Amlodipine can cause palpitations and reflex tachycardia, or rebound fast heart beat. This side effect is usually dose-related. The higher the dose, the more likely the patient is to have these effects. You should discuss your concerns about the amlodipine with your doctor. Knowing your complete medical history, your doctor would best be able to determine if your irregular heartbeat was a result of taking the amlodipine.