Clinical study to investigate the predictive parameters for the onset of atrial fibrillation in patients with essential hypertension

Persistent hypertension induces atrial remodeling and atrial fibrillation through DNA damage and ATM/CHK2/p53 signaling pathway

Atrial fibrillation (AF) is the most prevalent arrhythmia in clinical practice, with hypertension emerging as an independent risk factor. Previous literature has established associations between DNA damage response (DDR) and autophagy in relation to the pathogenesis of AF. The aim of this study was to evaluate the effect of atrial DNA damage response in persistent hypertension-induced atrial electrical and structural remodeling, and to further explore the potential therapeutic targets. Patient samples, spontaneous hypertensive rats (SHR) and angiotensin II (Ang II)-challenged HL-1 cells were employed to elucidate the detailed mechanisms. Bioinformatics analysis and investigation on human atrial samples revealed a critical role of DDR in the pathogenesis of AF. The markers of atrial DNA damage, DDR, autophagy, inflammation and fibrosis were detected by western blot, immunofluorescence, monodansyl cadaverine (MDC) assay and transmission electron microscopy. Compared with the control group, SHR exhibited significant atrial electrical and structural remodeling, abnormal increase of autophagy, inflammation, and fibrosis, which was accompanied by excessive activation of DDR mediated by the ATM/CHK2/p53 pathway. These detrimental changes were validated by in vitro experiments. Ang II-challenged HL-1 cells also exhibited significantly elevated γH2AX expression, and markers related to autophagy, inflammation as well as structural remodeling. Additionally, inhibition of ATM with KU55933 (a specific ATM inhibitor) significantly reversed these effects. Collectively, these data demonstrate that DNA damage and the subsequently overactivated ATM/CHK2/p53 pathway play critical roles in hypertension-induced atrial remodeling and the susceptibility to AF. Targeting ATM/CHK2/p53 signaling may serve as a potential therapeutic strategy against AF.

Hypertension and atrial fibrillation: the clinical impact of hypertension on perioperative outcomes of atrial fibrillation ablation and its optimal control for the prevention of recurrence

Hypertension (HTN) is one of the major risk factors for developing atrial fibrillation (AF), and it has been estimated that approximately 70% of hypertensive patients are at risk of developing AF. On the other hand, 60-80% of AF patients have HTN. These two diseases share many risk factors such as diabetes mellitus, obesity, alcohol consumption, and sleep apnea syndrome during their onset and disease progression. The mutual presence of these diseases has the potential to create a negative spiral, exacerbating each other's impact and ultimately leading to cardiovascular events such as heart failure and cerebrovascular disorders, thereby increasing mortality rates. With regard to the treatment of HTN, the variety of antihypertensive drugs and treatment options have significantly increased. Alongside the widespread adoption of antihypertensive therapy, a certain level of efficacy has been recognized in suppressing the incidence of new-onset AF. Catheter ablation is an established and effective treatment for AF. However, a notable recurrence rate persists. In recent years, management of these multiple risk factors has been recognized to be essential for suppressing AF recurrence, and recent guidelines for AF underscore the significance of proactively managing these risks before treatment. Notably, effective HTN management assumes paramount importance given its impact on the morbidity of AF patients. This review summarizes the correlation between HTN control before and after ablation and the risk of AF recurrence. The focus is on elucidating the pathophysiological background and its impact on clinical outcomes.

The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.

Electrocardiographic and Echocardiographic Predictors of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background

Patients with hypertrophic cardiomyopathy (HCM) have an increased prevalence of atrial fibrillation (AF) compared to the general population, and left atrium (LA) remodeling is strongly correlated with the risk of AF. This prospective, monocentric study aimed to assess the role of LA electrocardiographic and echocardiographic (structural and functional) parameters in predicting the risk for incident AF in patients with HCM.

Methods and Results

The study population consisted of 126 HCM patients in sinus rhythm (52.6 ± 16.2 years, 54 men), 118 of them without documented AF. During a median follow-up of 56 (7–124) months, 39 (30.9%) developed a new episode of AF. Multivariable analysis showed that LA booster pump function (assessed by ASr, HR = 4.24, CI = 1.84–9.75, and p = 0.038) and electrical dispersion (assessed by P wave dispersion – Pd, HR = 1.044, CI = 1.029–1.058, and p = 0.001), and not structural parameters (LA diameter, LA volume) were independent predictors of incident AF. Seventy-two patients had a LA diameter < 45 mm, and 16 of them (22.2%) had an AF episode during follow-up. In this subgroup, only Pd emerged as an independent predictor for incident AF (HR = 1.105, CI = 1.059–1.154, and p = 0.002), with good accuracy (AUC = 0.89).

Conclusion

Left atrium booster pump function (ASr) and electrical dispersion (Pd) are related to the risk of incident AF in HCM patients. These parameters can provide further stratification of the risk for AF in this setting, including in patients considered at lower risk for AF based on the conventional assessment of LA size.

