Development Of Paroxysmal Atrial Fibrillation Research Articles

Long-term follow-up of single-chamber atrial pacing - system upgrade and wenckebach block point behavior: potential implications for leadless AAI pacing?

Abstract Introduction Until recently leadless pacemakers (PM) did not support atrial pacing. A novel dual chamber leadless PM system now provides treatment option for a wide range of indications. Single-chamber atrial stimulation (AAI) for the treatment of symptomatic sick sinus syndrome (SSS) is scarcely used due to concerns about the potential development of atrioventricular block (AVB) and development of paroxysmal atrial fibrillation (AF). Long-term follow-up data of AAI-PM is however scarce. Little is known about the role of serial Wenckebach block point (WBP) measurements in AAI-PM patients for risk stratification. Purpose To assess the incidence of dual chamber upgrade of patients treated with AAI-PM for SSS during long-term follow-up and to investigate the role of serial WBP measurements for risk stratification. Methods Prospectively enrolled patients undergoing implantation of an AAI-PM between October 2002 and December 2023. WBP was measured at implantation and serially during follow up. Results We included a total of 178 patients, of which 58% were female and the median age at implantation was 78 [IQR 71 – 83] years. The median follow-up duration was 6.5 [IQR 2.0 – 9.7] years. 24 patients (13.5%) received a system upgrade to DDD including 3 patients (1.7%) with a mode change to ventricular pacing only (VVI). Adjusted for years of follow-up the upgrade rate was 2.1% per year. Median time to system upgrade was 5.2 [IQR 1.6 – 8.7] years. Reasons for system upgrade were high-degree AVB (38%), low WBP (17%), atrial arrhythmias (33%), unclear syncope (8%) and infection (4%). Median WBP at implantation was 130 [120 – 140] bpm, showing a significant decline over time in the upgrade-group with 105 [95 – 130] bpm compared to the rest of the cohort with 130 [120-130] bpm (p = 0.009). A decline in WBP >20 bpm was found in 17.9% patients and a decline of 10-20 bpm in 33.7% of patients. New-onset atrial arrythmias were found in 36 patients (20%), 29% in the upgrade group and 19% in the rest of the cohort (p = 0.3). Neither age at implantation, sex, WBP at implantation, nor atrial arrhythmia prior to implantation were predictive for the need of a future system upgrade. Conclusion In this cohort of patients undergoing AAI-PM implantation for SSS, a system upgrade was required in 2% per year. The WBP remained stable in 48% of patients. Therefore, AAI-PM due to SSS emerges as a judicious and secure therapeutic modality, warranting increased consideration in the light of new treatment options for leadless pacing.

Abstract 18768: Diagnosis of Occult Atrial Fibrillation in Patients With Embolic Stroke of an Undetermined Source Based on Left Atrial Strain

Introduction and Hypothesis: A late electrocardiographic evaluation of patients with embolic stroke of an undetermined source (ESUS) can show atrial fibrillation as a potential cause of embolic stroke. Existing literature has highlighted that left atrial dysfunction can lead to the development of paroxysmal atrial fibrillation (PAF) and subsequent embolism. Our study sought to evaluate the diagnosis of occult atrial fibrillation in patients with embolic stroke of an undetermined source based on abnormalities in the left atrial strain. Methods: 230 patients were included in our multi-center, observational study with the mean age as 56.4 years and 26% females. We followed up on these patients for the occurrence of paroxysmal atrial fibrillation and recurrent ischemic stroke. Trans thoracic echocardiography (TTE) was done, and images were subsequently analyzed for spackle tracing deformation patterns. Primary and secondary outcomes included plotting these atrial strain values against PAF and recurrent ischemia, respectively. Results: 198 patients completed the study. Patients with newly diagnosed PAF had more abnormal left atrial reservoir strain (LASr; 27.3% ± 12.2%, P<0.05) and left atrial conduit strain (LAScd; -13.7% ± 6.2%, P<0.05) compared with patients who had normal rhythm. Multivariable logistic regression analysis showed that LAScd was associated with occult PAF (adjusted odds ratio [aOR] = 1.212, 95% CI, 1.043-1.314, P<0.05) and the composite outcome of AF and recurrent ischemic stroke (OR = 1.146, 95% CI, 1.023-1.185, P<0.05). Conclusions: Our study concluded that abnormal left atrial strain is associated with the detection of occult AF in patients admitted with embolic stroke of undetermined origin. Early detection of etiology by determining left atrial strain can lead to better prognosis and good clinical outcomes.

