Blood pressure in the early 40s impacts left atrial function by speckle-tracking strain two decades later: data from the ACE 1950 Study

Abstract Background With higher age, the left atrial (LA) wall stiffens, giving rise to impaired reservoir function and a compensatory increase in contractile function. The exposure of systemic blood pressures (BP) through life on the left heart chambers may be an explanation, but long-term follow-up studies are lacking. LA phasic function can be quantified by echocardiographic speckle-tracking strain analysis and provide prognostic information in cardiovascular disease. Purpose To explore the impact of BP in the early 40s on LA function assessed by strain two decades later. Methods A total of 3,706 individuals born in 1950 and residing in Akershus County, Norway, were included in the Akershus Cardiac Examination (ACE) 1950 Study. Baseline examinations were conducted between 2012-2015 and included echocardiography. Of those with available echocardiographic LA strain analyses, 2,399 participants had demographic and clinical data available from the Age 40 Program, a cardiovascular health survey performed when the participants were 40 years old. We assessed the impact of BP at age 40 on LA strain two decades later. Differences in LA reservoir (LASr) and contractile strain (LASct) between systolic (<120, 120-140 and >140mmHg) and diastolic (<70, 70-90, and >90mmHg) BP groups were assessed by ANOVA. Linear regression analyses were performed using BPs as continuous variables. Results Mean age of the 2,399 participants was 40.1±0.3 years at the time of the Age 40 program, and 63.9±0.6 years at the time of the ACE 1950 baseline examination. At age 40, 20.8% of participants had BP ≥140/ ≥90mmHg or used antihypertensive medication. Mean LASr was 35.1±9.2%, while mean LASct was 17.7±5.6%. LASr did not differ significantly between groups of systolic or diastolic BP. LASct, however, showed a statistically significant increase from lower to higher groups of both systolic and diastolic BP (Figure). In linear regression analyses, no associations were found between BPs and LASr, but systolic and diastolic BPs were both significantly associated with LASct (Table). The associations between BPs and LASct remained significant after adjustment for sex, BMI, daily smoking, resting heart rate and hypertension at age 40 (Table). Conclusions Higher systolic and diastolic BP in the early forties were associated with increased LA contractile function two decades later, but no significant changes in LA reservoir function were detected. This indicates contractile function as an early marker of subtle LA dysfunction.Figure.Table.