There will be problems in Ecg and exho only when Heart disease is at an advanced stage . They can be normal in early stages of heart blockage . The test used to detect the early stage is stress test most comply Lt TMT. Even this has its limitations as it’s a indirect way to test Heart. The only direct way to rule out Heart blockage is coronary angiogram . But that needs to be done only is there is some problem in Ecg exho or tmt. It’s not required to be done just to be sure

Yes there can be. Sometimes pts with coronary artery disease can have both normal.