<prompt> Which one of the following findings is indicative of compromised LV performance?increased left ventricular ejection time LVET; normal pre-ejection period PEP and normal QS2 durationPEPLVET ratio 0.35; shoened QS2 durationPEPLVET ratio 0.35; no change in QS2durationReduction in PEP, LVET, and QS2 duration  <response>: LV systole has the phases of pre-ejection isovolumic contraction and ejection. If total systole duration remains normal, but isovolumic contraction duration increases, it would mean the ejection time has reduced. It is indicative of a compromised LV performance. Exact measurement of the duration of isovolumetric ventricular contraction is done by using the following parameters: Total electromechanical systole QS2, Pre-ejection period PEP, and LV ejection time LVET These can be measured by recording: ECG for the QRS complex; the Q wave indicates sta of ventricular depolarization or electrical systole, Phonocardiogram to record hea sounds; 2nd hea sound will mark the end of systole, and Carotid pulse to record LVET, which is from the beginning of carotid pressure rise to the dicrotic notch. QS2 electromechanical systole; from the onset of QRS complex on ECG to the closure of semilunar valves - dicrotic notch on carotid pulse. PEP is calculated as Total electromechanical systole - ejection time PEP QS2 - LVET PEP represents the electrical depolarization and isovolumic contraction of LV, that occur before the systolic ejection. The ratio PEPLVET is normally about 0.35. If QS2 is normal but PEPLVET ratio has increased, it means pre-ejection period has increased and the ejection time is reduced; it indicates a compromised LV performance. 