先天性双孔二尖瓣畸形的彩色多普勒超声心动图诊断

目的通过总结分析先天性双孔二尖瓣畸形(DOMV)的超声表现,探讨彩色多普勒超声心动图的诊断价值.方法分别对7例先天性双孔二尖瓣畸形进行常规心脏检查,重点观察二尖瓣短轴切面、心尖四腔和两腔切面及胸骨旁左室长轴切面,观察瓣口形态、瓣膜回声、血流动力学情况及有无合并其他心血管畸形,并与手术比较.结果7例患者完全型2例,不完全型5例.二尖瓣中-重度反流2例,轻-中度反流3例,轻度狭窄伴轻度反流1例,无狭窄及反流1例.伴乳头肌发育异常1例,伴主动脉瓣二叶瓣畸形合并主动脉瓣赘生物形成1例.3例经手术证实.结论彩色多普勒超声心动图可以准确诊断先天性双孔二尖瓣畸形,并了解其血流动力学改变,是临床诊断的首选方法.     

超声心动图诊断先天性双孔二尖瓣畸形

目的应用彩色多昔勒超声心动图探讨双孔二尖瓣畸形。 方法Philips Sonos-4500及IE-33彩超仪器，探头频率2．5～4MHz，对5例患者进行常规检查，观察二尖瓣口形态、血流动力学改变及有无其它心脏畸形。 结果5例双孔二尖瓣中完全桥型3例，不完全桥型2例，2例伴有二尖瓣关闭小全，1例伴有二尖瓣狭窄，全部病例均合并其它心脏畸形。3例经手术证实。 结论彩色多普勒超声心动图是诊断双孔二尖瓣畸形简单、可靠的方法。     

双孔二尖瓣畸形复杂型的超声诊断

目的;探讨二维、彩色多普勒超声（２ＤＥ,ＣＤＦＩ）诊断双孔二尖瓣（ＤＯＭＶ）合并心脏其它畸形的作用。方法与结果：使用二维,彩色,脉冲及连续多普勒超声检查了６例复杂型ＤＯＭＶ,经与手术结果对照,４例ＤＯＭＶ合并部分型房室通道,２例分别伴有重度二尖瓣狭窄和关闭不全。手术前超声提示ＤＯＭＶ４例,漏诊２例,心内其它异常均诊断正确。结论：２ＤＥ、ＣＤＦＩ可准确诊断ＤＯＭＶ,漏诊原因与检查者对ＤＯＭＶ认识不足     

实时三维超声心动图诊断先天性双孔二尖瓣畸形的初步研究

目的探讨实时三维超声心动图(RT-3DE)观察先天性双孔二尖瓣畸形(DOMV)的应用价值。方法5例先天性DOMV患者,在常规二维超声心动图基础上,应用RT-3DE实时显像、全容积显像及彩色成像模式,观察畸形二尖瓣立体形态及血流动力学改变。结果5例先天性DOMV中,3例合并部分型房室间隔缺损,2例为单纯性双孔二尖瓣;2例合并有瓣裂,无瓣裂者3例;5例患者均伴有不同程度的二尖瓣关闭不全(中-重度3例,轻度1例,功能正常1例)。术前二维超声提示3例DOMV,漏诊2例(其中1例术后复查时提示)。实时三维超声提示4例DOMV,1例术前未行实时三维超声检查,术后复查时提示。结论与二维超声心动图比较,实时三维超声心动图能更全面、立体地显示二尖瓣的空间结构,提高对DOMV诊断的准确性,可作为传统二维超声心动图的重要补充。     

二尖瓣返流病人收缩期左房内前向性血流的研究

本研究应用彩色多普勒超声心动图检测了31例收缩期左房内前向性血流。将脉冲多普勒取样容积置于二尖瓣口左房侧,在与负向性返流相并行的一侧出现收缩期正向性血流频谱时,定为前向性血流,彩色多普勒血流显示为红色血流。全部病人均经心血管造影及/或手术证实。结果表明,收缩期左房内前向性血流是由于大量、高速、偏心的血流在左房内折返形成漩涡而产生,此血流常发生于连枷样二尖瓣病人,阳性率为93.5％,也可以发生于非FMV严重的二尖瓣返流病人。     

