Author + information
- Liu Xi and
- Lan Huang
We aimed to observe the alterations of right heart function by different altitudes and time phase, explore its roles in AMS and try to provide new clues and direction in clinical diagnosis, treatment and prevention for AMS.
The echocardiography examinations were performed by ultrasonography using the S5-1 cardiac probe (CX50, Philips, USA) by a senior technician. Most of the valuable parameters have been measured including right atrial diameter (RA), right ventricular end-diastolic diameter (RV), pulmonary artery (PA), pulmonary acceleration time (AT), tricuspid blood flow velocity E peak, tricuspid blood flow velocity peak A, the right ventricular outflow tract blood flow to the end time (b), tricuspid blood flow velocity at the a peak termination to the next new Tung Chau tricuspid blood the velocity E peak time interval (a) ECG R-wave peak to the right ventricular outflow tract ejection terminate at the time interval (c). Each parameter has been measured four consecutive cardiac cycles. Myocardial performance index (MPI) Tei index, mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVRTot), blood flow velocity in the tricuspid peak E∖A peak were calculated according the parameters abovementioned.
The AMS was diagnosed by Lake Louise international diagnostic criteria including the follow five symptoms: headache, dizziness, gastrointestinal symptoms, sleep difficulties and fatigue weakness.
Among 264 subjects who rapidly ascended to 3700m high altitude, the incidence of AMS was 25.8% (68 out of 196). Compared with plain, basic follow-up observations of 264 subjects' radical plateau 24h right heart function parameters variation is consistent with the findings in the first chapter. Enter the altitude of 3700m plateau 24h within the E/A ratio (P <0.05) reduced significantly, while Tei index, PVR, mPAP was increased significantly (all P values were less than 0.05). Tei index was higher (P <0.05) in AMS group than that in Non-AMS group, E/A ratio was lower (P <0.05) in AMS group than that in Non-AMS group. However, there were no significant differences inPVR, mPAP between AMS and Non-AMS groups.
1. The hypobaric hypoxic environment of high altitude would lead to a series of changes in right ventricular functions mainly reflected in increase of systolic function, reduction of diastolic function, as well as increase of right ventricular afterload.
2. Although there was no significant increase of right ventricular stroke work when exposing to the higher elevations after temporary adaption at 3,700m, yet the diastolic function degraded gradually, indicating that the body would initially enter into the acclimatization stage with the extension of stay in high-altitude hypoxic environment.
3. The occurrence and symptom severity of AMS (Acute Mountain Sickness) were certainly associated with the related right ventricular function indexes of Tei index and E/A ratio, which were also available for prediction and screening susceptible populations.