Ashman Phenomenon

Definition

Definition of Ashman Phenomenon
Ashman phenomenon is an aberrant ventricular conduction due to a change in QRS cycle length. In 1947, Gouaux and Ashman reported that in atrial fibrillation, when a relatively long cycle was followed by a relatively short cycle, the beat with a short cycle often has right bundle-branch block (RBBB) morphology. This causes diagnostic confusion with premature ventricular complexes (PVCs). If a sudden lengthening of the QRS cycle occurs, the subsequent impulse with a normal or shorter cycle length may be conducted with aberrancy.

Symptoms

Symptoms of Ashman Phenomenon
These symptom for Ashman phenomenon:

1. Ashman
2. Aberrant
3. Ventricular
4. Conduction
5. Beat
6. Ending
7. Cycle
8. Atrial

Causes

Causes of Ashman Phenomenon
It occurs because the duration of the refractory period of the myocardium is proportional to the R-R interval of the preceding cycle. A short R-R interval is associated with a shorter duration of action potential and vice versa. A long R-R cycle will prolong the ensuing refractory period, and if a shorter cycle follows, the beat terminating the cycle is likely to be conducted aberrantly. Because the refractory period of the right bundle branch is longer than the left, the right bundle will still be in the refractory period when the supraventricular impulse reaches the His-Purkinje system, resulting in a complex with right bundle branch morphology.

Diagnosis

Diagnosis of Ashman Phenomenon
The diagnosis of Ashman phenomenon is made using ECG evaluation findings. Patients may be asymptomatic or may have symptoms of the underlying cardiac condition.

Treatment

Treatment of Ashman Phenomenon
No treatment is needed for isolated complexes. Treat the underlying cardiac condition as appropriate.

Prognosis

Prognosis of Ashman Phenomenon
Clinically, it is often asymptomatic by itself and considered benign in nature.

Prevention

Prevention of Ashman Phenomenon
Consult with your doctor.