TAPSE the most celebrated RV function index misses significant Right Ventricular (RV) dysfunction in an estimated 30 to 50% of patients. ( when relying solely on it).It fails to detect underlying impairment because it only measures the longitudinal shortening of the RV base, largely ignoring global chamber contraction.
Mechanism attributed to the unreliability of TAPSE
- Ventricular Interdependence: The RV motion is influenced by left ventricular function by the shared IVS contraction.
- Chronic Volume or Pressure Overload: Conditions like severe tricuspid regurgitation or pulmonary hypertension cause the RV to alter its contraction geometry. This leads to “pseudo-normalization, of TAPSE” it remains >1.7 cm despite dysfunction.
- Post-Cardiac Surgery: In patients who have undergone procedures involving pericardiotomy, TAPSE often drops drastically as post pericardiotomy the RV radial function exccedds longitudinal
- Loading Dependency : TAPSE is highly influenced by preload and afterload conditions.
The following table summarises the various components and it’s contribution to RV contractility.
*Contrary to the popular belief, there is overlap between free wall contraction and longitudinal contraction. In fact, there is no clear definition for RV free wall. Logic tells us, any part of RV which is not formed by IVS can be considered free.
*Importantly, Longitudinal contraction has a two components free wall as well as a septal axis. TAPSE measures only lateral or free wall component of longitudinal function. It is less influenced by septal long axis function.
*The long axis function of RV is influenced indirectly by the LV function also as both AV valves are attached to same ring.
*If we want to assess pure RV function the best index is RV free wall circumferential or radial contraction or strain.
*In various clinical situations like PH or acute pulmonary embolism the pressure distribution is non-uniform making the assessment of RV function difficult. Fractional shortening of area is a fair index.RV wall motion abnormality can be subtle yet a serious marker of RV dysfunction.
Final message
RV function assessment is complex and often incomplete. The habit of relying only on TAPSE, is not a high quality scientific practice.
Postamble : Apart from the contractile function, we don’t know at what RV pressure RV begins to dilate. This is different in acute vs chronic elevation. We also don’t know which patient will show RV hypertrophy, and which group prefers dilation. May be, all these are academic and has little significance at the bedside. However understanding this is essential to assess the response to RV inotropes and newer RV assist devices.
Reference
Note the changing TR velocity implying severe RV contractile dysfunction.
Dr.S.Venkatesan MD 