Latent Arterial Hypertension in Apparently Lone Atrial Fibrillation

Concealed Coronary Atherosclerosis In Idiopathic Paroxysmal Atrial Fibrillation is Associated with Imminent Cardiovascular Diseases

Background

Previous research showed a significant difference in the presence of subclinical coronary artery disease (CAD) on cardiac CT angiography (CTA) between patients with idiopathic paroxysmal atrial fibrillation (iAF) versus a matched sinus rhythm population (iSR). Here we present 5-year follow-up data and the consequences of subclinical CAD on baseline CTA on the development of cardiovascular disease in iAF.

Methods

In 99 iAF patients (who underwent CTA as part of work-up for pulmonary vein isolation) and 221 matched iSR controls (who underwent CTA for CAD assessment), the incidence of hypertension, diabetes and major cardiovascular events (MACCE) during follow-up was obtained. Multivariable Cox regression analysis was used to reveal predictors of incident cardiovascular disease in the iAF group.

Results

During a follow-up of 68±11 months, over one third of patients developed cardiovascular disease, with no difference between iAF and iSR (log-rank p=0.56), and comparable low rates of MACCE (4.0% vs 5.0%,p=0.71). Within the iAF group, age (HR1.12(1.03-1.20);p=0.006), left atrial diameter (HR1.16(1.03-1.31);p=0.01), Segment Involvement Score (total number of coronary segments with atherosclerotic plaque; HR1.43(1.09-1.89);p=0.01) and the number of calcified plaques on CTA (HR0.53(0.30-0.92);p=0.01) were independent predictors of incident cardiovascular disease.

Conclusions

Subclinical coronary disease on CTA may be useful to identify the subset of patients with iAF that harbour concealed cardiovascular risk factors and need intensive clinical follow-up to ensure timely initiation of appropriate therapy once CV disease develops, including anticoagulation and vascular prophylactic therapy.

Characteristics and outcomes of atrial fibrillation in patients without traditional risk factors: an RE-LY AF registry analysis

AIMS

Data on patient characteristics, prevalence, and outcomes of atrial fibrillation (AF) patients without traditional risk factors, often labelled 'lone AF', are sparse.

METHODS AND RESULTS

The RE-LY AF registry included 15 400 individuals who presented to emergency departments with AF in 47 countries. This analysis focused on patients without traditional risk factors, including age ≥60 years, hypertension, coronary artery disease, heart failure, left ventricular hypertrophy, congenital heart disease, pulmonary disease, valve heart disease, hyperthyroidism, and prior cardiac surgery. Patients without traditional risk factors were compared with age- and region-matched controls with traditional risk factors (1:3 fashion). In 796 (5%) patients, no traditional risk factors were present. However, 98% (779/796) had less-established or borderline risk factors, including borderline hypertension (130-140/80-90 mmHg; 47%), chronic kidney disease (eGFR < 60 mL/min; 57%), obesity (body mass index > 30; 19%), diabetes (5%), excessive alcohol intake (>14 units/week; 4%), and smoking (25%). Compared with patients with traditional risk factors (n = 2388), patients without traditional risk factors were more often men (74% vs. 59%, P < 0.001) had paroxysmal AF (55% vs. 37%, P < 0.001) and less AF persistence after 1 year (21% vs. 49%, P < 0.001). Furthermore, 1-year stroke occurrence rate (0.6% vs. 2.0%, P = 0.013) and heart failure hospitalizations (0.9% vs. 12.5%, P < 0.001) were lower. However, risk of AF-related re-hospitalization was similar (18% vs. 21%, P = 0.09).

CONCLUSION

Almost all patients without traditionally defined AF risk factors have less-established or borderline risk factors. These patients have a favourable 1-year prognosis, but risk of AF-related re-hospitalization remains high. Greater emphasis should be placed on recognition and management of less-established or borderline risk factors.

Idiopathic atrial fibrillation patients rapidly outgrow their low thromboembolic risk: a 10-year follow-up study

Background

Healthy atrial fibrillation (AF) patients will eventually outgrow their low thromboembolic risk. The purpose of this study is to compare the development of cardiovascular disease in healthy AF patients as compared to healthy sinus rhythm patients and to assess appropriate anticoagulation treatment.

