My Husband Is Having A Diagnostic Heart Cath Next Week

My husband is having a diagnostic heart cath next week - no symptoms but did have a sl iregular EKG several months ago and had rheumatic fever as a child- stress test completed but did show a sl artifact in circumflex artery and cardiologist wants to check it out. My husband is a Vietnam vet with exposure to agent orange- hence the diabetes which started about 15 yrs ago. He is a farmer and very physically active with no signs of SOB or chest pain with heavy lifting. WE monitor his B/p and his last one was 135/75 in office and always is lower at home monitioring. His cardiologist wants him to start Toprol XL 25 but my husband is very reluctant after reading the siding effects esp the dizziness and brain fog. He drives big tractors and equipment and it seems to us taking that med is just a recipe for disaster. he has never been able to take statins also because of severe muscle pain and brain fog and his cholesterol is around 165. Is there an advantage to taking Toprol before a cardiac cath and if so what? A concerned RN wife