Hypertension and Arrhythmias: A Clinical Overview of the Pathophysiology-Driven Management of Cardiac Arrhythmias in Hypertensive Patients

Because of demographic aging, the prevalence of arterial hypertension (HTN) and cardiac arrhythmias, namely atrial fibrillation (AF), is progressively increasing. Not only are these clinical entities strongly connected, but, acting with a synergistic effect, their association may cause a worse clinical outcome in patients already at risk of ischemic and/or haemorrhagic stroke and, consequently, disability and death. Despite the well-known association between HTN and AF, several pathogenetic mechanisms underlying the higher risk of AF in hypertensive patients are still incompletely known. Although several trials reported the overall clinical benefit of renin–angiotensin–aldosterone inhibitors in reducing incident AF in HTN, the role of this class of drugs is greatly reduced when AF diagnosis is already established, thus hinting at the urgent need for primary prevention measures to reduce AF occurrence in these patients. Through a thorough review of the available literature in the field, we investigated the basic mechanisms through which HTN is believed to promote AF, summarising the evidence supporting a pathophysiology-driven approach to prevent this arrhythmia in hypertensive patients, including those suffering from primary aldosteronism, a non-negligible and under-recognised cause of secondary HTN. Finally, in the hazy scenario of AF screening in hypertensive patients, we reviewed which patients should be screened, by which modality, and who should be offered oral anticoagulation for stroke prevention.

Association of clinic and ambulatory blood pressure with new-onset atrial fibrillation: A meta-analysis of observational studies

The aim of this study was to perform a meta‐analysis of studies evaluating the association of clinic and daytime, nighttime, and 24‐h blood pressure with the occurrence of new‐onset atrial fibrillation. We conducted a literature search through PubMed, Web of science, and Cochrane Library for articles evaluating the occurrence of new‐onset atrial fibrillation in relation to the above‐mentioned blood pressure parameters and reporting adjusted hazard ratio and 95% confidence interval. We identified five studies. The pooled population consisted of 7224 patients who experienced 444 cases of atrial fibrillation. The overall adjusted hazard ratio (95% confidence interval) was 1.05 (0.98‐1.13), 1.19 (1.11‐1.27), 1.18 (1.11‐1.26), and 1.23 (1.14‐1.32), per 10‐mmHg increment in clinic, daytime, nighttime, and 24‐h systolic blood pressure, respectively. The degree of heterogeneity of the hazard ratio estimates across the studies (Q and I‐squared statistics) were minimal. The results of this meta‐analysis strongly suggest that ambulatory systolic blood pressure prospectively predicts incident atrial fibrillation better than does clinic systolic blood pressure and that daytime, nighttime, and 24‐h systolic blood pressure are similarly associated with future atrial fibrillation.

New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation

Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.

Atrial remodeling and atrial fibrillation in acquired forms of cardiovascular disease

Atrial fibrillation (AF) is prevalent in common conditions and acquired forms of heart disease, including diabetes mellitus (DM), hypertension, cardiac hypertrophy, and heart failure. AF is also prevalent in aging. Although acquired heart disease is common in aging individuals, age is also an independent risk factor for AF. Importantly, not all individuals age at the same rate. Rather, individuals of the same chronological age can vary in health status from fit to frail. Frailty can be quantified using a frailty index, which can be used to assess heterogeneity in individuals of the same chronological age. AF is thought to occur in association with electrical remodeling due to changes in ion channel expression or function as well as structural remodeling due to fibrosis, myocyte hypertrophy, or adiposity. These forms of remodeling can lead to triggered activity and electrical re-entry, which are fundamental mechanisms of AF initiation and maintenance. Nevertheless, the underlying determinants of electrical and structural remodeling are distinct in different conditions and disease states. In this focused review, we consider the factors leading to atrial electrical and structural remodeling in human patients and animal models of acquired cardiovascular disease or associated risk factors. Our goal is to identify similarities and differences in the cellular and molecular bases for atrial electrical and structural remodeling in conditions including DM, hypertension, hypertrophy, heart failure, aging, and frailty.

Impact of the Duration and Degree of Hypertension and Body Weight on New-Onset Atrial Fibrillation

Hypertension and obesity are known risk factors for atrial fibrillation (AF). However, it is unclear whether uncontrolled, long-standing hypertension has a particularly profound effect on AF. Because they have a similar underlying pathophysiology, hypertension and obesity could act synergistically in the context of AF. We evaluated how various stages of hypertension and body weight status affect new-onset AF. We analyzed a total of 9 797 418 participants who underwent a national health checkup. Hypertension was classified into 5 stages: nonhypertension, prehypertension, hypertension without medication, hypertension with medication <5 years, and hypertension with medication ≥5 years. The participants were also stratified based on body mass index and waist circumference. During the 80 130 161 person×years follow-up, a total of 196 136 new-onset AF cases occurred. The incidence of new-onset AF gradually increased among the 5 stages of hypertension: the adjusted hazard ratio for each group was 1 (reference), 1.145, 1.390, 1.853, and 2.344 for each stage of hypertension. A graded escalation in the risk of new-onset AF was also observed in response to increased systolic and diastolic blood pressure. The incidence of new-onset AF correlated with body mass index and waist circumference, with obese people having a higher risk than others. Hypertension and obesity acted synergistically: obese people with hypertension on medication ≥5 years had the highest risk of AF. In conclusion, the degree and duration of hypertension, as well as the presence of hypertension, were important factors for new-onset AF. Body weight status was significantly associated with new-onset AF and acted synergistically with hypertension.

