Anatomically ventricles are separated by a single muscular wall namely inter ventricular septum.But physiologically it has to contribute to both ventricular function.
How does IVS is able to achieve this ?
For the naked eye both ventricles appear to contract almost simultaneously , but there is an intrinsic delay , first the LV contracts , followed by about 70 milliseconds right ventricle generates the peak pressure. So the IVS is able to help in a sequential, & coordinated contractions.This is called ventricular interdependence. Please note pericardium also contributes to this .
Final message
The mechanical function of IVS is effectively and intelligently shared by both chambers. The electrical delay even in milliseconds is enough to facilitate this sharing .Such is the power of nature. From this concept it is obvious LV dysfunction can have an adverse effect on RV function & vice versa.Similarly any electrical delay( LBBB, RBBB ) can impact the septal function. Fortunately the myocardium has much reserve function , bundle branch blocks in isolation rarely result in serious consequences unless there is loss of associated muscle mass.
Dr.S.Venkatesan MD 
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