Click on image to view larger version.
Figure 1 Continuous wave (CW) Doppler regurgitant jet in a study patient before (left) and after cardiac resynchronization therapy (CRT) (right). Maximal rate of left ventricular systolic pressure rise (LV+dP/dtmax) is estimated by measuring the time interval between 1 m/s and 3 m/s on the downslope of the CW Doppler spectrum (solid lines). Estimated LV+dP/dtmax rises from approximately 510 mm Hg/s (approximately 63 ms) to approximately 720 mm Hg/s (approximately 44 ms), and transmitral pressure gradient peak occurs earlier in systole (arrows). Duration of functional mitral regurgitation (excluding the presystolic component) decreases from 435 ms (OFF) to 382 ms (CRT).