Prediction of Optimal Atrioventricular Delay in Patients with Implanted DDD Pacemakers

In patients with an implanted DDD pacemaker (PM), the atrial contribution may be interrupted by too short an atrioventricular (AV) delay, and filling time may be shortened by too long an AV delay. The AV delay at which the end of the A wave on transmitral flow coincides with complete closure of the mitral valve may be optimal. The subjects were 15 patients [70.3+/-12.3 (SD) years old] with an implanted DDD PM. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. Transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 msc. When the AV delay was set at 155+/-26 ms, the end of the A wave coincided with complete closure of the mitral valve. When the AV delay was prolonged 25, 50, 75, and 100 ms from this AV delay, the interval between the end of the A wave and complete closure of mitral the valve was prolonged 16+/-5, 39+/-6, 65+/-4 and 88+/-5 ms, respectively (r = 0.97, P<0.0001) and diastolic mitral regurgitation was observed during this period. Thus, the optimal AV delay may be predicted as follows: the slightly prolonged AV delay minus the interval between the end of the A wave and complete closure of the mitral valve. When the AV delay was set at 215 ms, there was a significant positive correlation between the predicted optimal AV delay (166+/-23 ms) and the optimal AV delay (CO: 161+/-26 msec, r = 0.93, P<0.0001, PCWP: 161+/-28 msec, r = 0.95, P<0.0001). In conclusion, optimal AV delay can be predicted by this simple formula: slightly prolonged AV delay minus the interval between end of A wave and complete closure of mitral valve at the AV delay setting.     

Simple method for estimating regurgitant volume with use of a single radius for measuring proximal isovelocity surface area: an in vitro study of simulated mitral regurgitation.

The proximal isovelocity surface area (PISA) color Doppler method with use of a hemielliptic formula is reported to be accurate for quantitating regurgitant volume (RV). However, this formula ideally requires the measurement of 2 or 3 radii and therefore is not widely used clinically. The purpose of this in vitro study was to derive a simple PISA formula for estimating RV with use of a single radius axial to the valve orifice and to compare it with the clinically used single-radius hemispherical formula (2 x pi R(2) x AV x TVI/Vp), where AV is the apparent color Doppler aliasing velocity, R is the PISA color Doppler aliasing radius, TVI is time-velocity integral of the jet by continuous wave Doppler, and Vp is the peak velocity of the jet by continuous wave Doppler. Pulsatile flow studies were performed across a convex curvilinear surface, which more closely approximates the shape of the mitral valve than does a planar surface. Pulse rates (60 to 80 bpm), peak flow velocities (4.0 to 6.0 m/s), and regurgitant orifice areas (0.2 to 1.0 cm(2)) were varied to simulate mitral regurgitation. The AVs were varied from 11 to 39 cm/s, and a single PISA aliasing radius was measured at each AV. Excellent linear correlations were obtained between the PISA radius and the actual RV measured with use of a beaker (r = 0.94 to 0.97, P <.0001). A series of simplified formulas was derived from the regression line of the PISA radius versus the RV. For example, with an AV of 21 cm/s, RV was estimated by a simplified PISA formula (where RV[mL] = 10 x R [mm] - 30) with an accuracy of 3.3 +/- 6.3 mL versus -20.3 +/- 8.7 mL for the standard single-radius PISA method (P <.0001). By using the standard single-radius hemispherical PISA formula, RV was underestimated if the radius was <20 mm. By using simplified regression equations, the PISA radius accurately estimated RV at a PISA radius <20 mm. Clinical studies are necessary to validate this concept.     

Left atrial systolic antegrade flow in patients with mitral regurgitation: a pulsed Doppler sign displayed by color flow imaging

Twenty-two patients with severe mitral regurgitation were observed to have turbulent systolic antegrade flow on pulsed Doppler mapping of the left atrium. All were studied by color flow imaging to delineate the mechanism of this peculiar flow. Pulsed Doppler findings of an eccentric regurgitant flow in one side, an antegrade systolic flow with slightly delayed onset in the other side, and a low velocity flow near the posterior wall, were consistant with the theory of a large eccentric regurgitant jet swirling in the left atrium. Color flow imaging confirmed this mechanism in all patients. Nineteen patients had flail mitral valve with a positive predictive value of 86%. The other three patients had deformed rheumatic mitral valve. The severity of mitral regurgitation was confirmed in all 16 patients studied by left ventricular cineangiography. We have shown that the antegrade systolic left atrial flow is the result of the swirling of a large regurgitant eccentric jet, is commonly observed with flail mitral valve, can occur in patients with deformed rheumatic mitral valve without flail leaflet, and most significantly indicates the presence of severe mitral regurgitation.     

