Hi, As you have mentioned that you had heart attack and also underwent coronary artery stenting (3 stents), there is likely possibility of compromised heart pumping (which can be assessed by 2DEcho, echocardiography by presence of regional wall motion abnormality and left ventricular ejection fraction, LVEF). Also you have aortic valve obstruction (stenosis) which you have mentioned as 95% blockage. Aortic valve stenosis is assessed by 2DEcho & color Doppler of heart by which we can know about valve size, pressure gradient generated across heart valve by obstruction, any concomitant leakage (regurgitation). You have to avoid situations that put extra work on heart. 1) Physical or mental stress, which causes extra demand of blood and oxygen supply to body, which need to be fulfilled by extra work by heart which leads to increase in heart rate increased oxygen requirement there by increased blood supply to heart. 2) High altitude: climbing to high altitude require physical exertion also oxygen content of air decreases with height, again at high altitude there is need for more oxygen by body and there by extra work on heart. In the presence of compromised heart pumping and significant aortic valve blockage heart can not generate adequate cardiac output (cardiac out put in simple term means blood volume pumped by heart in aorta per minute). In resting state cardiac output generated by such heart is sufficient to fulfill need for oxygen and blood of body. But when there is increased need for oxygen and blood supply of body, despite of extra work heart cannot generate adequate cardiac output, and there is development of heart failure (let ventricular failure) which manifest as shortening of breath, breathlessness (doe to lung conestion), there may be swelling over legs, chest pain (heart attack). Then what should you do 1) continue your blood thinning medicines, antiplatelets. 2) keep in control your blood pressure, diabetes, cholesterol levels if any abnormality there. 3) use of diuretics that help in removing extra water from body and avoid lung congestion. 4) use of medications like B blockers, ACEI/ARBs that help in preserving heart function. 5) there may be need for aortic valve surgery, dilatation (valvotomy) or replacement ( valvoplasty) depending on your symptomatology, pressure gradient across aortic valve, presence of concomitant aortic regurgitation. I think this information may be sufficient to solve your queries.