<s>[INST] I am 68 yrs old in good health. Blood pressure normal & check it often I have had 3 dizzy spells in the last 2 weeks They only last a few seconds to 20 seconds I had hepatacellular cancer in 2010 and all is well& am checked every 6 mos What could be causing the dis shyness? [/INST] Symptoms you are describing are suggestive of presyncope.  Consult your cardiologist and get following tests done...24 hrs holder monitoring2 d echoHead up tilt testBP in supine and standing pisitionAnd autonomic function testing if needed. Hope my advice will help you.  Take care.  Don't forget to rate me. </s>