A comparison of flow convergence with other transthoracic echocardiographic indexes of prosthetic mitral regurgitation.

Prosthetic shadowing of the left atrium may prevent detection of mitral regurgitation during transthoracic echocardiography. In 60 patients with mitral valves, Carpentier-Edwards (n = 20), St. Jude (n = 22), and cage-ball (n = 18), we blindly evaluated the accuracy of three transthoracic Doppler signs of significant (> 2+) mitral regurgitation: (1) color Doppler flow convergence, (2) a color Doppler jet of significant regurgitation in the left atrium, and (3) an intense continuous wave Doppler signal. All 60 patients had transesophageal echocardiography, 26 had cardiac catheterization, and 28 had surgery. The sensitivity and specificity of flow convergence for significant regurgitation by transesophageal echocardiography was 73% and 70%, respectively, compared with 33% and 93% for left atrial color Doppler, and 15% and 97% for continuous wave Doppler. The sensitivity of flow convergence in Carpentier-Edwards, St. Jude, and cage-ball valves was 80%, 73%, and 67%, respectively; whereas the sensitivity of left atrial color Doppler was 70%, 27%, and 0%, and the sensitivity of continuous wave Doppler was 33%, 0%, and 13%. Flow convergence was the only sign of significant regurgitation in 12 of 30 patients (40%); 10 of these patients had mechanical valves. We conclude flow convergence is a more sensitive, though less specific, predictor of significant mitral regurgitation than color Doppler, spatial mapping of the left atrium, and continuous wave Doppler, especially when a mechanical valve is present.     

Assessment of normal and abnormal prosthetic mitral valves by Doppler echocardiography

Pulsed, continuous-wave, and color Doppler were performed in 165 normal mitral prostheses and 58 patients with prosthetic dysfunction (46 regurgitant and 12 obstructive valves) proved by catheterization and/or surgery. Mean mitral gradient (MG) and pressure half-time (PHT) were determined in all cases. Among normal prostheses, a wide range of both MG and PHT was observed in each type of valve and a considerable overlap between valves of different size. St-Jude's valve had the most optimal hemodynamics. Mild mitral insufficiency was detected in 14% of tissue and 24% of mechanical mitral valves. Repeat studies were performed in 30 patients over a 2.4 years period. Nine patients developed Doppler evidence of new prosthetic dysfunction, while Doppler parameters remained unchanged in 21 patients during the follow-up period. Among malfunctioning valves, Doppler correctly identified all cases of prosthetic obstruction (n=12), and 42 of 46 regurgitant valves. We conclude that Doppler echocardiography is a very useful technique in both non-invasive assessment and follow-up of normal prosthetic valves in the mitral position and in detecting prosthetic dysfunction, especially when prosthetic obstruction is present.     

Evaluation of hypertrophic cardiomyopathy by Doppler color flow imaging: initial observations

We evaluated hypertrophic cardiomyopathy in 12 patients by Doppler color flow imaging and continuous-wave Doppler echocardiography. Mitral regurgitation was detected by continuous-wave Doppler echocardiography in eight patients and was related to the degree of systolic anterior motion of the mitral valve. Adequate color flow images were obtained in 10 of the 12 patients, and mitral regurgitation was demonstrated in 6. A qualitative and quantitative analysis of the color flow imaging revealed a temporal pattern in the left ventricular outflow tract that consisted of normal-velocity laminar flow during early systole followed by turbulent flow in midsystole. The maximal amount of mitral regurgitation on color flow imaging occurred late in systole, after the appearance of turbulent flow in the left ventricular outflow tract. Of the 12 patients, 10 had late-peaking continuous-wave Doppler velocity profiles in the left ventricular outflow tract. The peak velocity detected in the left ventricular outflow tract was positively correlated with the degree of systolic anterior motion of the mitral valve. Patients with higher peak velocities in the left ventricular outflow tract had prolonged ejection times. These findings on Doppler echocardiography support the concept of left ventricular outflow obstruction in some patients with hypertrophic cardiomyopathy.     