Methods

Forty-one idiopathic paroxysmal AF patients (56 ± 10 years, 66% male) were compared with 45 healthy sinus rhythm patients. Patients were free of hypertension, antihypertensive and antiarrhythmic drugs, diabetes, congestive heart failure, coronary artery or peripheral vascular disease, previous stroke, thyroid, pulmonary and renal disease, and structural abnormalities on echocardiography.

Results

Baseline characteristics and echocardiographic parameters were the same in both groups. During 10.7 ± 1.6 years, cardiovascular disease and all-cause death developed significantly more often in AF patients as compared to controls (63% vs 31%, log rank p < 0.001). Even after the initial 5 years of follow-up, survival curves show divergent patterns (log rank p = 0.006). Mean duration to reach a CHA₂DS₂-VASc score > 1 among AF patients was 5.1 ± 3.0 years. Five of 24 (21%) patients with CHA₂DS₂-VASc > 1 did not receive oral anticoagulation therapy at follow-up. Mean duration of over- or undertreatment with oral anticoagulation in patients with CHA₂DS₂-VASc > 1 was 5 ± 3.0 years.

Conclusion

The majority of recently diagnosed healthy AF patients develop cardiovascular diseases with a consequent change in thromboembolic risk profile within a short time frame. A comprehensive follow-up of this patient category is necessary to avoid over- and undertreatment with anticoagulants.

A novel management program for hypertension

In this article, we describe a comprehensive management program for hypertension (HTN), based on the experience of leading cardiovascular centers in China. This comprehensive approach, adhering to a number of core principles, includes diagnosis and therapeutic interventions. Therapeutic management includes lifestyle changes, risk factor management and pharmacological intervention and should allow reliable lowering blood pressure (BP). Additional paragraphs discuss the relationship between paroxysmal atrial fibrillation (PAF), and HTN.

Emerging risk factors and the dose-response relationship between physical activity and lone atrial fibrillation: a prospective case-control study

Aims

The role of high-intensity exercise and other emerging risk factors in lone atrial fibrillation (Ln-AF) epidemiology is still under debate. The aim of this study was to analyse the contribution of each of the emerging risk factors and the impact of physical activity dose in patients with Ln-AF.

Methods and results

Patients with Ln-AF and age- and sex-matched healthy controls were included in a 2:1 prospective case–control study. We obtained clinical and anthropometric data transthoracic echocardiography, lifetime physical activity questionnaire, 24-h ambulatory blood pressure monitoring, Berlin questionnaire score, and, in patients at high risk for obstructive sleep apnoea (OSA) syndrome, a polysomnography. A total of 115 cases and 57 controls were enrolled. Conditional logistic regression analysis associated height [odds ratio (OR) 1.06 [1.01–1.11]], waist circumference (OR 1.06 [1.02–1.11]), OSA (OR 5.04 [1.44–17.45]), and 2000 or more hours of cumulative high-intensity endurance training to a higher AF risk. Our data indicated a U-shaped association between the extent of high-intensity training and AF risk. The risk of AF increased with an accumulated lifetime endurance sport activity ≥2000 h compared with sedentary individuals (OR 3.88 [1.55–9.73]). Nevertheless, a history of <2000 h of high-intensity training protected against AF when compared with sedentary individuals (OR 0.38 [0.12–0.98]).

Conclusion

A history of ≥2000 h of vigorous endurance training, tall stature, abdominal obesity, and OSA are frequently encountered as risk factors in patients with Ln-AF. Fewer than 2000 total hours of high-intensity endurance training associates with reduced Ln-AF risk.

Relation of Biomarkers of Inflammation and Oxidative Stress with Hypertension Occurrence in Lone Atrial Fibrillation

We compared plasma levels of biomarkers of inflammation (CRP) and oxidation (oxLDL), determined at study inclusion in lone atrial fibrillation (LAF) patients (48.6 ± 11.5 years; 74.0% men) and sinus rhythm controls (49.7 ± 9.3 years; 72.7% men, P > 0.05), and investigated the association of baseline CRP and oxLDL levels with the risk for vascular disease (VD) development (hypertension, cerebrovascular disease, coronary/peripheral artery disease, and pulmonary embolism) during prospective follow-up. Baseline CRP (1.2 [0.7–1.9] mg/L versus 1.1 [0.7–1.6] mg/L) and oxLDL levels (66.3 ± 21.2 U/L versus 57.1 ± 14.6 U/L) were higher in LAF patients (both P < 0.05). Following a median of 36 months, incident VD occurred in 14 (28.0%) LAF patients, all of whom developed arterial hypertension, and in 5 (11.4%) controls (hypertension, n = 4; coronary artery disease, n = 1), P < 0.05. LAF patients developed VD more frequently and at a younger age. Both CRP (HR, 2.54; 95% CI, 1.26–5.12; P = 0.009) and oxLDL (HR, 2.24; 95% CI, 1.14–4.40; P = 0.019) were multivariate predictors of incident hypertension in LAF patients, but not in the controls. Further research should clarify clinical relevance of investigated biomarkers for risk stratification and treatment of LAF patients.

