A 20-year-old college basketball player is brought to the university urgent care clinic after developing chest pain and palpitations during practice. There is no dyspnea or tachypnea. He denies family history of cardiac disease, and social history is negative for alcohol or drug use. Cardiac auscultation is unremarkable, and ECG shows frequent premature ventricular contractions (PVCs). Which of the following is the most appropriate next step in evaluation and/or management?