P-wave and QT dispersion in hypertensive disorders of pregnancy

Aim: To compare P-wave and QT dispersion values in hypertensive disorders of pregnancy and controls and also in preeclampsia, chronic hypertension, and gestational hypertension separately.Material and methods: We included 140 hypertensive pregnants and 110 healthy age-matched pregnants in this study. The hypertensive pregnants were divided into three subgroups: preeclampsia (n = 43), chronic hypertension (n = 51), and gestational hypertension (n = 46). P-wave and QT dispersion values were compared between groups.Results: Hypertensive pregnants had higher P-wave (41.74 ± 5.51 vs. 37.73 ± 5.62, p < .001) and QTc dispersion (45.44 ± 7.62 vs. 39.77 ± 8.34, p < .001) values. In subgroup analysis, P-wave dispersion and QTc dispersion were different between preeclamptic, chronic hypertensive, and gestational hypertensive patients. Also, they were significantly higher in chronic hypertension as compared to gestational hypertension and they were higher in preeclampsia than in gestational hypertension. No difference was found according to these parameters between preeclampsia and chronic hypertension. In correlation analysis, both P-wave dispersion and QTc dispersion were positively correlated with systolic (r = 0.409, p < .001 and r = 0.306, p < .001) and diastolic blood pressure (r = 0.390, p < .001 and r = 0.287, p < .001) which are main clinical determinants of hypertensive disorders.Conclusion: In clinical practice, chronic hypertensive pregnants are generally followed up in their future life for cardiovascular disorders. Also, we recommend that we must inform and follow preeclamptic patients for future cardiovascular diseases.

Atrial time and voltage dispersion are both needed to predict new-onset atrial fibrillation in ischemic stroke patients

BACKGROUND

Atrial fibrillation (AF) is a known risk factor for ischemic stroke. Electrocardiographic predictors of AF in population studies such as the Framingham Heart Study, as well as in hypertensive patients have demonstrated a predictive value of the P-wave duration for development of AF. QRS vector magnitude has had a predictive value in ventricular arrhythmia development. We aimed to assess the value of the three-dimensional P-wave vector magnitude and its relationship to P-wave duration for prediction of new-onset AF after ischemic stroke.

METHODS

First-ever ischemic stroke patients without AF at inclusion in the Lund Stroke Register were included. Measurements of P wave duration (Pd), QRS duration, corrected QT interval, and PQ interval were performed automatically using the University of Glasgow 12-lead ECG analysis algorithm. The P-wave vector magnitude (Pvm) was calculated automatically as the square root of the sum of the squared P-wave magnitudes in leads V6, II and one half of the P-wave amplitude in V2 ([Formula: see text]), based on the P-wave magnitude (Pvm) as defined by the visually transformed Kors' Quasi-orthogonal method.

RESULTS

The median age was 73 (IQR 63-80) years at stroke onset (135 males, 92 females). Multivariate predictors of new-onset atrial fibrillation included age > 65 years, hypertension, and Pd/Pvm. A cut-off value of 870 ms/mV gave sensitivity, specificity, positive and negative predictive values of 51, 79, 30 and 87%, respectively. The Pd/Pvm was the only ECG predictor of AF with a significant multivariate hazard ratio of 2.02 (95% CI 1.18 to 3.46, p = 0.010).

CONCLUSION

P-wave dispersion as measured by the Pd/Pvm was the only ECG parameter measured which independently predicted subsequent AF identification in a cohort of stroke patients. Further prospective studies in larger cohorts are needed to validate its clinical usefulness.

Ambulatory Blood Pressure Characteristics and Long-Term Risk for Atrial Fibrillation

BACKGROUND

We hypothesized that elevated nighttime systolic ambulatory blood pressure (ABP) yields additional information compared with daytime systolic ABP for the long-term risk of atrial fibrillation (AF) and perhaps should be taken into account in treatment strategies for preventing the increasing burden of AF during aging.

METHODS

A total of 903 subjects with or without hypertension aged 40 to 59 years, who were recruited to the Oulu Project Elucidating Risk of Atherosclerosis (OPERA) study, underwent ABP monitoring, thorough clinical examinations and laboratory tests.

RESULTS

After an average of 16.4 ± 3.6 years of follow-up, 91 (10%) of the study subjects had experienced a new-onset AF requiring a hospital emergency room or hospital visit. Of the components of baseline ABP, the nighttime mean systolic blood pressure had the strongest univariable association with the occurrence of AF (120.8 ± 15.9 vs. 116.4 ± 14.1 mm Hg, P = 0.006, in subjects with vs. without the occurrence AF). When the univariable predictors of AF, such as age, sex, body mass index, height, smoking history, alanine aminotransferase, uric acid, and fasting plasma glucose, were entered in the multivariable Cox hazards model, age (P < 0.001), and body mass index (P = 0.014) retained their significant predictive power. After adjustments in this clinical hazards model, the nighttime mean systolic blood pressure still predicted the occurrence of AF (hazards ratio = 1.07 per every 5 mm Hg increase, 95% confidence intervals = 1.004-1.15, P = 0.038).

CONCLUSION

Of the baseline ABP characteristics, the nighttime systolic blood pressure is a significant independent contributor to the long-term risk of new-onset AF requiring a hospital visit.