ECHOCARDIOGRAPHIC PREDICTORS OF ADVERSE CLINICAL EVENTS IN HEART FAILURE WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTION IN COMBINATION WITH OBSTRUCTIVE SLEEP APNEA

HighlightsRepeated hospitalizations occupy a special place in adverse clinical events in heart failure, currently representing one of the most powerful predictors of adverse outcomes in this group of patients. Echocardiographic parameters such as longitudinal myocardial deformation, displacement in the annulus of the tricuspid valve, and left atrial volume index can serve as predictors of hospitalization for cardiovascular diseases in patients with heart failure with preserved ejection fraction and obstructive sleep apnea. Abstract Aim. To study the prognostic role of individual echocardiographic parameters in heart failure with preserved ejection fraction (HFpEF) in patients with arterial hypertension and obstructive sleep apnea (OSA).Methods. The study included 59 men with hypertension and OSA (apnea/hypopnea index >15 per hour). At baseline all patients underwent a sleep study and echocardiography with an additional assessment of the global longitudinal strain (GLS). Upon inclusion in the study and after 12 months of follow-up, a 6-minute walk test was performed. After 12 months, the clinical course of the disease was retrospectively assessed. The criteria for an adverse clinical course were episodes of hospitalization for cardiovascular diseases, the development of paroxysmal atrial fibrillation or high-grade ventricular arrhythmias (III–V class according to Ryan), worsening of heart failure with a transition to a higher functional class according to NYHA.Results. Significant differences were found in several echocardiographic parameters between the groups of patients with and without hospitalizations within 12 months of follow-up: tricuspid annular plane systolic excursion (TAPSE) (p = 0.017), GLS (p = 0.005), left atrial volume index (LAVI) (p = 0.032). According to the regression analysis results, TAPSE, GLS and left ventricular ejection fraction make a statistically significant contribution to the probability of hospitalizations among the evaluated echocardiographic predictors.Conclusion. The results of the study allow us to consider certain echocardiographic parameters, in particular GLS, TAPSE and LAVI, as predictors of hospitalizations in patients with HFpEF and OSA.

Steady-state and transient effects of SK channel block and adrenergic stimulation to counteract acetylcholine-induced arrhythmogenic effects in the human atria: A computational study

Hyperactivity of the parasympathetic nervous system has been linked to the development of paroxysmal atrial fibrillation (AF). The parasympathetic neurotransmitter acetylcholine (ACh) causes a reduction in action potential (AP) duration (APD) and an increase in resting membrane potential (RMP), both of which contribute to enhance the risk for reentry. Research suggests that small-conductance calcium activated potassium (SK) channels may be an effective target for treating AF. Therapies targeting the autonomic nervous system, either alone or in combination with other drugs, have been explored and have been shown to decrease the incidence of atrial arrhythmias. This study uses computational modeling and simulation to examine the impact of SK channel block (SKb) and β-adrenergic stimulation through Isoproterenol (Iso) on countering the negative effects of cholinergic activity in human atrial cell and 2D tissue models. The steady-state effects of Iso and/or SKb on AP shape, APD at 90% repolarization (APD90) and RMP were evaluated. The ability to terminate stable rotational activity in cholinergically-stimulated 2D tissue models of AF was also investigated. A range of SKb and Iso application kinetics, which reflect varying drug binding rates, were taken into consideration. The results showed that SKb alone prolonged APD90 and was able to stop sustained rotors in the presence of ACh concentrations up to 0.01 μM. Iso terminated rotors under all tested ACh concentrations, but resulted in highly-variable steady-state outcomes depending on baseline AP morphology. Importantly, the combination of SKb and Iso resulted in greater APD90 prolongation and showed promising anti-arrhythmic potential by stopping stable rotors and preventing re-inducibility.

