Heart rate variability in patients with atrial fibrillation and hypertension.

BACKGROUND: Atrial fibrillation (AF) and hypertension are independently associated with impaired autonomic function determined using heart rate variability (HRV). As these conditions frequently co-exist, we sought to determine whether AF would worsen HRV in hypertensive patients. DESIGN: We studied HRV in AF (and hypertension) (n = 61) and hypertension control group (n = 33). The AF (and hypertension) group was subdivided into permanent AF (n = 30) and paroxysmal AF (n = 31) and re-studied. Time-domain, frequency-domain and nonlinear measures of HRV were determined. Permanent AF group (n = 30) was followed up after 8 weeks following optimisation of their heart rate and blood pressure (BP). RESULTS: Time-domain and nonlinear indices of HRV were higher in AF (and hypertension) group compared to hypertensive controls (P ≤ .01). Time-domain and nonlinear indices of HRV were higher in permanent AF group compared to paroxysmal AF (P ≤ .001). Permanent AF was an independent predictor of HRV on multivariable analysis (P = .006). Optimisation of heart rate and BP had no significant impact on HRV in permanent AF. CONCLUSIONS: AF, independent of hypertension, is characterised with marked HRV and is possibly related to vagal tone. HRV is higher in permanent AF compared to paroxysmal AF suggesting evident autonomic influence in the pathophysiology of permanent AF. Modulation of autonomic influence on cardiovascular system should be explored in future studies.

Endothelial function in patients with atrial fibrillation.

Atrial fibrillation (AF) is the most common heart arrhythmia and is associated with poor outcomes. The adverse effects of AF are mediated through multiple pathways, including endothelial dysfunction, as measured by flow-mediated dilatation. Flow-mediated dilatation has demonstrated endothelial dysfunction in several conditions and is associated with poor outcomes including mortality, yet can be improved with medical therapy. It is thus a useful tool in assessing endothelial function in patients. Endothelial dysfunction is present in patients with AF and is associated with poor outcomes. These patients are generally older and have other co-morbidities such as hypertension, hypercholesterolaemia and diabetes. The precise process by which AF is affiliated with endothelial damage/dysfunction remains elusive. This review explores the endothelial structure, its physiology and how it is affected in patients with AF. It also assesses the utility of flow mediated dilatation as a technique to assess endothelial function in patients with AF. Key MessagesEndothelial function is affected in patients with atrial fibrillation as with other cardiovascular conditions.Endothelial dysfunction is associated with poor outcomes such as stroke, myocardial infarction and death, yet is a reversible condition.Flow-mediated dilatation is a reliable tool to assess endothelial function in patients with atrial fibrillation.Patients with atrial fibrillation should be considered for endothelial function assessment and attempts made to reverse this condition.

The influence of gender and place of residence on cardiovascular diseases and their risk factors. The Isfahan cohort study.

OBJECTIVE: To determine the impact of gender and place of residence on cardiovascular disease (CVD) events and related risk factors. METHODS: In a prospective cohort study, 6323 participants free of CVD (3255 women), with age of more than 35 years from 3 cities (Isfahan, Najafabad, and Arak) and their rural districts in central Iran were followed-up from 2001 to 2007. This study was carried out at the Cardiovascular Research Institute of Isfahan University of Medical Sciences, Isfahan, Iran. Endpoints were defined as fatal- and nonfatal myocardial infarction, sudden cardiac death, unstable angina and stroke that constituted CVD events. RESULTS: Subjects in the rural area had significantly better risk factor profile in terms of most CVD risk factors in both genders, but it was reverse for low density lipoprotein (LDL)-cholesterol in both genders, and smoking in men. Except for smoking, men had an overall better risk factor profile compared to women. The age and risk factors adjusted hazard ratio of living in rural area was 0.71 (95% confidence interval [CI]: 0.51-0.99) for men, and 0.63 (95% CI: 0.44-0.91) for women. The age of CVD occurrence was similar in men and women, and in rural and urban areas. Hypertension was the strongest predictor of these events except for rural men showing that high LDL-cholesterol was the strongest risk factor. CONCLUSION: The findings in this study documented differences in CVD risk factors affecting the occurrence of CVD events according to gender and place of residence. Such differences should be taken into account in future preventive public health strategies for CVD prevention.