Hump Sign in the ST-Segment During Exercise Testing

 

Patient selection: subject undergoing exercise testing

 

The hump sign:

(1) a discrete upward deflection in the early portion of the ST segment

(2) may be seen best in II, III, aVF, V1 to V6

(3) occurs during the peak of the exercise testing

 

The ST segment often shows non-ischemic depression. The ST-segment depression may be associated with a false-positive exercise test.

 

Proposed pathophysiology: The combination of an atrial Ta wave with the ventricular ST electrical activity results in a depressed ST segment with a diphasic region early. The diphasic portion consists of a upward hump sign (with axis the same as the p wave) followed by a downward notch sign (with axis opposite to the p wave).

 

Interpretation:

• The presence of a hump sign indicates the presence of left ventricular diastolic dysfunction.