ПРОГНОСТИЧЕСКАЯ РОЛЬ ПАРАМЕТРОВ ДЫХАНИЯ В РАЗВИТИИ АРИТМИЙ У ПАЦИЕНТОВ С СИНДРОМОМ ОБСТРУКТИВНОГО НОЧНОГО АПНОЭ И ХРОНИЧЕСКОЙ СЕРДЕЧНОЙ НЕДОСТАТОЧНОСТЬЮ

Abstract. Obstructive sleep apnea syndrome (OSAS) is increasingly being considered as a factor associated with the development of nocturnal arrhythmias, as well as an increased risk of sudden cardiac death. The prevalence of OSA reaches 5-7% in the adult population. The prognostic role of pathological breathing patterns has not been sufficiently investigated, and therefore further study of the pathogenesis of arrhythmias for the subsequent intensification of therapeutic measures is promising. Aim of the Research. To study the prognostic significance of individual breathing parameters in different sleep phases for the development of atrial fibrillation and ventricular arrhythmias in patients with obstructive sleep apnea syndrome (OSAS) and chronic heart failure (CHF) with preserved ejection fraction (EF). Materials and methods. 86 men with moderate and severe OSAS (with an apnea/hypopnea index (AHI) >15 per hour) were examined. To diagnose OSAS, all patients underwent a polysomnographic study of night sleep. The severity of obstructive respiratory disorders during sleep was assessed by the apnea/hypopnea index for the total period of sleeping. Using polysomnography, we additionally investigated the following parameters of respiratory disturbances during the night sleep period: index of obstructive apnea/hypopnea selectively in REM sleep (AHIobsREM); index of respiratory distress syndrome for the entire period of sleep (IRDS); index of respiratory distress syndrome in the REM sleep phase (IRDS REM); average saturation per night; desaturation index for the total period of sleep; desaturation index in REM sleep. The observation period was 12 months, during which the presence of atrial fibrillation paroxysms lasting more than 30 s and the development of high-grade ventricular arrhythmias (III-V class according to Ryan) were assessed. Results. In the course of the study, a number of breathing parameters during the night time sleep (IAHobs, IAHobsREM, IRDS, IRDS REM) significantly correlated with the development of the studied cardiac arrhythmias. The most significant prognostic role has been stated for obstructive sleep apnea registered in the REM sleep phase. Conclusion. Breathing parameters during nighttime sleeping (IAHobs, IAHobs REM, IRDS, IRDS REM), which characterize the severity of OSAS are independent predictors of the development of paroxysmal atrial fibrillation and high-grade ventricular extrasystole in patients with OSAS and CHF with preserved EF. The results obtained make it possible to use these sleep parameters in the future in stratifying the risk of arrhythmias and determining treatment tactics in this cohort of patients.

THE PROGNOSIS OF DEVELOPMENT OF THE PAROXYSM OF ATRIAL FIBRILLATION IN PATIENTS WITH POST-INFARCTION CARDIOSCLEROSIS

Aim . Create an algorithm predicting the risk of development of paroxysmal atrial fibrillation in patients with coronary heart disease on the background of post-infarction cardiosclerosis (PICS). Material and Methods. There was conducted the deep analysis of a number of laboratory and functional indicators (indicators of peroxidation of proteins, lipids, antioxidant protection and skin microcirculation) at 85 patients with atrial fibrillation (AF). All patients were divided into 4 groups: patients with paroxysmal and chronic AF without PICS (27 people), patients with paroxysmal and chronic AF with PICS (12), patients with permanent AF without PICS (26) and patients with permanent form of AF with PICS (20). Results. There was created the mathematical model to predict the development of atrial fibrillation in patients with PICS with calculation of the odds ratio of atrial fibrillation. Methods of correlation and factor analysis revealed the greatest value for the prognosis of paroxysmal atrial fibrillation in patients with PICS two factors: the total level of deep oxidation products of protein and an indicator of microcirculation by laser Doppler flowmetry. The diagnostic sensitivity of the developed prognostic model was 86%, specificity of the test – 94%, the diagnostic efficiency of the test – 90%. Conclusion. The study has been proven clinical diagnostic and prognostic value of a comprehensive study of indicators of oxidation-reduction reactions, and the microcirculation indices in combination with standard laboratory and instrumental investigations in patients with AF. The developed mathematical model allows to predict the development of atrial fibrillation in patients with PICS.

Detection of Occult Paroxysmal Atrial Fibrillation in Stroke Patients Using High Resolution Electrocardiography