Color Doppler sonographic findings in renal vascular lesions

Three patients with renal vascular lesions, one congenital arteriovenous (AV) fistula and two renal pseudoaneurysms, were assessed with color Doppler sonography. The AV fistula was detected initially by color Doppler after having been missed by both real-time sonography and computed tomography. High frequency shift blood flow within a hypoechoic lesion noted by color Doppler characterized the AV communication. Both renal pseudoaneurysms had detectable bidirectional swirling blood flow within an anechoic portion of a complex mass. Findings in all three cases were confirmed by angiography or pathology. Color Doppler sonography seems potentially useful in the evaluation of renal vascular pathology.     

肺静脉血流频谱评价冠心病患者左心室舒张功能的价值

目的：应用彩色多普勒超声心动图研究冠心病患者肺静脉血流频谱对左心室舒张功能的价值。方法：用彩色多普勒超声心动图检测冠心病患者和相同年龄组正常人各45例的右上肺静脉血流频谱峰值（Sp、Dp、ap）及其速度时间积分（Si、Di、ai），与所检测的二尖瓣口血流频谱峰值（Ep、Ap)、速度时间积分（Ei、Ai)及等容舒张时间相比较，将结果对比分析。结果：冠心病组ap、ai较正常组显著增大，Si、Dp、Di和Dp/ap、Di/ai值明显减小，ap、ai增大幅度与左室舒张功能明显相关。二尖瓣口血流频谱测值一般反映了左室舒张功能状态，但对几例出现的“伪正常”频谱表现难以明确评价。结论：肺静脉血流可直观反映冠心病患者左心房内的压力状态，其频谱特征与二尖瓣口血流频谱结合评价左室舒张功能较用二尖瓣口血流频谱一种方法更加准确可靠。     

Diastolic Mitral Regurgitation in Patients with First-Degree Atrioventricular Block

Diastolic mitral regurgitation has been observed in patients with DDD pacemakers when the atrioventricular (AV) delay was prolonged. However, diastolic mitral regurgitation associated with first-degree AV block has not been fully studied. We examined transmitral blood flow in 24 patients with first-degree AV block and normal cardiac function (ages 35.3 ± 17.4 years), and in nine patients with DDD pacemakers and normal cardiac function (ages 73.1 ± 8.1 years), using pulsed Doppler echocardiography. Diastolic mitral regurgitation was observed in 19 of 24 patients with first-degree AV block. Although PQ interval was shortened from 0.32 ± 0.06 to 0.20 ± 0.05 seconds (P < 0.01) after 1 mg atropine sulfate IV, the interval between P wave (ECG) and the beginning of diastolic mitral regurgitation did not change, while the duration of diastolic mitral regurgitation was shortened from 0.15 ± 0.03 to 0.05 ± 0.03 seconds (P < 0.01). There was a significant correlation between changes in PQ interval and changes in the duration of diastolic mitral regurgifation (r = 0.92, P < 0.001). Although cardiac output (3.9 ± 0.05 L/min) and pulmonary capillary wedge pressure (5.1 ± 1.5 mmHg) were normal in all patients with pacemakers, diastolic mitral regurgitation was observed when the AV delay was prolonged. The critical PQ interval for the appearance of diastolic mitral regurgitation was 0.23 ± 0.01 seconds. In patients with prolonged PQ intervals, delayed ventricular contraction following atrial contraction may be associated with mitral regurgitation in the presence of a reversed AV pressure gradient. The results of this study suggest that diastolic mitral regurgitation occurs not only in patients with DDD pacemakers, but also with AAIR pacemakers when the PQ interval is prolonged. The occurrence of diastolic mitral regurgitation is associated with the pacing mode or the setting of AV delay.     

