Premature ventricular contractions occur even in people who are in perfect health. As long as they are infrequent and asymptomatic and do not occur in someone who already has some type of heart disease, they are not a cause for concern.
Your doctor wanted the extra-long ECG just to make sure that the PVC was an isolated occurrence. Nothing more needs to be done.
PVCs become somewhat more common with age, even in healthy people, but since they are too infrequent to affect heart function or circulation, they still are not a problem.
On the other hand, if you had a history of heart attack or something, then the PVCs would have to be closely monitored.