Generally, for valvular disease, severity of symptoms as well as echocardiographic findings and changes may require ohs.
For coronary artery disease
and dysrhythmia, again symptoms or in the absence of which, results of ekg, stress test
, and angiographic findings may suffice in decision-making. Sometimes, depending upon the age, risk, and findings, non-ohs may be a better alternative, e.g. Plasty.