The Role Of Renin Angiotensin System In Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent arrhythmia and its incidence is on the rise. AF causes significant morbidity and mortality leading to rising AF-related health care costs. There is experimental and clinical evidence from animal and human studies that suggests a role for the renin angiotensin system (RAS) in the etiopathogenesis of AF. This review appraises the current understanding of RAS antagonism, using angiotensin converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB) and aldosterone antagonists (AA), for prevention of AF. RAS antagonism has proven to be effective for primary and secondary prevention of AF in subjects with heart failure and left ventricular (LV) dysfunction.However, most of the evidence for the protective effect of RAS antagonism is from clinical trials that had AF as a secondary outcome or from unspecified post-hoc analyses. The evidence for prevention in subjects without heart failure and with normal LV function is not as clear. RAS antagonism, in the absence of concomitant antiarrhythmic therapy, was not shown to reduce post cardioversion AF recurrences. RAS antagonism in subjects undergoing catheter ablation has also been ineffective in preventing AF recurrences.

Lone atrial fibrillation - an overview

Atrial fibrillation (AF) sometimes develops in younger individuals without any evident cardiac or other disease. To refer to these patients who were considered to have a very favourable prognosis compared with other AF patients, the term 'lone' AF was introduced in 1953. However, there are numerous uncertainties associated with 'lone' AF, including inconsistent entity definitions, considerable variations in the reported prevalence and outcomes, etc. Indeed, increasing evidence suggests a number of often subtle cardiac alterations associated with apparently 'lone' AF, which may have relevant prognostic implications. Hence, 'lone' AF patients comprise a rather heterogeneous cohort, and may have largely variable risk profiles based on the presence (or absence) of overlooked subclinical cardiovascular risk factors or genetically determined subtle alterations at the cellular or molecular level. Whether the implementation of various cardiac imaging techniques, biomarkers and genetic information could improve the prediction of risk for incident AF and risk assessment of 'lone' AF patients, and influence the treatment decisions needs further research. In this review, we summarise the current knowledge on 'lone' AF, highlight the existing inconsistencies in the field and discuss the prognostic and treatment implications of recent insights in 'lone' AF pathophysiology.

The occurrence of cardiovascular disease during 5-year follow-up in patients with idiopathic atrial fibrillation

AIMS

Idiopathic atrial fibrillation (AF) may be an expression of as yet undetected underlying heart disease. We found it useful for clinical practice to study the long-term development of cardiovascular disease (CVD) in patients diagnosed with idiopathic AF.

METHODS AND RESULTS

Forty-one consecutive idiopathic AF patients (56 ± 10 years, 66% male) were compared with 45 healthy control patients in permanent sinus rhythm. Patients were free of hypertension, antihypertensive and antiarrhythmic drugs, diabetes, congestive heart failure, coronary artery or peripheral vascular disease, previous stroke, thyroid, pulmonary and renal disease, and structural abnormalities on echocardiography. Baseline characteristics and echocardiographic parameters were equal in AF cases and controls. During a mean follow-up of 66 ± 11 months, CVD occurred significantly more often in idiopathic AF patients compared with controls (49 vs. 20%, P= 0.006). Patients with idiopathic AF were significantly younger at the time of their first CV event compared with controls (59 ± 9 vs. 64 ± 5 years, P= 0.027), and had more severe disease. Multivariable Cox regression analysis revealed that age, a history of AF, and echocardiographic left ventricular wall width were significant predictors of CVD development.

CONCLUSION

Patients originally diagnosed with idiopathic AF develop CVD more often, at younger age, and with a more severe disease profile compared with healthy sinus rhythm control patients. The detection and treatment of CVD in an early stage could improve the prognosis of these patients. At present it seems prudent to regularly check idiopathic AF patients for the insidious development of CVD.