Relation of Functional Status to Risk of Development of Atrial Fibrillation

Identifying patients at risk is now important as there are demonstrable ways to alter disease progression which could potentially prevent atrial fibrillation (AF) and its complications. We sought whether impaired functional capacity was associated with risk of AF, independent of myocardial dysfunction. In this community-based study, asymptomatic participants aged ≥65 years were recruited if they had ≥1 risk factor (e.g., hypertension, diabetes mellitus, and obesity). Participants underwent baseline echocardiography (including measurement of myocardial mechanics) and six-minute walk test. The CHARGE-AF score was used to calculate 5-year risk of developing AF. Receiver operating characteristic curves were used to assess for independent risk factors for AF. A total of 607 patients (age 71 ± 5 years, men 47%) were studied at baseline and followed for at least 6 months. Patients in the higher AF risk groups were older and had increased rates of hypertension, diabetes mellitus, and ischemic heart disease (p <0.05). Greater AF risk was associated with lower exercise capacity, independent of lower mean global longitudinal strain, global circumferential strain, greater mean E/e' ratio, indexed left atrial volume and LV mass. Multivariate linear regression confirmed association of LV and functional capacity parameters with AF risk. Although functional capacity is impaired in AF, this association precedes the onset of AF. In conclusion, poor functional status is associated with AF risk, independent of LV function.

Electrocardiographic and Echocardiographic predictors of paroxysmal atrial fibrillation detected after ischemic stroke

BACKGROUND

Detection of atrial fibrillation after ischemic stroke is challenging due to its paroxysmal nature. We aimed to assess predictors of paroxysmal atrial fibrillation using non-invasive surface ECG and transthoracic echocardiography to select candidates for atrial fibrillation screening.

METHODS

Ischemic stroke patients without documented atrial fibrillation (n = 110, 67 ± 10 years, 40 female) and a control group of age- and gender-matched patients with history of paroxysmal atrial fibrillation prior to stroke (n = 55, 67 ± 10 years, 19 female) comprised the study sample. Using non-invasive ECG monitoring for three weeks, short episodes of paroxysmal atrial fibrillation were detected in 24 of 110 patients (22 %). The standard 12-lead ECG with sinus rhythm at stroke onset was digitally processed and analyzed. Transthoracic echocardiography data were reviewed for these patients.

RESULTS

Atrial fibrillation history was independently associated with P terminal force in lead V 1 > 40 mm*ms (OR 4.04 95 % CI 1.34-12.14, p = 0.013) and left atrial volume index (OR 1.08 95 % CI 1.03-1.13, p = 0.002; for LAVI > 40 mL/m² OR 6.40 95 % CL 1.47-27.91, p = 0.013). Among patients without atrial fibrillation history, no ECG characteristics were predictive of atrial fibrillation detected after stroke. Left atrial volume index remained an independent predictor of atrial fibrillation detected after stroke (OR 1.09 95 % CI 1.02-1.16, p = 0.017). A cutoff of <40 mL/m² had an 84 % negative predictive value for ruling out atrial fibrillation on ambulatory monitoring with a sensitivity of 50 % and a specificity of 86 %.

CONCLUSION

In a post hoc analysis, left atrial dilatation assessed by left atrial volume index independently predicted atrial fibrillation after stroke in patients without prior atrial fibrillation history, while the other clinical or ECG markers were not predictive of atrial fibrillation detected early after ischemic stroke.

TRIAL REGISTRATION

This study is a post hoc analysis from the prospective case-control study registered in December 2011, ClinicalTrials.gov ID: NCT01325545 .

Does pregnancy-induced hypertension affect the electrophysiology of the heart?

Pregnancy-induced hypertension (PIHT) increases both maternal and neonatal mortality and morbidity in pregnant women. We sought to investigate the electrocardiographic findings in pregnant women with PIHT. Seventeen pregnant women (29.4 ± 5 years) with PIHT and 24 pregnant women (27.3 ± 6.1 years) with normal blood pressure (control group) were included in the study. A 12-lead surface electrocardiogram was used to evaluate the electrocardiographic parameters. Pregnant women with PIHT had higher blood pressure (p = 0.001). The Tp-e interval was longer in PIHT pregnant women at 83.5 ± 7.8 ms versus 75.8 ± 8.4 ms in the control group (p = 0.007). The Tp-e/QTc ratio was higher in pregnant women with PIHT than that in healthy controls (0.19 ± 0.02 vs. 0.18 ± 0.02, respectively). This study demonstrated that Pd, QTd and the P wave durations were similar in the PIHT pregnant women and control group, but the Tp-e and Tp-e/QTc ratio were higher in pregnant women with PIHT than in normotensive pregnant women.

Predictors of new onset atrial fibrillation during 10-year follow-up after first-ever ischemic stroke

BACKGROUND

Paroxysmal atrial fibrillation (AF) may be underdiagnosed in ischemic stroke patients but may be pivotal for initiation of oral anticoagulation therapy. We assessed clinical and ECG predictors of new-onset AF during 10-year follow-up (FU) in ischemic stroke patients.

METHODS

The study sample comprised of 227 first-ever ischemic stroke patients without AF (median age 73, interquartile range 25%-75% 63-80years, 92 female) and 1:1 age- and gender-matched controls without stroke and AF enrolled in the Lund Stroke Register from March 2001 to February 2002. New-onset AF during FU was assessed by screening through regional ECG database and by record linkage with Swedish National Patient Register. The standard 12-lead sinus rhythm ECGs at stroke admission were retrieved from electronic database and digitally processed. Clinical baseline characteristics were studied using medical records.

RESULTS

During FU, AF was found in 39 stroke patients and 30 controls, p=0.296. In stroke patients in multivariate Cox regression analysis AF was associated with hypertension (HR 3.45 CI 95% 1.40-3.49, p=0.007) and QRS duration (HR 1.02 CI 95% 1.00-1.03, p=0.049). High cardiovascular risk was predictive for AF development: for CHADS2≥4 HR 2.46 CI 95% 1.45-4.18, p=0.001 and for CHA2DS2-VASc≥5 HR 2.29 CI 95% 1.43-3.68, p=0.001. New onset AF was not associated with baseline ischemic stroke: HR 1.46 95% CI 0.90-2.35, p=0.121.

