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BACKGROUND Congenital heart disease (CHD) is a common heart condition which does considerable harm to the health of children and adolescents. CHD epidemiological characteristics of Tibetan children whose ages ranged from 4 to 18 years were investigated in Qinghai Province. METHODS A total of 32 578 Tibetan children, living at altitudes of 2535 m, 3600 m and 4200 m, were examined using a three-stage protocol: prescreening, rechecking and diagnosis using a color Doppler. The distribution of CHD at different altitudes was analyzed together with differences in occurrence according to age and gender. RESULTS A total of 235 CHD cases were discovered. The total prevalence of CHD was 7.21 per thousand. Prevalence of CHD has been shown to increase along with increase in altitude with 5.45 per thousand at an altitude of 2535 m, 6.80 per thousand at 3600 m and 9.79 per thousand at 4200 m. There were no statistically significant differences between the prevalence at 2535 m and 3600 m (chi(2) = 1.594, P > 0.05). However, there was a significant difference between the prevalence at 2535 m and 4200 m (chi(2) = 7.002, P < 0.01). Also, apparent differences existed between the prevalence at 3600 m and at 4200 m (chi(2) = 5.540, P < 0.05). There was no statistically significant difference in prevalence according to age at an altitude of 2535 m, but the rate of CHD increased significantly along with increasing age at 3600 m and 4200 m. The total prevalence ratio of children aged from 16 to 18 years was significantly higher than that of children from 4 to 7, and from 8 to 12 with chi(2) values of 10.79 (P < 0.005), and 5.60 (P < 0.05) respectively. Within the constituent ratio of CHD, the prevalence of atrial septal defect (ASD) was the highest at 39.10%, followed by the prevalence of ventricular septal defect (VSD) at 32.8% and patent ductus arteriosus (PDA) at 24.7%. Furthermore the proportion of the four categories of CHD varied at different altitude levels: at 2535 m, of those diagnosed with CHD, the prevalence rate of VSD was the highest at 43.5%, at 3600 m ASD was the highest at 42.8% and at 4200 m, PDA was the highest at 50.8%. CONCLUSION The epidemiological characteristics of CHD in Tibetan children may be associated with altitude levels.

The current theory of dyspnea perception presumes a multidimensional conception of dyspnea. However, its validity in patients with cardiopulmonary dyspnea has not been investigated.A respiratory symptom checklist incorporating spontaneously reported descriptors of sensory experiences of breathing discomfort, affective aspects, and behavioral items was administered to 396 patients with asthma, chronic obstructive pulmonary disease (COPD), diffuse parenchymal lung disease, pulmonary vascular disease, chronic heart failure, and medically unexplained dyspnea. Symptom factors measuring different qualitative components of dyspnea were derived by a principal component analysis. The separation of patient groups was achieved by a variance analysis on symptom factors.Seven factors appeared to measure three dimensions of dyspnea: sensory (difficulty breathing and phase of respiration, depth and frequency of breathing, urge to breathe, wheeze), affective (chest tightness, anxiety), and behavioral (refraining from physical activity) dimensions. Difficulty breathing and phase of respiration occurred more often in COPD, followed by asthma (R(2) = 0.12). Urge to breathe was unique for patients with medically unexplained dyspnea (R(2) = 0.12). Wheeze occurred most frequently in asthma, followed by COPD and heart failure (R(2) = 0.17). Chest tightness was specifically linked to medically unexplained dyspnea and asthma (R(2) = 0.04). Anxiety characterized medically unexplained dyspnea (R(2) = 0.08). Refraining from physical activity appeared more often in heart failure, pulmonary vascular disease, and COPD (R(2) = 0.15).Three dimensions with seven qualitative components of dyspnea appeared in cardiopulmonary disease and the components under each dimension allowed separation of different patient groups. These findings may serve as a validation on the multiple dimensions of cardiopulmonary dyspnea.