Abstract-Hypertension is the most prevalent risk factor for incident atrial fibrillation (AF). Recently, even high normal blood pressures (BPs) have been established as predictive of AF in women. We aimed to study the long-term impact of upper normal BP on incident AF in a population-based study of middle-aged men. From 1972From to 1975From , 2014 Key Words: arrhythmia Ⅲ cardiac disease Ⅲ epidemiology Ⅲ hypertension Ⅲ men T he incidence of atrial fibrillation (AF) is increasing in the general population. 1-3 Currently, there is growing awareness of AF as a major health problem mainly because of its strong association with heart failure and stroke. 4 -6 Rhythm control strategies for sinus rhythm maintenance are unfortunately not optimal in clinical practice. 7,8 Therefore, additional knowledge of AF prevention by identifying possible treatable risk factors has important clinical relevance. 9,10 The Framingham Heart Study, as well as other populationbased cohort studies, has shown that arterial hypertension is a strong independent risk factor for AF. 8,[11][12][13][14] Furthermore, a recent study by Conen et al showed that even systolic and diastolic blood pressure (BP) within the nonhypertensive range was independently associated with AF in a large cohort of middle-aged women. 15 Another recent study from the prospective follow-up in the Framingham cohort demonstrated that pulse pressure, reflecting arterial stiffness, was the most important predictor of AF. 16 In our study cohort, we have previously established baseline systolic BP as a strong predictor of cardiovascular death, but potential association with AF has never been assessed. 17 In the present study, we aimed to test the long-term impact of systolic BP, in particular upper normal systolic BP, on the risk of developing AF in healthy middle-aged men. Second, we aimed to assess the associations between incident AF and diastolic BP and pulse pressure. From 1972From to 1975From , 2014 apparently healthy men aged 40 to 59 years from 5 governmental institutions in Oslo were included in a prospective cardiovascular survey after careful screening of health information. The presence of any of the following diseases caused primary exclusion: known or suspected coronary heart disease; diagnosed hypertension requiring drug treatment; diabetes mellitus; thyroid disorders; cancer; advanced pulmonary, renal, or liver Continuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz. Methods Study Population

Background-Low resting heart rate (HR) has been associated with atrial fibrillation (AF) in athletes. We aimed to study whether low HR at rest or during exercise testing was a predictor of AF in initially healthy middle-aged men. Methods and Results-A total of 2014 healthy Norwegian men participated in a prospective cardiovascular survey, including a standardized bicycle exercise test in 1972 to 1975. During ≤35 years of follow-up (53 000 person-years of observation), 270 men developed incident AF, documented by scrutiny of health charts in all Norwegian hospitals. Risk estimation was analyzed with Cox proportional hazard models. Low exercise HR after 6 minutes exercise on the moderate workload of 100 W (HR100W) was a predictor of incident AF. men with HR100W <100 beats per minute (n=260) were characterized by high physical fitness, low resting and low maximum HR, and they had 1.60-fold AF risk (95% confidence interval, 1.11-2.26) compared with men with HR100W ≥100 beats per minute when adjusted for age, systolic blood pressure, and physical fitness. Additional adjustment for relative heart volume slightly reduced the association. The subgroup of men (n=860) with hypertensive blood pressure measurements at baseline had the highest risk difference between low and high HR100W with hazard ratio 2.08 (1.19-3.45). Conclusions-Our data indicate that low exercise HR on a moderate workload is a long-term predictor of incident AF in healthy middle-aged men. Elevated baseline blood pressure substantially amplifies this risk. The present results suggest a relationship between increased vagal tone, high stroke volumes and incident AF, and particularly so in physically fit men. (Circ Arrhythm Electrophysiol. 2013;6:726-731.)Key Words: atrial fibrillation ◼ heart rate ◼ exercise test ◼ epidemiology ◼ men Received November 10, 2012; accepted June 17, 2013. From the Department of Cardiology, Oslo University Hospital, Ullevaal, Norway (I.G., P.T.S., K.E., K.G., S.E.K., H.A., J.B.); Center for Clinical Heart Research, Oslo University Hospital, Norway (I.G., H.A.); Faculty of medicine (I.G., P.T.S., K.G., S.E.K., H.A., J.E.), Department of Informatics, University of Oslo, Norway (K.L.); and Department of Cardiology, Oslo University Hospital, Rikshospitalet, Norway (G.E.).The online-only Data Supplement is available at http://circep.ahajournals.org/lookup/suppl/doi:10.1161/CIRCEP.113.000267/-/DC1. Correspondence to Irene Grundvold, mD, Department of Cardiology, Oslo University Hospital, Ullevaal, PB 4956 Nydalen, 0424 Oslo, Norway. E-mail UXIRGR@ous-hf.no Low Heart Rates Predict Incident Atrial Fibrillation in Healthy Middle-Aged MenIrene Grundvold, mD; Per Torger Skretteberg, mD; Knut Liestøl, PhD; Gunnar Erikssen, mD, PhD; Kristian Engeseth, mD; Knut Gjesdal, mD, PhD; Sverre E. Kjeldsen, mD, PhD; Harald Arnesen, mD, PhD; Jan Erikssen, mD, PhD;Johan Bodegard, mD, PhD Grundvold et al Heart Rate and Atrial Fibrillation 727hours. Resting BP was measured thrice manually to the nearest even 2 mm Hg with a calibrated mercury sphygmoman...

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There is no consensus on the definition of an exaggerated increase in systolic blood pressure (SBP) during exercise. The aim was to explore a potential threshold for exercise SBP associated with increased risk of coronary heart disease (CHD) in healthy men, using repeated exercise testing. 2,014 healthy Caucasian male employees were recruited into the Oslo Ischemia Study during early 1970s. At follow-up seven years later, 1,392 men were still considered healthy. A bicycle exercise test at 100W workload was performed at both visits. Cox regression analyses were performed with increasing cutoff levels of peak SBP during 100W workload (SBP100W) from 160 mmHg to 200 mmHg, adjusted for cardiovascular risk factors and physical fitness. Participants with SBP100W below cutoff level at both baseline and first follow-up were compared to participants with SBP100W equal to or above cutoff level at both visits. Compared to participants with SBP100W below all cutoff levels between 165-195 mmHg, CHD risk was increased amongst participants with SBP100W equal to or above cutoff at all levels. There was no evidence of a distinct threshold level for CHD risk, and the relation between SBP100W and CHD appears linear. When investigating exercise SBP at moderate workload measured at two exercise tests in healthy middle-aged Caucasian men, there is increasing risk of coronary disease with increasing exercise SBP independent of SBP at rest. The association is linear from the low range of exercise SBP and there is no sign of a distinct threshold level for increased coronary disease risk. Participants were divided into groups defined by SBP100W at Visit 1 and Visit 2 (Figure S1). Group 1 includes participants with SBP100W below cutoff level at both Visit 1 and Visit 2. Group 3 includes participants with SBP100W equal to or above cutoff level at both Visit 1 and 2, and Group 2 includes participants with SBP100W equal to or above cutoff level at only one of the two visits, regardless of which. To investigate the risk of CHD, we performed Cox regression analyses adjusted for age, resting SBP, total serum cholesterol, smoking status and family history of CHD. We also performed additional analyses adjusting for physical fitness. Physical fitness was defined as total workload during the exercise test measured in kilojoules divided by body weight. Due to the increases in cutoff levels, the number of participants in each group successively changed in each analysis, as Group 1 expanded and Group 3 diminished.