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Enhanced detection of left atrial spontaneous echo contrast by transthoracic harmonic imaging in mitral stenosis
1Cardiology Division, Yonsei Cardiovascular Center and Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea. jwha@yumc.yonsei.ac.kr
Insights
Transthoracic harmonic imaging (HI) significantly improves the detection of left atrial spontaneous echo contrast (SEC) in mitral stenosis (MS) patients. This novel technique enhances visualization of SEC, crucial for assessing thromboembolism risk.
Area of Science:
- Cardiology
- Medical Imaging
- Echocardiography
Background:
- Left atrial spontaneous echo contrast (SEC) indicates a higher risk of thromboembolism in mitral stenosis (MS) patients.
- Accurate detection and grading of left atrial SEC are vital for prognostic assessment in MS.
- Harmonic imaging (HI) is a novel echocardiographic technique with potential for improved image quality.
Purpose of the Study:
- To evaluate the utility of transthoracic noncontrast tissue harmonic imaging (HI) for detecting left atrial (LA) SEC in patients with MS.
Main Methods:
- Seventy-four MS patients underwent transthoracic echocardiography (TTE) using both fundamental imaging (FI) and HI modes.
- Transesophageal echocardiography (TEE) was used as a reference standard for grading LA SEC.
- A control group of 30 patients without LA SEC was included.
Main Results:
- TEE confirmed LA SEC in 73 out of 74 MS patients (mild in 35, severe in 38).
- Transthoracic fundamental imaging (FI) detected LA SEC in only 5 patients (6.8%).
- Transthoracic harmonic imaging (HI) detected LA SEC in 63 patients (86.3%), with 100% sensitivity for severe SEC.
Conclusions:
- Transthoracic harmonic imaging (HI) significantly improves the detection of left atrial spontaneous echo contrast (SEC) in patients with mitral stenosis (MS).
- HI offers superior sensitivity compared to fundamental imaging for identifying LA SEC, particularly severe cases.
Background:
Spontaneous echo contrast (SEC) of the left atrium is associated with increased risk of thromboembolism in patients with mitral stenosis (MS). The determination of the presence and severity of left atrial (LA) SEC is of prognostic importance in these patients. Harmonic imaging (HI), a novel echocardiographic technique that differs from conventional fundamental imaging (FI) in that it involves transmitting ultrasound at one frequency and receiving at twice the transmitted frequency, produces better endocardial border definition and myocardial opacification. However, there are no data about its value for the detection of LA SEC. The purpose of this study was to investigate the utility of transthoracic noncontrast tissue HI in the detection of LA SEC in patients with MS.
Methods:
Seventy-four consecutive patients with MS (49 women, mean age 51 years) underwent standard transthoracic echocardiography (TTE) in both HI and FI modes and transesophageal echocardiography (TEE) to determine the presence and severity of LA SEC. Left atrial SEC was graded by TEE as either mild (only seen at high gain) or severe (visible in the entire left atrium at normal gain control of the equipment). The control group comprised 30 patients randomly selected from patients who did not have LA SEC at the TEE examination.
Results:
Atrial fibrillation was found in 46 patients (62.2%). The mean mitral valve area and mean mitral gradient were 1.0+/-0.3 cm(2) and 8.2+/-4.1 mm Hg, respectively. Nine patients (12.2%) had episodes of systemic embolism; 8 had stroke, and 1 had peripheral embolism. Left atrial thrombus was found in 11 patients (14.9%) by TEE. Left atrial SEC was present in all but one patient by TEE (mild in 35 patients, severe in 38). Fundamental imaging with TTE, however, revealed LA SEC in only 5 (6.8%) of the 73 patients. In contrast, with HI, LA SEC could be detected in 63 (86.3%) patients. In the detection of severe LA SEC, the sensitivities of FI and HI were 13.2% (5/38) and 100% (38/38), respectively. Left atrial SEC was not observed in control subjects by either FI or HI.
Conclusions:
Transthoracic HI significantly enhances the detection of LA SEC in patients with MS.