CONCLUSION

High CHADS2 and CHA2DS2-VASc scores, but not baseline ischemic stroke, predict new onset AF in FU. QRS duration might be considered a potential risk marker for prediction of AF after ischemic stroke.

Longitudinal evaluation of P-wave dispersion and P-wave maximum in children after transcatheter device closure of secundum atrial septal defect

Transcatheter device closure of the secundum atrial septal defect (ASD) in children prevents atrial arrhythmias in older age. However, the benefits of favourable atrial electrocardiographic markers in these children remain elusive. We aimed to review the electrocardiographic markers of atrial activity in a longitudinal fashion. We retrospectively reviewed longitudinal data of all children who underwent transcatheter device closure at the National University Hospital between 2004 and 2013. The inclusion criteria included the presence of a secundum-type ASD with left to right shunt and evidence of increased right ventricular volume load (Q p/Q s ratio >1.5 and/or right ventricular dilatation). A total of 25 patients with a mean follow-up of 44.7 ± 33.47 (7.3-117.4) months were included. P maximum and P dispersion decreased at 2 months, P amplitude at 1 week and remained so until last follow-up. A positive trend was seen with a correlation coefficient of +0.12 for P maximum, +0.08 for P dispersion and 0.34 for P amplitude. There was a higher baseline P amplitude and P dispersion in patients who were older than 10 years and a non-significant trend to support an increase in both P maximum (71.0 ± 8.8 vs. 73.2 ± 12.7), P dispersion (17.0 ± 6.5 vs. 22.0 ± 11.3) and P amplitude (0.88 ± 0.25 vs. 1.02 ± 0.23) in patients with an ASD more than 15 mm compared with an ASD <15 mm. There is reduction in both P maximum and P dispersion as early as 2 months, which persisted on follow-up. Earlier closure may result in more favourable electrocardiographic results.

Blood Pressure and Atrial Fibrillation: A Combined AF-CHF and AFFIRM Analysis

BACKGROUND

Hypertension is an established risk factor for new-onset atrial fibrillation (AF). However, the relationship between blood pressure and recurrent AF is less well understood.

METHODS AND RESULTS

A pooled analysis of patient-level data from AFFIRM and AF-CHF trials was conducted on all 2,715 patients with paroxysmal or persistent AF, 68 ± 8 years, 66% male, randomized to rhythm control and followed for 40.6 ± 16.5 months. We assessed the impact of a baseline systolic blood pressure (SBP; <120 mmHg [N = 1,008], 120-140 mmHg [N = 930], >140 mmHg [N = 777]) on recurrent AF and proportion of time spent in AF. In patients with LVEF >40% (N = 1,719), SBP was not associated with recurrent AF in multivariate regression analyses (P = 0.752). In contrast, in patients with LVEF ≤40% (N = 996), the AF recurrence rate was higher in those with an SBP >140 mmHg compared to 120-140 mmHg (hazard ratio 1.47; 95% CI [1.12-1.93], P = 0.005). The rate of recurrent AF was similar in patients with SBP <120 mmHg compared to 120-140 mmHg (hazard ratio 1.15; 95% CI [0.92-1.43], P = 0.225). Consistently, the proportion of time spent in AF was not influenced by SBP in patients with LVEF >40% (P = 0.645). However, in patients with LVEF ≤40%, the adjusted mean proportion of time spent in AF was 17.2% if SBP was <120 mmHg, 15.4% for SBP 120-140 mmHg, and 24.0% for SBP >140 mmHg (P = 0.025).

CONCLUSION

Systolic blood pressure is an important determinant of recurrent AF and overall AF burden in patients with left ventricular dysfunction (LVEF≤40%) but not in those with preserved ventricular function.

Incident atrial fibrillation hazard in hypertensive population: a risk function from and for clinical practice

Determining the risk of atrial fibrillation within the hypertensive population without ischemic vascular disease would aid in decision making on preventive approaches. Accordingly, we aimed to estimate the risk of incident atrial fibrillation in this population. We conducted an historical cohort study between July 1, 2006, and December 31, 2011, using anonymized longitudinal patient information from primary care and hospital discharge records contained in the System for the Development of Research in Primary Care database. We included 255 440 hypertensive patients, aged ≥55 years at the time of study entry. Individuals with previous atrial fibrillation, ischemic heart disease, stroke, and peripheral artery disease were excluded. To build the incident atrial fibrillation risk function, a derivation and a validation cohort were defined, representing 60% and 40% of the entire database, respectively, and a Cox proportional hazards model was fitted. Atrial fibrillation incidence was 7.24 per 1000 person-years (95% confidence interval, 7.08-7.40). The final model included age, weight, total cholesterol, heart failure, valvular heart disease, and antihypertensive treatment. Its concordance index (standard error) was 0.769 (0.004) and 0.768 (0.005) in the derivation and validation datasets, respectively. This research provides a tool, built with variables from daily clinical practice, that can be readily used in the primary care setting to predict atrial fibrillation incidence in the hypertensive population without ischemic vascular disease. The tool may help tailor individualized diagnostic and preventive care decisions.

