His dizziness and sweating after moving from air conditioning into the heat was likely a temporary reaction to the sudden temperature change, which can dilate blood vessels, especially while taking blood pressure medications like Telvas AM. Since his cardiologist evaluated him and found him stable, an urgent CT scan is likely not necessary right now. However, please seek immediate medical care if he develops new symptoms like weakness, numbness, difficulty speaking, or vision changes. For your peace of mind, you can consult his primary doctor or neurologist to see if a routine follow-up is appropriate.