An 85-year-old patient who was referred to our institute for mitral valve surgery was suspected of having severe mitral regurgitation. Upon assessment, the patient reported general fatigue, which might not have been related to VHD. Auscultation revealed a Levine grade 2/6 pan-systolic murmur at the apex, without any diastolic rumble or the third heart sound (S3).
Transthoracic echocardiography (TTE) displayed mitral valve prolapse (P3) and a high-echoic, vibrating structure attached to the mitral valve, suggestive of chordal rupture (Fig. 1a and Movie 1). M-mode echocardiography showed that this structure was regularly vibrating and produced a shaggy echo (Fig. 1b).
Transthoracic echocardiography in case 1. B-mode in parasternal long axis view. The arrow shows high echoic structure attached to the mitral valve [mitral valve prolapse (P3)]. M-mode in parasternal long axis view. The arrow shows vibration structure (shaggy eco). Color Doppler in parasternal long axis view. Yellow allows are showed color Doppler stripes. Color Doppler in apical 4-chamber view. Yellow arrows are showed color Doppler stripes. Ao: aorta, LA: left atrium, LV: left ventricle, RA: right atrium, RV: right ventricle
Color Doppler echocardiography revealed strong color Doppler signals in systole, mimicking severe MR in the left atrium in both parasternal long-axis and apical 4-chamber views (Fig. 1c, d and Movies 2, 3). This pattern was the same when different echocardiography machines, including iE33, Epic CVx (Phillips Medical System, Andover, MA, Netherlands) and Vivid E95 (GE Healthcare, Milwaukee, WI, USA) were used, making it difficult to conclusively determine the severity of MR.
Transesophageal echocardiography (TEE) also depicted the vibrating structure at the mitral valve and color Doppler stripes in the left atrium (LA), left ventricle (LV), and even outside the cardiac chambers (Fig. 2a, b and Movies 4, 5). Notably, the color Doppler signal in the LA was present below the high-echoic structure at the mitral valve but not above it. M-mode echocardiography showed a shaggy echo, while Color M-mode displayed a regular fine mosaic (stripe) emanating from just distal to the ruptured chorda (Fig. 2c, d).
Transesophageal echocardiography in case 1. B-mode in long axis view. The arrow shows high echoic structure attached to the mitral valve [mitral valve prolapse (P3)]. Color Doppler transesophageal echocardiography. Color Doppler stripes are visible on the annular side within the LA and LV, as well as in the RA and RV. (yellow arrows). M-mode in long axis view. The arrow shows vibration structure (shaggy eco). Color M-mode in long axis view. The arrow shows that color Doppler stripes appear just below the shaggy echo, whether inside or outside of the LV. Ao: aorta, LA: left atrium, LV: left ventricle, RA: right atrium, RV: right ventricle
Furthermore, TEE revealed MR that appeared to be moderate or greater in severity (Fig. 3a, b, and Movies 6, 7). Quantitative evaluation using the PISA (proximal isovelocity surface area) method on TEE estimated an effective regurgitant orifice area of 0.39 cm2 and a regurgitant volume of 58 ml. However, due to the eccentric nature of the MR jet and challenges in achieving optimal alignment of the ultrasound beam, these measurements may potentially underestimate the severity. Left ventriculography showed Sellers grade II MR (Fig. 4a, b and Movies 8, 9).
Transesophageal echocardiography showing moderate MR in case 1. Color Doppler transesophageal echocardiography (0 degree). Color Doppler transesophageal echocardiography (60 degree). LA: left atrium, LV: left ventricle
Left ventriculography showing Sellers grade II MR in case 1. right anterior oblique projection (RAO). left anterior oblique projection (LAO)
We hypothesize that the color Doppler stripes, caused by the vibrating high-echoic structure resulting from the ruptured chorda, are responsible for this artifact.
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