Ventricular Escape/Rhythm

Ventricular escape rhythms occur when the faster pacemakers do not supply conduction to the His-Purkinje system at a rate greater than the ventricular pacemakers. This usually occurs with a complete heart block. A ventricular escape rhythm is defined by a wide complex (>120ms) rhythm at a rate 20-40bpm without supraventricular association (ie not associated with P waves). Patients are often quite symptomatic and may be unstable. It is differentiated from a junctional bradycardia due to the wide QRS complexes. The origin of the escape can be determined by the pattern of the QRS complex as they commonly take the form of a right bundle branch block or left bundle branch block. If a right bundle branch block morphology is present, the ventricular pacemaker originates in the left ventricle (and vice versa).

Examples:

Further Reading:

https://litfl.com/ventricular-escape-rhythm-ecg-library/