Blockade of brain angiotensin II type 1 receptor inhibits the development of atrial fibrillation in hypertensive rats

BACKGROUND

Hypertension is a powerful risk factor of atrial fibrillation (AF). The pathophysiology of AF with hypertension is associated with sympathoexcitation or the renin-angiotensin system; however, current therapies cannot sufficiently prevent its development. We previously revealed that brain angiotensin II type 1 receptor (AT1R) blockade causes a depressor response via sympathoinhibition. Herein, we evaluated whether brain AT1R contributes to AF development in hypertensive rats.

METHODS

We divided the stroke-prone spontaneously hypertensive rats (SHRSP) treated with intracerebroventricular (ICV) infusion of vehicle, ICV infusion of losartan (S-LOS), or oral administration of hydralazine (S-HYD); and Wistar Kyoto rats treated with ICV S-VEH.

RESULTS

Two weeks later, systolic blood pressure was significantly lower in the S-LOS group than in the S-VEH group and was even lower in the S-HYD group. Urinary norepinephrine excretion for 24h, an indirect marker of sympathoexcitation, significantly reduced in the S-LOS group but increased in the S-HYD group despite depressor response. AF was induced by transesophageal burst pacing. AF duration was significantly shorter in the S-LOS group than in the S-VEH group (5.0±0.4 vs. 15.2±3.7 s; n = 8 each; P < 0.05). However, it was significantly longer in the S-HYD group than in the S-VEH group. Interstitial atrial fibrosis and echocardiographic parameters did not differ between the SHRSP groups.

CONCLUSIONS

Brain AT1R blockade suppresses AF inducibility and maintenance independent of depressor response in hypertensive rats.

P-wave duration changes and dispersion in preeclampsia

OBJECTIVE

The purpose of this research was to study P wave parameters to determine the association between preeclampsia and future cardiovascular risk and to study the possible correlation between P waves and severity of preeclampsia.

STUDY DESIGN

In this case-control study 58 pregnant women with preeclampsia and 30 normal pregnant women were compared by measuring maximum and minimum P-wave durations and P-wave dispersion (Pd) in the late third trimester.

RESULTS

Minimum P wave values were lower and Pd values were higher, both significantly, in the preeclampsia groups than in the control group. In addition, the Pd values of the severe preeclampsia group were higher compared to that of the mild preeclampsia group.

CONCLUSION

Preeclampsia predisposes the patient to future cardiovascular complications including atrial or ventricular arrhythmias, but validated tools to assess the risks are yet not available. P-wave duration and Pd constitute a recent contribution to the field of noninvasive electrocardiology. Our data clearly demonstrated that minimum P wave and Pd values were significantly altered in preeclamptic pregnant women when compared to the controls. This important association can be used to screen women for increased risk in order to better target counseling regardinglifestyle modifications and to follow up and manage women with a history of preeclampsia more closely.

[P wave dispersion increased in childhood depending on blood pressure, weight, height, and cardiac structure and function]

INTRODUCTION

Increased P wave dispersion are identified as a predictor of atrial fibrillation. There are associations between hypertension, P wave dispersion, constitutional and echocardiographic variables. These relationships have been scarcely studied in pediatrics.

OBJECTIVE

The aim of this study was to determine the relationship between P wave dispersion, blood pressure, echocardiographic and constitutional variables, and determine the most influential variables on P wave dispersion increases in pediatrics.

METHOD

In the frame of the PROCDEC II project, children from 8 to 11 years old, without known heart conditions were studied. Arterial blood pressure was measured in all the children; a 12-lead surface electrocardiogram and an echocardiogram were done as well.

RESULTS

Left ventricular mass index mean values for normotensive (25.91±5.96g/m(2.7)) and hypertensive (30.34±8.48g/m(2.7)) showed significant differences P=.000. When we add prehypertensive and hypertensive there are 50.38% with normal left ventricular mass index and P wave dispersion was increased versus 13.36% of normotensive. Multiple regression demonstrated that the mean blood pressure, duration of A wave of mitral inflow, weight and height have a value of r=0.88 as related to P wave dispersion.

CONCLUSIONS

P wave dispersion is increased in pre- and hypertensive children compared to normotensive. There are pre- and hypertensive patients with normal left ventricular mass index and increased P wave dispersion. Mean arterial pressure, duration of the A wave of mitral inflow, weight and height are the variables with the highest influence on increased P wave dispersion.

Left atrial appendage function in prediction of paroxysmal atrial fibrilation in patients with untreated hypertension

Abstract The onset of AF results in a significant increase in mortality rates and morbidity in hypertensive patients and this rhythm disorder exposes patients to a significantly increased risk of cerebral or peripheral embolisms. Tissue Doppler imaging was found to be useful in early detection of myocardial dysfunction in several diseases. It was shown that tissue Doppler analysis of the walls of the left atrial appendage (LAA) can give accurate information about the function of the LAA in hypertensive patients. In this study, we aimed to investigate and identify the specific predictive parameters for the onset of AF in patients with hypertension with tissue Doppler imaging of LAA. We studied age and sex matched 57 untreated hypertensive patients with paroxysmal atrial fibrillation (PAF) and 27 untreated hypertensive subjects without PAF. With transthoracic echocardiography, diastolic mitral A-velocity and LA maximal volume index which reflects reservoir function of left atrium was measured, with transesophageal echocardiography, LAA emptying velocity (LAA-PW D2) and tissue Doppler contracting velocity of LAA (LAA-TDI-D2) were measured. LA maximal volume index of the groups (22.28 ± 3.59 mL/m(2) in Group 1 versus 20.37 ± 3.97 mL/m(2) in Group 2, p = 0.07) and diastolic mitral A-velocity [0.93 (0.59-1.84) m/s in patients with PAF versus 0.90 (0.62-1.76) m/s in patients without PAF, p = 0.26] was not significantly different between study groups, during TEE, LAA-PW D2 (0.31 ± 0.04 m/s in Group 1 versus 0.33 ± 0.03 m/s in Group 2, p = 0.034) and LAA-TDI-D2 (0.18 ± 0.04 m/s in Group 1 versus 0.21 ± 0.05 m/s in Group 2, p = 0.014) were significantly decreased in Group 1. In this study, we found that in hypertensive PAF patients despite normal global LA functions, LAA contracting function was deteriorated. Tissue Doppler analysis of LAA is clinically usefull approach to detect the risk of developing PAF in hypertensives.