Lone atrial fibrillation: where are we now?

There is a growing pandemic of atrial fibrillation (AF), affecting nearly 2% of the general adult population. Atrial fibrillation is commonly associated with structural heart disease, and AF itself causes a sequence of complex processes of electrical, contractile, and structural remodeling of the atrial myocardium, which facilitate further AF progression. Nonetheless, AF may also affect individuals aged ≤ 65 years who have no evidence of associated cardiopulmonary or other disease, including hypertension; this is otherwise referred to as "lone" AF and is considered to have a generally favorable prognosis. The true prevalence of lone AF is unknown. Growing insights into the diversity of numerous mechanisms involved in the pathogenesis of AF, including acute atrial stretch, structural and electrophysiological alterations, systemic inflammation, oxidative stress, autonomic imbalance, genetic predisposition, and many others, and increasing recognition of novel risk factors for AF, including obesity, metabolic syndrome, subclinical atherosclerosis, sleep apnea, alcohol consumption, and endurance sports, suggest that apparently lone AF might not be so "lone" in many patients, which could have important prognostic and therapeutic implications. In this article, we summarize the current knowledge of epidemiology, etiopathogenesis, and pathophysiology of so-called lone AF and discuss the issues of long-term prognosis and management of patients who have an apparently lone AF.

Idiopathic atrial fibrillation revisited in a large longitudinal clinical cohort

AIMS

An age of 60 years is often used as cut-off for the diagnosis of idiopathic atrial fibrillation (AF). We investigated the importance of age and atrial size in patients with idiopathic AF and AF patients with isolated hypertension.

METHODS AND RESULTS

Out of 3978 AF patients in the Euro Heart Survey on AF with known follow-up, 119 (3%) patients had idiopathic AF. We disregarded age and atrial size when selecting idiopathic AF patients since the atria may enlarge by AF itself. For comparison, we selected 152 patients with isolated hypertension from the database. A total of 57 (48%) of the patients were older than 60 years. Persistent or permanent AF was more prevalent in the older idiopathic AF patients (34% in the age <60 vs. 66% in the age >60 years group, P= 0.002) but mean duration of known AF did not differ between these groups [310 days (inter-quartile range, IQR) 60-1827) vs. 430 days (IQR 88-1669), P= 0.824]. Left atrial size did not differ significantly in relation to age (1.50 ± 0.29 mm/kg/m² in the age <60 vs. 1.56 ± 0.31 mm/kg/m² in the age >60 years group, P= 0.742). Only two paroxysmal AF patients progressed to permanent AF. No cardiovascular events occurred during the 1-year follow-up. In contrast, strokes occurred in five patients (6%) with isolated hypertension despite similar clinical profile and comparable atrial size as idiopathic AF patients.

CONCLUSION

Idiopathic AF may present at advanced age and is even then not associated with significant atrial enlargement, AF progression, or an adverse short-term prognosis. In contrast, elevated blood pressure even when found in the absence of significant atrial remodelling, seems of prognostic importance.

Lone atrial fibrillation: what is known and what is to come

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia in adults, affecting >1% of general population. Atrial fibrillation is commonly associated with structural heart disease and is a major cause of significant cardiovascular morbidity and mortality. AF sometimes develops in a subset of young patients (e.g. aged ≤60 years), with no evidence of associated cardiopulmonary or other comorbid disease (including hypertension), and has been referred to as 'lone AF'. The latter generally has a favourable prognosis; the prognostic and therapeutic implications of an accurate identification of patients with truly lone AF (that is, truly at low risk of complications), if any, would be of the utmost importance. The true prevalence of lone AF is unknown, varying between 1.6% and 30%, depending on the particular study population. Nonetheless, novel risk factors for AF, including obesity, metabolic syndrome, sleep apnea, alcohol consumption, endurance sports, anger, hostility, subclinical atherosclerosis and others, have been increasingly recognised. Also, various underlying pathophysiological mechanisms predisposing to AF, including increased atrial stretch, structural and electrophysiological alterations, autonomic imbalance, systemic inflammation, oxidative stress and genetic predisposition, have been proposed. The growing evidence of these diverse (and numerous) pathogenic mechanisms and factors related to AF inevitably raises the question of whether 'lone AF' does exist at all. In this review article, we summarise the current knowledge of the epidemiology, pathophysiology, clinical course and treatment of patients with so-called 'lone AF' and outline emerging insights into its pathogenesis and the potential therapeutic implications of a diagnosis of lone AF.

