ECG of polymorphic ventricular premature beats

The ambulatory monitoring tracing demonstrates ventricular premature beats with 3 different morphologies, known as polymorphic ventricular premature beats; 1 ventricular couplet (2 successive premature beats) is also seen (arrow). The blocked P waves after the first and second premature beats (*) are due to concealed retrograde AV nodal conduction from the premature beat.