Orthostatic hypertension frequently occurs in AF patients
There appears to be an association between orthostatic hypertension (OH) and atrial fibrillation (AF), according to a study suggesting that such association potentially reflects the role of the autonomic nervous system (ANS) in both AF and OH.
The study used data from the first wave of The Irish Longitudinal Study on Ageing, including a total of 4,408 participants aged ≥50 years. Beat-to-beat blood pressure was measured during active stand lasting 110 seconds. OH, which was defined as a fall in systolic blood pressure (SBP; ≥20 mmHg) or in diastolic blood pressure (DBP; ≥10 mmHg), was assessed at 30, 60 and 90 seconds. Initial OH was evaluated as a drop in SBP ≥40 mmHg or a drop in diastolic BP≥20 mmHg.
Of the participants, 101 had AF. Logistic regression analysis showed that compared with those without the condition, individuals with AF were more likely to have OH at 30 seconds (odds ratio [OR], 1.95; 95 percent CI, 1.24 to 3.06) and at 60 seconds (OR, 2.13; 1.18 to 3.87), as well as initial OH (OR, 1.81; 1.21 to 2.70).
The association seen between initial OH and OH at 30 seconds remained significant despite adjustment for potential confounders such as age, sex, baseline heart rate, education, blood pressure, smoking, frailty, beta blocker use, antihypertensive use and number of cardiovascular (CV) conditions.
Age-related changes in CV structure and function potentially explain the association between AF and OH, independent of comorbidities such as ischaemic heart disease. Another explanation is the ANS, which plays a role in the pathogenesis of both AF and OH. Via the baroreceptors, the ANS controls initial restoration of BP on stand. [Circulation 2003;107:139–46]
A recent study suggests that AF is related to the impairment of the baroreflex, and repair of sinus rhythm improves baroreflex gain. This could explain the strong association between initial OH and AF observed in the present investigation, researchers said. [J Am Heart Assoc 2016;5:e002997]
Findings of the present study has clinical implications, including a potential increased risk of falls and syncope. There is evidence suggesting an association and AF and falls, and the coexistence of OH could further increase the risk of falls, researchers added.
Future studies should analyse baseline heart rate variability and baroreflex sensitivity to further explore the relationship between AF and OF, they said.