A premature atrial contraction (PAC) occurs when a ... AV node is still refractory), a non-sinus P wave will be seen that is not followed by a QRS complex (non-conducted). There are four main ...

There are four main characteristics of PACs: Premature, occurring earlier than ... or the ectopic PR interval will be prolonged. The ECG will show a premature, ectopic P wave and then no QRS ...