Serum potassium levels and the risk of atrial fibrillation: the Rotterdam Study

BACKGROUND

Atrial fibrillation is the most common sustained arrhythmia in the elderly. Serum potassium is associated with ventricular arrhythmias and cardiac arrest. Little is known about the association of serum potassium with atrial fibrillation. The objective of this study was to investigate the association of serum potassium and the risk of atrial fibrillation in a population based setting.

METHODS

The study was performed within the prospective population-based Rotterdam Study. The study population consisted of 4059 participants without atrial fibrillation at baseline for whom baseline levels of serum potassium were measured. Atrial fibrillation was ascertained from centre visit ECG assessments as well as medical records.

RESULTS

During a mean follow up of 11.8 years (SD=5.2 yr), 474 participants developed atrial fibrillation. Participants with hypokalemia (<3.5 mmol/l) had a higher risk of atrial fibrillation (HR: 1.63, 95%CI: 1.03-2.56) than those with normokalemia (3.5-5.0 mmol/l). This association was independent of age, sex, serum magnesium, and other potential confounders. Especially in participants with a history of myocardial infarction, those with hypokalemia had a higher risk of atrial fibrillation than those with normokalemia (HR: 3.81, 95%-CI: 1.51-9.61).

CONCLUSIONS

In this study low serum levels of potassium were associated with a higher risk of atrial fibrillation.

During ablation for atrial fibrillation, is simultaneous renal artery ablation appropriate?

Over the past few decades, the mainstay of hypertension management has been pharmacological therapy; however, there is now a growing body of evidence that drug-resistant hypertension can be managed effectively by renal artery ablation. Several studies have documented the feasibility and safety of this treatment, although data regarding long-term outcomes are still emerging. Atrial fibrillation (AF) and hypertension commonly coexist, and recent work has demonstrated improved outcomes from catheter ablation of AF with concomitant renal artery denervation at little extra cost in terms of time and resource. The aim of this review is to explore the link between hypertension and AF, the synergistic effect of renal artery ablation on AF ablation, explain how this may work and address unanswered questions.

The effect of levobupivacaine and bupivacaine on QT, corrected QT (Qtc), and P wave dispersions in cesarean section

BACKGROUND AND OBJECTIVES

In our study we aimed to investigate the effect of bupivacaine and levobupivacaine on QT, corrected QT (QTc), and P wave dispersion durations during spinal anesthesia in cesarean section.

METHODS

Sixty parturients scheduled for elective cesarean section in ASA I-II risk groups were included in the study. Baseline electrocardiographic (ECG) records of the patients were obtained in the operation room. Heart rate (HR), non-invasive blood pressure (NIBP), peripheral oxygen saturation (SpO2) and respiration rates (RR) were recorded. Venous cannulation was performed with 18G cannula and fluid preload made with 10 mL.kg(-1). Lactated Ringer solution. After fluid preload, second ECG recordings were taken and the patients were randomly separated into two groups. Group B (n = 30) received 10mg of bupivacaine and Group L (n = 30) received 10mg of levobupivacaine for spinal anesthesia. ECG recordings were repeated at 1, 5 and 10 minutes after spinal block. HR, NIBP, SpO2, RR and sensory block levels were also recorded at the same time intervals. At predetermined time intervals of spinal anesthesia, P wave dispersion (Pwd), QT dispersion (QTd), and QTc dispersion (QTcd) durations were measured from ECG records. QT and QTc durations are calculated with Bazzett formula.

RESULTS

There was no difference between two groups according to block levels, hemodynamic parameters, Pwd, QTd, QTc and QTcd durations.

CONCLUSION

Bupivacaine and levobupivacaine may be preferred in spinal anesthesia in pregnant patients who have extended Pwd and QTcd preoperatively.

Ambulatory blood pressure monitoring in elderly patients with chronic atrial fibrillation: is it absolutely contraindicated or a useful tool in clinical practice and research?