Background: Paroxysmal atrial fibrillation (AF) is highly prevalent in patients with ischemic stroke, but the diagnosis is often difficult. Methods: This study consisted of 61 stroke patients in sinus rhythm without a history of paroxysmal AF. All patients underwent P-wave signal-averaged electrocardiography (P-SAECG), echocardiography, 24-hour Holter monitoring, and measurement of plasma B-type natriuretic peptide (BNP) concentrations at admission. Results: An abnormal P-SAECG was found in 33 of 61 stroke patients. In the follow-up period of 11±3 months, paroxysmal AF developed in 19 patients (AF group). The remaining 42 patients were divided into non-AF group. An abnormal P-SAECG and frequent premature atrial contractions (PACs, 100 or more/24 hour) were detected more frequently in patients with AF group than non-AF group (89.5% vs 35.7%; p<0.001, 84.2% vs 26.2%; p<0.001, respectively). However, there were no significant differences in age, left atrial dimension, BNP concentrations between both groups. Cox proportional hazards analysis revealed that an abnormal P-SAECG (hazard ratio 21.3; p=0.003) and frequent PACs (hazard ratio 4.6; p=0.046) had significant correlation to the development of paroxysmal AF. Conclusions: An abnormal P-SAECG and frequent PACs may be novel predictors of paroxysmal AF in stroke patients. P-SAECG should be considered in stroke of undetermined etiology.

A novel cardiac myosin-binding protein C S297X mutation in hypertrophic cardiomyopathy

Mutations in the cardiac myosin-binding protein C gene (MYBPC3) have been reported to be associated with delayed expression of hypertrophic cardiomyopathy (HCM) and a relatively good prognosis. The aim of this study was to evaluate clinical manifestations in patients with familial HCM caused by a novel nonsense mutation, S297X, in MYBPC3. We analyzed the sarcomere protein genes in 93 probands with HCM. The nonsense mutation S297X in MYBPC3 was present in nine subjects from two unrelated families. Eight of those nine subjects with this mutation were found to be phenotype-positive and the remaining individual was not affected phenotypically. The age range at diagnosis was 9-75 years. There was no family history of sudden death in either family. At presentation, there were various left ventricular hypertrophy (LVH) patterns, including Maron type III hypertrophy from the LV base to apex, hypertrophy confined to the anterolateral wall at the basal LV wall. Two patients showed a significant LV outflow tract gradient and one patient showed intra-right-ventricular obstruction. During follow-up, one patient was repeatedly hospitalized for the treatment of heart failure after development of paroxysmal atrial fibrillation at the age of 86 years and the remaining eight subjects were in relatively stable condition and did not require hospitalization for the treatment of HCM-related events. The novel mutation S297X in MYBPC3 causes HCM in a broad range of ages and heterogeneous clinical manifestations, though the clinical course in patients with this mutation seems to be benign.

The Influence of the Amount of Ultrafiltration in Chronic Hemodialysis on P Wave Dispersion

Objective. Paroxysmal atrial fibrillation (AF) observed in patients undergoing chronic hemodialysis program with higher rates is an important morbidity and mortality cause that negatively influences the hemodynamics and leads to thromboembolic complications. It is known that P wave dispersion (PWD) facilitating the development of paroxysmal atrial fibrillation is increasing during intradialytic process. This study researched the influence of various amounts of ultrafiltration that applied in the various hemodialysis sessions in the same patient cohort on PWD. Materials and Methods. 25 patients in a chronic hemodialysis program undergoing four hours bicarbonate hemodialysis three times a week were included in the study. The patient cohort was divided into four groups regarding the amount of ultrafiltration (UF) performed during a four-hour standard hemodialysis session as following: UF up to 1 liter, UF of 1–2 liters, UF of 2–3 liters, and UF of 3–4 liters. Notes were kept until each patient had been included once into each group regarding the amount of ultrafiltration performed parallel to intradialytic weight gain in different hemodialysis session. A 12-lead ECG was taken from the patients immediately before the hemodialysis and within 20 minutes after completion of the session, and maximum P wave duration (Pmax), minimum P wave duration (Pmin) and PWD values (i.e., the difference between Pmax and Pmin) were measured. The inter-group data was assessed with a one-way ANOVA, and the within-group assessments were performed with paired samples test. Mann Whitney U test was used for the evaluations performed according to the presence of diabetes. Findings. The mean age of 25 patients (15 male and 10 female) was 62.7 ± 20.2 (range: 21–89). PWD after UF was decreased significantly in group 1 (56.12 ± 15.26 vs. 46.60 ± 18.45 ms, p = 0.018) and were increased in groups with UF more than 1 liter: group 2 (39.68 ± 21.26 vs. 47.12 ± 21.20 ms, p = 0.020), group 3 (41.60 ± 23.99 vs. 65.92 ± 31.04 ms, p = 0.001), and group 4 (17.52 ± 14.67 vs. 26.80 ± 15.52 ms, p = 0.007). Furthermore, while PWD before UF was significantly higher in a diabetic group compared to a nondiabetic group (68.85 ± 10.44 vs. 51.16 ± 14.06 ms, p = 0.007), it was seen that PWD difference had disappeared after UF application (57.14 ± 17.99 vs. 42.50 ± 17.40 ms, p = 0.065). Conclusion. UF application of more than 1 liter during hemodialysis session increases the PWD value significantly. Hypervolemia exceeding 1 liter between two dialysis sessions should be avoided in all patient groups, especially in diabetics, and an effective UF planning should be arranged because of a decrease in PWD values with UF observed in diabetics.

