question: I am 69 years old.  On August 30, I passed out, was taken to the hospital, and had two other episodes.  I have chronic kidney disease with creatine around 2.0 .  I had anemia and hemoglobin was 7.9, was given two units of blood.  Also, had infection in my parotid gland.  I was in ICU 4 days and discharged in stable condition.  My doctor sent me to a cardiologist, who wants me to have a cardiac catherization.  I had no increase in cardiac enzymes and an ECHO in the hospital showed very mild valve leakage.  Is this invasive, risky procedure necessary.