左室流出道梗阻继发感染性二尖瓣穿孔的超声心动图2例

目的探讨左室流出道梗阻继发感染性二尖瓣前叶穿孔的超声心动图特点。方法选择左室流出道梗阻继发感染性二尖瓣前叶穿孔及单纯左室流出道梗阻病例,采用数字化超声心动图技术,比较2种情况下二尖瓣返流的特点及二尖瓣形态学改变。结果左室流出道梗阻继发感染性二尖瓣前叶穿孔时有下列特点:(1)二尖瓣返流由源于前叶体部及瓣叶对合缘的2束返流构成,在心尖四腔切面上返流束呈“Y”字形;(2)二尖瓣返流连续多普勒频谱为2束返流共同形成的叠加频谱;(3)二尖瓣前叶体部可见结构改变。单纯左室流出道梗阻者无上述特点,其二尖瓣返流为单一起源的偏心返流束。结论左室流出道梗阻继发感染性二尖瓣前叶穿孔时,二尖瓣返流束的起源、形态、频谱及二尖瓣前叶结构均有特征性改变。     

血流会聚法测二尖瓣机械瓣有效面积的价值

本研究通过经食管超声心动图对二尖瓣位机械瓣左房侧血流会聚现象的观察测量，利用血流会聚法对３７例经食管超声检查的二尖瓣换瓣术后患者二尖瓣机械瓣有效面积进行测定，并与压力半降法测定二尖瓣机械瓣有效面积进行比较，结果表明血流会聚法测定的二尖瓣机械瓣有效面积与压力半降法有良好相关（第一等速面ｒ＝０．８７，Ｐ＜０．０５；第二等速面ｒ＝０．７５，ｐ＜０．０５）。作者认为：血流会聚法是一种较有价值的测定二尖瓣机械瓣有效面积的方法。     

Quantifying Mitral Regurgitation: Added Value of Three-Dimensional Echocardiography

Current three-dimensional (3D) echocardiographic technology, including live 3D transesophageal echocardiography and single-beat 3D color Doppler imaging, are providing valuable new insight into the mechanism and quantification of mitral valve dysfunction. In this review we discuss important applications of 3D volumetric leaflet imaging with emphasis on the distinction between organic and functional mitral regurgitation. We also discuss the added benefit of current and emerging 3D color Doppler methods for the quantification of mitral regurgitation severity. The limitations of the 2D proximal isovelocity surface area method are discussed, along with potential solutions provided by 3D color Doppler imaging methods that do not require assumptions about the converging flow geometry. Methods to directly measure the vena contracta area of a regurgitant jet are presented along with recent validation studies comparing this method to a reference standard of cardiac MRI. In brief, we review the established and emerging applications of 3D color Doppler techniques for the quantification of mitral regurgitation severity.     

Observations on Doppler mid-diastolic mitral flow reversal

Mitral regurgitation is detected occasionally in diastole during severe aortic regurgitation, hypertrophic cardiomyopathy and atrioventricular block. We have noticed mitral mid-diastolic flow reversal in both patients and many normal subjects. To evaluate this flow phenomenon, pulsed Doppler mitral flow velocity and M-mode echocardiographic recordings were obtained in 38 normal subjects (age range, 16 to 61 years). Fifteen of 38 subjects (40%) had mid-diastolic flow reversal, defined as reversed flow occurring in mid-diastole with a duration greater than 50 msec. Mid-diastolic flow reversal was more common in subjects with longer RR intervals (1031 versus 893 msec), more rapid M-mode echocardiographic EF (early diastolic deceleration) slopes of mitral valve anterior leaflet motion (141 versus 93 mm/sec), and more rapid deceleration of early diastolic mitral flow velocities (612 versus 426 cm/sec2). Mid-diastolic flow reversal by Doppler color flow mapping was recorded in the left atrium in all subjects, even in subjects without mid-diastolic flow reversal shown by pulsed Doppler echocardiography. However, subjects with mid-diastolic flow reversal detected by pulsed Doppler echocardiography demonstrated greater extension of flow into left atrium (10.4 versus 4.1 mm) and longer duration (112 versus 69 msec) of color flow reversal. These data suggest that mid-diastolic flow reversal represents a physiologic intravalvular flow that is possibly the result of reflected flow from the vigorous early diastolic mitral semiclosure.     