Inhibition of the renin-angiotensin system for prevention of atrial fibrillation

Atrial fibrillation (AF) is a source of considerable morbidity and mortality. There has been compelling evidence supporting the role of renin-angiotensin system (RAS) in the genesis and perpetuation of AF through atrial remodeling, and experimental studies have validated the utilization of RAS inhibition for AF prevention. This article reviews clinical trials on the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) for the prevention of AF. Results have been variable, depending on the clinical background of treated patients. ACEIs and ARBs appear beneficial for primary prevention of AF in patients with heart failure, whereas they are not equally effective in hypertensive patients with normal left ventricular function. Furthermore, the use of ACEIs or ARBs for secondary prevention of AF has been found beneficial only after electrical cardioversion. Additional data are needed to establish the potential clinical role of renin-angiotensin inhibition for prevention of AF.

Lone AF - Etiologic Factors and Genetic Insights into Pathophysiolgy

Ever since atrial fibrillation (AF) was first recognized in young people (so called "lone" AF) over 4 decades ago, there has been increasing focus on determining the underlying pathophysiology of the condition. Although lone AF is presumed to be a highly heterogeneous disease, recent studies have identified novel risk factors such as inflammation, oxidative stress, endurance sports and genetics, for the arrhythmia. This monograph aims to highlight some of the recent advances in our understanding of the molecular pathophysiology of lone AF especially insight provided by contemporary genetic studies. These insights may provide novel therapeutic targets for treatment of this challenging arrhythmia in young patients.

Endothelin-1 as a predictor of atrial fibrillation recurrence after pulmonary vein isolation

BACKGROUND

A considerable rate of atrial fibrillation (AF) recurrence is one of the major limitations of pulmonary vein isolation (PVI). Although endothelin-1 (ET-1) is involved in atrial remodeling, it is unknown whether plasma ET-1 level before PVI can be used as a predictive factor for AF recurrence.

OBJECTIVE

The goal of this study was to clarify whether the plasma ET-1 level, before PVI, can be used as a predictive factor for AF recurrence after PVI.

METHODS

Fifty-one patients without structural heart disease who underwent PVI for symptomatic and drug-refractory paroxysmal/persistent AF were included in the study. Neurohumoral factors were measured, and transthoracic echocardiography was performed before and 6 months after each PVI. Mean left atrial (LA) pressure and arterial blood pressure (BP) were evaluated just before PVI. AF recurrence was detected by 12-lead electrocardiogram (ECG), Holter ECG, and event ECG monitor recordings, 3 to 6 months after PVI.

RESULTS

Among plasma levels of ET-1, atrial and brain natriuretic peptides, renin, angiotensin II, and aldosterone before PVI, only ET-1 was significantly higher in the recurrence group compared with the nonrecurrence group (2.15 +/- 0.51 vs. 1.65 +/- 0.35 pg/ml, P < .001). Both mean LA pressure and diastolic BP in the recurrence group were significantly higher than in the nonrecurrence group (mean LA pressure, 10 +/- 3 vs. 8 +/- 3 mm Hg, P < .01; diastolic BP, 82 +/- 11 vs. 71 +/- 12 mm Hg, P < .01). The plasma ET-1 level and mean LA pressure were correlative. Multiple logistic regression analyses showed that higher levels of plasma ET-1 and diastolic BP were significant prognostic predictors of AF recurrence 3 to 6 months after PVI (P < .01 and P < .05, respectively).

CONCLUSION

Our findings suggest that the plasma ET-1 level before PVI could be a crucial predictor of AF recurrence 3 to 6 months after PVI.

'Lone' atrial fibrillation: hunting for the underlying causes and links

The presence of lone atrial fibrillation presupposes the absence of structural heart disease, hypertension, or other known predisposing factors. However, several recent clinical and experimental data provide novel insights into the pathogenesis of lone atrial fibrillation. In addition, modern diagnostic techniques often reveal some previously unappreciated abnormalities. Therefore, the increasing recognition of potential causes and links sets the base for a more complete elucidation of its etiology in the near future. This concise review article discusses the contemporary advances in the understanding of this form of atrial fibrillation.