For some insight: Ectopic heartbeats are small variations in an otherwise normal heartbeat that causes an irregular pulse. They may occur without an obvious cause and are usually harmless.
They can be associated with an imbalance of electrolytes in the blood caused
and it can be the result of a decrease in blood supply to the heart.
"Ectopic beats may be caused or made worse by excessive smoking, alcohol consumption, caffeine, certain medications such as stimulants, and some illicit drugs".
In adults, ectopic beats are common. Their causes should be investigated even if it turns out that no treatment is needed.
From what I remember, most ectopic beats are nothing to worry about. It's most common for them to occur on treadmill tests when it's tilted to give harder work and on cooling down. It is not usually a sign of heart disease. Some ectopic beats can be caused by a previous heart attack, but most need no treatment and the patient simply needs reassurance. Very rarely medication can be given if dizziness is a problem, beta blockers work best. I think your cardiologist is just checking things out to be on the safe side. Caffeine and alcohol are thought to be a catalyst to this condition, and smoking.