Yes, a prolonged QT-Interval could be an inherited condition and can lead to Arrhythmia. On the other hand, I had PVC's for many years and only now (I am 80 years old) do they occur at such short intervals that I personally (not a doctor) classified them as Arrhythmia and I have made an appointment with a cardiologist. But in your case he would have seen it on the ECG and told you.