The aim of this study was to test whether ambulatory blood pressure monitoring (ABPM) in elderly patients with atrial fibrillation (AF) is as feasible and reliable as ABPM is in patients with normal sinus rhythm (SR). Studies of ABPM in the elderly remain limited, and the use of this method in patients with AF remains controversial. The Italian SIIA 2008 guidelines consider ABPM 'absolutely contraindicated' for AF patients. This study was conducted on 200 hospitalized patients aged ≥ 65 years (68% females; mean age 82.4 ± 6.3 years): 100 patients with SR and 100 patients with permanent AF. Each patient completed serial blood pressure (BP) measurements with a clinical sphygmomanometer (Sphyg) and ABPM. Differences in mean heart rate (HR) between patient groups were not statistically significant. A total of 99.5% of patients were hypertensive. There were no significant differences between SR and AF patients in mean systolic BP (SBP) and diastolic BP (DBP) values, as measured with the Sphyg or by ABPM. Compared with the Sphyg, errors associated with BP measurements obtained by ABPM did not significantly differ between the two groups. ABPM proved to be as feasible as Sphyg measurements in both AF patients (intraclass correlation coefficients=0.73, 0.67 and 0.74 for SBP, DBP and HR, respectively) and SR patients (intraclass correlation coefficients=0.74, 0.58 and 0.67 for SBP, DBP and HR, respectively). A Bland-Altman plot analysis confirmed that there was good agreement between the two methods. Stable AF (HR 60-100 b.p.m.) should not be considered as an absolute contraindication for the use of ABPM, even in the elderly; it could be a 'relative' contraindication for very unstable AF patients.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Hypertension and atrial fibrillation: diagnostic approach, prevention and treatment. Position paper of the Working Group 'Hypertension Arrhythmias and Thrombosis' of the European Society of Hypertension

Hypertension is the most common cardiovascular disorder and atrial fibrillation is the most common clinically significant arrhythmia. Both these conditions frequently coexist and their prevalence increases rapidly with aging. There are different risk factors and clinical conditions predisposing to the development of atrial fibrillation, but due its high prevalence, hypertension is still the main risk factor for the development of atrial fibrillation. Several pathophysiologic mechanisms (such as structural changes, neurohormonal activation, fibrosis, atherosclerosis, etc.) have been advocated to explain the onset of atrial fibrillation. The presence of atrial fibrillation per se increases the risk of stroke but its coexistence with high blood pressure leads to an abrupt increase of cardiovascular complications. Different risk models are available for the risk stratification and the prevention of thromboembolism in patients with atrial fibrillation. In all of them hypertension is present and is an important risk factor. Antihypertensive treatment may contribute to reduce this risk, and it seems some classes are superior to others in the prevention of new-onset atrial fibrillation and prevention of stroke. Antithrombotic treatment with warfarin is effective in the prevention of thromboembolic events, although quite recently, new classes of anticoagulants that do not require international normalized ratio monitoring have been introduced with promising results.

Atrial fibrillation and heart failure parallels: lessons for atrial fibrillation prevention

Heart failure (HF) and atrial fibrillation (AF) are 2 of the most common cardiovascular diseases encountered in clinical practice, and the prevalence of these diseases continues to grow worldwide with the aging of the global population. While recognizing that AF is a heterogeneous disorder, we submit that the parallels between AF and HF may arise because many cases of AF and HF result from the cumulative exposure of the atria and ventricles to a common set of systemic cardiovascular risk factors. Over time, exposure to risk factors promotes development of atrial and ventricular structural and functional abnormalities through activation of several biologic pathways in concert: upregulation of neurohormonal signaling cascades, release of inflammatory mediators, programmed cell death, and fibrosis. Cardiac structural remodeling occurs in concert with electrophysiologic remodeling, both of which contribute to atrial and ventricular rhythm disturbances, including AF. AF and HF, instead of representing distinct disease processes, often represent different endpoints along a disease continuum. By reviewing some of the mechanistic parallels between AF and HF, we hope to emphasize the connection between established cardiovascular risk factors, cardiac remodeling and AF, with a view to promote strategies for AF prevention.

Electrocardiographic findings in patients with primary dysmenorrhea

INTRODUCTION

Primary dysmenorrhea (PD), which is characterized by painful menstrual cycles, is one of the common clinical problems in young adult women. The aim of this study was to investigate the risk of cardiac arrhythmias in PD patients by using the electrocardiographic (ECG) parameters.

METHODS

Forty patients diagnosed with PD and 30 age-matched normal controls were included in this study. ECGs were performed by using 12-leads with 10 mV amplitude and 25 mm/sec velocity. P and QT waves were manually marked along the isoelectric line. P maximum, P minimum, QT maximum and QT minimum were measured on the surface 12-leads ECG, and the P wave and QT dispersions were calculated.

RESULTS

There was not any significant correlation of P wave dispersion and QT dispersion between the age, sex, body mass index, hemoglobin, fasting blood glucose or any other laboratory parameters. P wave dispersion was significantly longer in the PD group than the control group (61.4 ± 19 msec versus 57 ± 14 msec, P = 0.01). The P minimum duration was significantly shorter in the PD group compared with the control group (36 ± 16 msec versus 41 ± 9 msec, P = 0.03). QT dispersion was significantly higher in the PD group compared with normal controls (76 ± 23 msec versus 58 ± 16 msec, P = 0.02).

CONCLUSION

These results show that PD can be associated with cardiac arrhythmias, especially atrial fibrillation, by increasing P wave dispersion and ventricular arrhythmia risk because of an increased QT interval.

Comparison of P-wave dispersion in healthy dogs, dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction

BACKGROUND

P-wave dispersion (Pd) is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs.

METHODS

The current study was aimed at determining proper value of Pd in healthy dogs (group I), dogs with chronic valvular disease (group II) and dogs with disturbances of supraventricular conduction (group III). The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4) from 5 cardiac cycles.

RESULTS

The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p<0.01) in dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction. In dogs with the atrial enlargement the P-wave dispersion is also higher than in healthy dogs, although no significant correlation between the size of left atria and Pd was noticed (p=0.1, r=0,17).

CONCLUSIONS

The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.