Asthma, abbreviation for bronchial asthma, is one of the common chronic airways disease that threatens human health. Typical symptoms of asthma are recurrent wheezing, shortness of breath, chest tightness and cough, usually occurring at night or early morning. However, there are still some patients with only persistent clinical manifestations of chest tightness. Concerned about this group of patients, we presented a subgroup of bronchial asthma, namely, chest tightness variant asthma (CTVA). This asthma subgroup usually lacks asthma-specific clinical features such as wheezing, shortness of breath, wheezing, and therefore often misdiagnosed for a long time. In order to further understand the clinical characteristics, pathogenesis, and prognosis of patients with CTVA, we conducted a national multicenter observation study to further understand CTVA. Finally, we plan to clarify whether CTVA is a relatively independent asthma phenotype. Meanwhile, reducing misdiagnosis and perform an appropriate treatment of CTVA.

Inclusion Criteria:

1. all subjects agreed to participate, understand the project, observe the use of drugs, agree to follow-up, and signed informed consent;

2. the age of more than 14 and less 80 years old, gender and ethnicity are not limited;

3. the duration time was more than 6 months,and chest tightness was the only complaint, without breathing, short of breath, chronic cough;

4. no wheezing;

5. a diagnosis of asthma supported by one or more other characteristics:

   • bronchial provocation test positive;
   • improvement in forced expiratory volume at one second (FEV1) of more than 12% and 200 mL after inhaled salbutamol;
   • variability in diurnal peak expiratory flow (PEF) of more than 10% for one day during one week.

6. bronchodilator and glucocorticoid treatment is effective;

7. exclude the following diseases by the corresponding doctors: coronary heart disease, myocarditis, heart failure, GERD, neuromuscular disease, and mental disease.

Exclusion Criteria:

1. can not cooperate with related inspection or for other reasons;
2. patients with chronic obstructive pulmonary disease, interstitial pneumonia, active tuberculosis, community acquired pneumonia, lung cancer, bronchiectasis, cor pulmonale, pulmonary embolism, and accompanied with serious systematic disease (such as coronary heart disease, myocarditis, heart failure, gastroesophageal reflux disease, neuromuscular disease, etc);
3. history of drug abuse, alcohol abuse or anesthesia or with a history of mental illness (schizophrenia, obsessive-compulsive disorder, depression) and against personality, motivation, suspicious, or other emotional or mental issues that may affect participation in the study;
4. taking part in other drug clinical trial project, or drop out less than 3 months;
5. during pregnancy, lactation women;
6. obvious abnormal of High Resolution CT.

Patients with only symptom of chest tightness and bronchial provocation test positive according to eligibility criteria.