Doppler echocardiographic and electrocardiographic atrioventricular time intervals in newborn infants: evaluation of techniques for surveillance of fetuses at risk for congenital heart block.

OBJECTIVE: To evaluate one novel and two previously reported Doppler flow velocimetric techniques to estimate atrioventricular (AV) time intervals, suggested to be useful for early identification of fetuses at risk for congenital heart block. METHODS: In 22 newborn infants, Doppler tracings were obtained from the mitral valve/aortic outflow and the superior vena cava/ascending aorta, as an ECG was recorded simultaneously. AV time intervals were measured using the onsets of the mitral A-wave/aortic outflow (MV-Ao), superior vena cava a-wave/aortic flow (SVC-Ao), and mitral A-wave/mitral valve closure (MV) as indirect markers of electrical atrial/ventricular activation. RESULTS: Close positive linear relationships to the electrocardiographic PR interval were demonstrated for the MV-Ao (r = 0.82, S(y/x) = 7.4 ms), SVC-Ao (r = 0.85, S(y/x) = 6.8 ms), and MV (r = 0.92, S(y/x) = 3.8 ms) approaches. Both techniques using the aortic flow to indicate ventricular activation overestimated the PR interval: the MV-Ao by + 32 +/- 7.7 ms (mean +/- SD) and the SVC-Ao approach by + 22 +/- 7.0 ms. The new MV approach using mitral closure for the same purpose did not overestimate the PR interval, but there was a trend towards underestimation of the PR intervals as time intervals increased. CONCLUSIONS: When systematic differences between echocardiographic and electrocardiographic AV time intervals are compensated for, all three techniques are useful to get indirect estimates of the PR interval. As MV recordings only need insonation of a single valve, and are thus easier to obtain, this technique may be of value as a first screening method to identify fetuses in need for further surveillance. In cases with AV time prolongation the SVC-Ao method seems superior.     

Anatomic and functional evaluation of pure and associated mitral stenoses using the echo-Doppler scanner technique

Twelve normal subjects, 18 control patients and 25 patients with mitral valve lesions (MVL), including 10 pure stenoses (MS), and 15 associated regurgitations (MS + MR) were investigated using a 2-dimensional (2D) pulse echo Doppler procedure, the latter group before open heart surgery. The Doppler signal output consisted of an audio-signal and of a graphic display including an analogue flow velocity trace and a frequency spectrum (Time Interval Histogram). The investigation was two-fold. (1) Diagnosis and assessment of severity of MVL comparing 2D echo and Doppler reliability. The main criteria for diagnosis relied, firstly for the 2D pulsed echo technique on the determination of the planimetric mitral valve area (MVA) for MS and on the finding of an increased annulus diameter for MR, and secondly for the Doppler technique, on the detection of diastolic (MS) and systolic (MR) anomalies of the mitral flow velocity patterns. (2) 2D echo-cardiographic assessment of the mitral apparatus (valves, annulus, subvalvular apparatus), studied on the basis of quantitative and qualitative data. Independently performed correlations with catheterization, angiographic and surgical data showed that a positive diagnosis of MS was obtained in all cases, both with 2D echo and Doppler techniques with a specificity of 92% for the former and 96% for the latter. The assessment of the severity of lesions was satisfactory in 88% of cases for the Doppler, and in 80% of cases for the 2D echo technique with a linear correlative coefficient at 0.83 for the value of MVA measured at catheterization and echocardiography. For MR, a net advantage in diagnosis was found for the Doppler technique (sensitivity of 93%, specificity of 92%) as compared with the 2D echo technique (sensitivity of 33%, specificity of 82%), and also for the assessment of the severity (60% for 2D echo and 85% for Doppler). Furthermore, Doppler assessment of the site of regurgitation and of the direction of the regurgitant jet was in agreement with all the cases also submitted to invasive investigations. Quantitative data obtained by the 2D echo technique for the assessment of the annulus diameter, and of the quality of mitral valve tissue (pliable, fibrous, calcified) or subvalvular apparatus (discrete, moderate, severe alterations), significantly differentiated normals from patients, but no clear-cut separation appeared for patients between close types of alterations. A better assessment was achieved from qualitative data for mitral valve tissue (76% of cases), and subvalvular apparatus (84% of cases).