Blood Pressure Load: An Effective Indicator of Systemic Circulation Status in Individuals With Acute Altitude Sickness

Background: Acute high altitude (HA) exposure results in blood pressure (BP) variations in most subjects. Previous studies have demonstrated that higher BP is potentially correlated with acute mountain sickness (AMS). The BP load may be of clinical significance regarding systemic circulation status.Objectives: This study aimed to examine HA-induced BP changes in patients with AMS compared to those in healthy subjects. Further, we provided clinical information about the relationship between variations in 24-h ambulatory parameters (BP level, BP variability, and BP load) and AMS.Methods: Sixty-nine subjects were enrolled and all participants ascended Litang (4,100 m above sea level). They were monitored using a 24-h ambulatory blood pressure device and underwent echocardiography within 24 h of altitude exposure. The 2018 Lake Louise questionnaire was used to evaluate AMS.Results: The AMS group comprised more women than men [15 (65.2%) vs. 13 (28.3%), P < 0.001] and fewer smokers [4 (17.4%) vs. 23 (50.0%), P = 0.009]. The AMS group exhibited significant increases in 24-h BP compared to the non-AMS group (24-h SBP variation: 10.52 ± 6.48 vs. 6.03 ± 9.27 mmHg, P = 0.041; 24-h DBP variation: 8.70 ± 4.57 vs. 5.03 ± 4.98 mmHg, P = 0.004). The variation of mean 24-h cBPL (cumulative BP load) (mean 24-h cSBPL: 10.58 ± 10.99 vs. 4.02 ± 10.58, P = 0.016; 24-h mean cDBPL: 6.03 ± 5.87 vs. 2.89 ± 4.99, P = 0.034) was also obviously higher in AMS subjects than in non-AMS subjects after HA exposure. 24-h mean cSBPL variation (OR = 1.07, P = 0.024) and 24-h mean cDBPL variation (OR = 1.14, P = 0.034) were independent risk factors of AMS. Moreover, variation of 24-h mean cSBPL showed a good correlation with AMS score (R = 0.504, P < 0.001).Conclusions: Our study demonstrated that patients with AMS had higher BP and BP load changes after altitude exposure than healthy subjects. Excessive BP load variations were associated with AMS. Thus, BP load could be an effective indicator regarding systemic circulation status of AMS.

Atrial fibrillation detection in primary care during blood pressure measurements and using a smartphone cardiac monitor

Improved atrial fibrillation (AF) screening methods are required. We detected AF with pulse rate variability (PRV) parameters using a blood pressure device (BP+; Uscom, Sydney, Australia) and with a Kardia Mobile Cardiac Monitor (KMCM; AliveCor, Mountain View, CA). In 421 primary care patients (mean (range) age: 72 (31–99) years), we diagnosed AF (n = 133) from 12-lead electrocardiogram recordings, and performed PRV and KMCM measurements. PRV parameters detected AF with area under curve (AUC) values of up to 0.92. Using the mean of two sequential readings increased AUC to up to 0.94 and improved positive predictive value at a given sensitivity (by up to 18%). The KMCM detected AF with 83% sensitivity and 68% specificity. 89 KMCM recordings were “unclassified” or blank, and PRV detected AF in these with AUC values of up to 0.88. When non-AF arrhythmias (n = 56) were excluded, the KMCM device had increased specificity (73%) and PRV had higher discrimination performance (maximum AUC = 0.96). In decision curve analysis, all PRV parameters consistently achieved a positive net benefit across the range of clinical thresholds. In primary care, AF can be detected by PRV accurately and by KMCM, especially in the absence of non-AF arrhythmias or when combinations of measurements are used.

Effects of L-citrulline malate oral supplementation on post-exercise hypotension

Background: L-citrulline malate supplementation promotes an increase in oxide nitric metabolites, which are considered important mediators of peripheral vasodilation. Thus, the supplementation with this substance might maximize the duration and magnitude of post-exercise hypotension. Objectives: To investigate the hypotensive effect of L-citrulline malate supplementation following a single session of aerobic exercise in normotensives. Methods: Forty adults, normotensives, sedentary, were randomly assigned to one of the four experimental groups (control-placebo, control-Lcitrulline, exercise-placebo and exercise-Lcitrulline). All participants ingested a sachet with placebo or L-citrulline with malate (6 grams), both dissolved in water and the ingestion was made 120 minutes before starting the experimental session. The subjects performed 40 minutes of walk/run at 60-70% of reserve heart rate. For the control session, they remained seated in rest during 40 minutes. The blood pressure was taken in rest and every 10 minutes until complete 60 minutes after the experimental session. The ambulatory blood pressure device take the readings every 20 minutes (awake time) and each 30 minutes (sleep time) over the course of 24 hours. Results: L-citrulline malate supplementation associated to aerobic exercise promoted significantly reductions on systolic blood pressure when compared with control-placebo at 20 min (net change[NC]: 9.7 mmHg [P=0.010]), 40 min (NC: 12.7 mmHg [P=0.010]), 50 min (NC: 12.1 mmHg [P=0.012]), 60 min (NC: 9.0 mmHg [P=0.050]) and overall mean (NC: 7.8 mmHg [P=0.018]) post exercise. Conclusion: Acute L-citrulline malate supplementation might potentiate the post-exercise hypotension effects in normotensive subjects.