P-054 different predictor indexes for the development of paroxysmal atrial fibrillation among hypertensive population

P-054 different predictor indexes for the development of paroxysmal atrial fibrillation among hypertensive population

P-054 different predictor indexes for the development of paroxysmal atrial fibrillation among hypertensive population

P-054 different predictor indexes for the development of paroxysmal atrial fibrillation among hypertensive population

C-reactive protein and paroxysmal atrial fibrillation: evidence of the implication of an inflammatory process in paroxysmal atrial fibrillation

Background — Detection of inflammation is best achieved by measurements of C-reactive protein (CRP).We investigated whether inflammation might promote the development of paroxysmal atrial fibrillation (PAF), and whether high levels of CRP are associated with an increased risk of PAF.Methods — We assessed the levels of CRP and other risk factors in patients with PAF of recent onset (<24 h), compared with age and sex matched controls with the same risk factors who had normal sinus rhythm. Patients with thyrotoxicosis, mitral stenosis, pulmonary emboli or pericarditis were excluded. Fifty patients with PAF and 50 control subjects were finally included. All patients received amiodarone (2.7 g over 24 hours).Results — Conversion to normal sinus rhythm was achieved within 24 h in 40 patients. CRP levels were higher (P<0.001) in the PAF group (median = 0.80, min = 0.00, max = 5.90 mg/dl) compared with controls (median = 0.04, min = 0.00, max = 0.48 mg/dl). In the PAF group CRP levels were higher (P<0.001) for patients who failed to be cardioverted (median = 2.12, min = 0.80, max = 5.90 mg/dl) compared to cardiovertors. Nevertheless, CRP levels in patients who underwent successful cardioversion (median = 0.50, min = 0.00, max = 2.53 mg/dl) were higher compared with controls (P<0.001). Finally, CRP was higher in non-cardiovertors vs. control group, p<0.001. After multivariate adjustment left atrial size (OR, 4.4) and CRP levels (OR, 3.3) were significantly associated with successful cardioversion to sinus rhythm.Conclusion — These results suggest that CRP has a strong association with PAF and support the hypothesis that CRP is a potent determinant of successful cardioversion of PAF in sinus rhythm.

Dispersion of atrial repolarization in patients with paroxysmal atrial fibrillation.

To study the role of the dispersion of atrial repolarization (DAR) in the genesis of atrial fibrillation (AF), monophasic action potentials (MAP) were recorded simultaneously from a catheter at the high lateral right atrium (HLRA) and a catheter moving around the high, middle and low lateral right atrium (RA) the high, anterior and posterior septal RA and the RA appendage in 15 patients with paroxysmal AF and 15 patients with atrioventricular nodal re-entry tachycardia (AVNRT) or concealed Wolff-Parkinson-White syndrome (WPW) without history of AF. After recordings during sinus rhythm (SR), MAPs were recorded during programmed stimulation (PS) via the HLRA catheter at a drive cycle length (CL) of 500 ms. Thus, MAPs were recorded simultaneously from 2 sites at a time and sequentially from 4 to 12 sites during SR, drive pacing and PS. Taking the MAP at the HLRA as reference, the dispersion of repolarization time (dispersion of RT) and its two components, the dispersions of activation time (dispersion of AT) and MAP duration (dispersion of MAP duration) among the 4 to 12 sites were calculated and taken as parameters of DAR. During SR and PS, the maximal dispersion of RT was significantly greater in AF than in control patients, 113+/-49 ms vs 50+/-28 ms (P<0.001) and 114+/-56 vs 70+/-43 ms (P<0.05) respectively. The increased dispersion of RT in the AF group was caused by increases in both dispersion of MAP duration and dispersion of AT. During SR and PS, DAR increased in patients with paroxysmal AF due to increases in dispersion of MAP duration and dispersion of AT, which suggests the involvement of both repolarization and conduction disturbances in the development of paroxysmal AF.