Hypertension and atrial fibrillation with emphasis on prevention

Trajectories of Cardiovascular Risk Factors and Incidence of Atrial Fibrillation Over a 25-Year Follow-Up: The ARIC Study (Atherosclerosis Risk in Communities)

BACKGROUND

Timing and trajectories of cardiovascular risk factor (CVRF) development in relation to atrial fibrillation (AF) have not been described previously. We assessed trajectories of CVRF and incidence of AF over 25 years in the ARIC study (Atherosclerosis Risk in Communities).

METHODS

We assessed trajectories of CVRF in 2456 individuals with incident AF and 6414 matched control subjects. Subsequently, we determined the association of CVRF trajectories with the incidence of AF among 10 559 AF-free individuals (mean age, 67 years; 52% men; 20% blacks). Risk factors were measured during 5 examinations between 1987 and 2013. Cardiovascular events, including incident AF, were ascertained continuously. We modeled the prevalence of risk factors and cardiovascular outcomes in the period before and after AF diagnosis and the corresponding index date for control subjects using generalized estimating equations. Trajectories in risk factors were identified with latent mixture modeling. The risk of incident AF by trajectory group was examined with Cox models.

RESULTS

The prevalence of stroke, myocardial infarction, and heart failure increased steeply during the time close to AF diagnosis. All CVRFs were elevated in AF cases compared with controls >15 years before diagnosis. We identified distinct trajectories for all the assessed CVRFs. In general, individuals with trajectories denoting long-term exposure to CVRFs had increased AF risk even after adjustment for single measurements of the CVRFs.

CONCLUSIONS

AF patients have increased prevalence of CVRF many years before disease diagnosis. This analysis identified diverse trajectories in the prevalence of these risk factors, highlighting their different roles in AF pathogenesis.

Hypertension accelerates the 'normal' aging process with a premature increase in left atrial volume

Hypertension (HT) is associated with left ventricular (LV) diastolic dysfunction and consequent left atrial (LA) dilatation. We investigated changes in LA size and phasic function by decade in patients with HT. Patients with mild or moderate HT (n = 122) were compared with a case controlled normal cohort (blood pressure <140/90 mm Hg). Biplane LA maximum, minimum, and pre 'a' wave volumes were measured; LA filling, passive emptying, and active emptying volumes and fractions were calculated. Transmitral inflow and pulsed wave mitral annular tissue Doppler velocity were measured as expressions of LV diastolic function. The HT group had larger LA maximum volumes compared with normal controls for all decades until the 8th decade. Subjects with HT in decade 4 had LA maximum volume similar to that of normal controls from decade 8 (27.8 ± 4.3 mL/m(2) vs 25.6 ± 6.1 mL/m(2) respectively, P = .22). Active emptying volume and fraction were higher in the HT group across all decades, while there was no difference between the HT and normal groups for passive emptying volume. LV mass and E/E' ratio were significantly higher across all decades in the HT group. HT alters atrial dynamics significantly, with resultant increased LA volume and active emptying volume consequent to altered LV diastolic function. HT 'accelerates' the normal aging process with patients as early as decade 4 having similar LA size to that of normal controls in decade 8. This premature increase in LA volume may result in the future development of atrial fibrillation in HT patients.