. The beneficial effects of ranolazine are extended to atrial fibrillation reduction rates and better glycemic control.

The prognostic value of the left atrial strain rate determined using cardiovascular magnetic resonance feature tracking imaging in patients with severe idiopathic dilated cardiomyopathy.

Left atrial strain rate (LASR) is rarely used as an indicator of cardiovascular disorder prognosis in dilated cardiomyopathy (DCM). In the present study, we aimed to explore the prognostic value of the LASR in patients with severe idiopathic DCM [left ventricle ejection fraction (LVEF) <35%] using cardiac magnetic resonance feature tracking (CMR-FT). A retrospective cohort study was performed. At the time of enrollment, patients who underwent cardiovascular magnetic resonance (CMR) imaging were selected for the study. Left atrium (LA) strain rate was measured in patients with severe idiopathic DCM from four-chamber and two-chamber views using a 3.0-T CMR scanner. The study endpoint was defined as a combination of all-cause death, implantable cardioverter-defibrillator (ICD), hospitalization due to cardiac failure, and heart transplantation. Cox model analyses were used to assess the statistical significance of the risk factors. Fifty-eight patients with a confirmed diagnosis of severe idiopathic DCM were ultimately included in the analysis [mean age of 46 years; 41 (73%) men]. The median follow-up was 43 months (13-72 months). Adverse cardiovascular events occurred in 29 patients: all-cause death occurred in 15 participants (25.8%), ICD was performed in 5 participants (8.6%), heart failure hospitalization occurred in 8 participants (13.8%), and 1 participant (1.7%) underwent heart transplantation. From univariate analysis, the left atrium reservoir strain rate (LASRs) [HR 0.12; 95% CI (0.02, 0.55), P=0.007] and the left atrium booster pump strain rate (LASRa) [HR 3.21; 95% CI (1.08, 9.58), P=0.036] significantly predicted the association with cardiovascular events. In model 1 after adjusting for basic cardiovascular risk factors, including age, hypertension, diabetes mellitus, and N-terminal pro-brain natriuretic peptide (NT-proBNP), the LASRs [HR 0.12, 95% CI (0.02, 0.58), P=0.009] was assessed. The mitral valve regurgitation, LA maximum volume index, and LA diastatic volume index were added in model 2 based on model 1. LASRs [HR 0.13, 95% CI (0.02. 0.82) P=0.030] was the independent prediction factor after adjustment for model 1 and model 2. The LASRs had a good prognostic value with an area under the curve of receiver operating characteristic of 0.697 (0.617, 0.777) at 1 year, 0.716 (0.643, 0.788) at 3 years, 0.716 (0.651, 0.798) at 5 years and 0.703 (0.597, 0.809) at 7 years. LA reservoir strain rate and active strain rate were powerful prognostic markers. The LASRs by MRI-FT provided independent prognostic value in patients with severe idiopathic DCM.