Pulsed-wave Doppler Imaging Research Articles

Atrial Electromechanical Interval Can Identify Patients With Paroxysmal Atrial Fibrillation and is Associated With CHADS2 Score and Peak Velocity of Left Atrial Appendage

It is difficult to discriminate patients with and without paroxysmal atrial fibrillation (PAF). The atrial electromechanical interval determined by the transthoracic echocardiogram is demonstrated to be a predictor of new onset AF. The aim of our study was to investigate whether the electromechanical interval is a useful parameter to identify patients with PAF. A total of 297 patients (PAF group = 103; control group = 194) with mean age of 59.4 ± 12.4 years were enrolled. The electromechanical interval (PA-PDI) defined as the time interval from the initiation of the P-wave deflection to the peak of the mitral inflow A wave on the pulse-wave Doppler imaging was measured for every patient. Patients with PAF had significantly longer PA-PDI intervals compared with that of patients without it (152.7 ± 13.8 ms vs 133.4 ± 16.8 ms). The area under ROC curve based on the PA-PDI interval to diagnose PAF was 0.803 (95% confidence interval = 0.755-0.851, P < 0.001). At the cut-off value of 142 ms, the sensitivity and specificity in identifying PAF were 77.7% and 80.1%, respectively. In the PAF group, the PA-PDI interval was closely associated with the CHADS(2) score and inversely related with the peak velocity of left atrial appendage. The PA-PDI interval may be a useful parameter to identify patients with PAF. Further studies are necessary to evaluate the usefulness of PA-PDI intervals in diagnosing PAF in addition to the current methods and tools.

Characterization of fetal cardiac structure and function detected by echocardiography in women with normal pregnancy and gestational diabetes mellitus

To assess fetal cardiac structure and function in normal pregnancy and in the presence of gestational diabetes mellitus (GDM) using echocardiography measurements. We studied fetal cardiac structure and function in 169 uncomplicated singleton pregnancies and in 92 complicated by GDM. Maternal glycemic control was deemed adequate in 75 women and inadequate in 17. Fetal two-dimensional ultrasound, pulsed wave Doppler and tissue Doppler imaging (TDI) were used to assess cardiac walls thickness and cardiac function, both systolic [with ejection fraction (EF)] and diastolic [using early diastolic peak flow velocity (E)/late peak of diastolic velocity (A) and early diastolic peak velocity at the annulus (Ea)/late diastolic peak velocity at the annulus (Aa) ratios]. In normal pregnancies, fetal ventricular walls and interventricular septum thickness increased progressively with advancing gestation and were significantly thicker in the presence of GDM (P < 0.001) independently of maternal glycemic control. Fetal cardiac systolic function indicated by EF did not change during normal pregnancy, but was significantly increased (P < 0.001) in the presence of GDM independently of maternal glycemic control. Both pulsed wave Doppler and TDI indicators of fetal diastolic cardiac function increased during normal pregnancy, reaching a maximum at 36 to 40 weeks of gestation (P < 0.001). The presence of GDM did not affect pulsed wave Doppler indicators of diastolic function [ratio of early/late diastolic peak flow velocity (E/A ratio)], whereas TDI indices [ratio of early/late diastolic peak velocity at the annulus (Ea/Aa ratio)] were significantly lower after adjustment for gestational age and estimated fetal weight (EFW); and such changes were independent of maternal diabetic control (P < 0.001). Fetal cardiac wall thickness, cardiac systolic and diastolic functions are affected by GDM independently of glycemic control.

Conventional and segmental myocardial Tei indices measurement in patients with acute ST-segment elevation myocardial infarction: Is there a relation?

Background: Myocardial infarction (MI) results in impairment of left ventricular (LV) systolic and diastolic functions to various degrees. The tissue Doppler image derived Tei index (TDI-Tei index) has recently been used to assess LV function, and like the conventional Tei index, it was also found to be useful for global function. There are a small number of studies which apply TDI-Tei index to assess regional function and whether it varies according to the degree of changes in wall motion in various LV segments. Objectives: This study was conducted to assess the changes of segmental myocardial Tei index by TDI according to the degree of changes of wall motion in the patient with acute ST-segment elevation myocardial infarction (STEMI) and its correlation with Tei index derived by conventional Doppler. Patients and methods: This study was carried out on thirty patients with acute STEMI selected from Coronary Care Unit, Cardiology Department, Mansoura Specialized Hospital, Mansoura University, Egypt. The study group was subjected to clinical assessment, electrocardiography (ECG), routine laboratory profile and Doppler echocardiography (conventional and pulsed wave tissue Doppler imaging “PW-TDI”). Tei index was calculated from the sum of isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT), divided by ejection time (ET) which were measured from pulsed wave Doppler imaging of the trans-mitral inflow and LV outflow tracts. Myocardial velocities and TDI-Tei index were measured at basal and mid-segments of LV walts from apical 4, 2 and 5-chamber views using 16-segment model. Average values of myocardial velocities and TDI-Tei indices were obtained from normal, hypokinetic and akinetic segments then compared. Results: The mean values of left ventricular ejection fraction (LVEF), mitral E/A ratio and conventional Tei index were 51.83 ± 5.15%, 1.18 ± 0.15 and 0.63 ± 0.07 ms, respectively. Segmental myocardial TDI-Tei index was correlated positively with conventional Tei index ( r = 0.648, P < 0.001). TDI-Tei indices were significantly higher in akinetic and hypokinetic segments than those of normal segments (0.70 ± 0.09, 0.64 ± 0.05 vs 0.63 ± 0.05, P < 0.001). Conclusions: Tei index (either conventional or TDI) is superior to EF in evaluation of LV performance in patients with acute STEMI. Tei index derived by myocardial segments by TDI is correlated with conventional Tei index. Segmental TDI-Tei index values differ according to the grade of dysfunctional wall motion.

Prolonged Atrium Electromechanical Interval Was Associated with Strokes in Patients with Atrial Fibrillation after Successful Catheter Ablation

Background: Atrial fibrillation (AF) was associated with increased risk of strokes. Catheter ablation of AF provides an effective therapy for patients with drug-refractory AF. The aim of this study was to evaluate whether the atrial electromechanical interval was useful in identifying patients at risks of strokes after successful catheter ablations. Methods: Total 295 AF patients who received catheter ablations without recurrences were enrolled. Electromechanical interval (PA-PDI) was determined as the time interval from the initiation of P wave deflection to the peak of mitral inflow A wave on the pulse wave Doppler imaging. The PA-PDI interval was measured 3 months after the catheter ablation. The clinical endpoint was the occurrence of ischemic stroke. Results: During the mean follow up of 46.5 months, 6 patients suffered from ischemic strokes. Patients with strokes had higher CHADS2 scores and longer PA-PDI intervals. In the multivariate analysis, the PA-PDI interval was an independent predictor of strokes with the hazard ratio of 1.131 per one mm increment. At a cut-point of 150 ms identified by the ROC curve, the positive and negative predictive values of the PA-PDI interval to predict strokes were 86.7% and 100%, respectively Conclusions: The PA-PDI interval was a useful tool to identify patients with high risks of strokes after successful catheter ablations of AF.

Associations between the atrial electromechanical interval, atrial remodelling and outcome of catheter ablation in paroxysmal atrial fibrillation

ObjectiveThe atrial electromechanical (PA–PDI) interval was reported to be a useful predictor of new-onset atrial fibrillation (AF) and the occurrence of AF after coronary artery bypass surgery. The aim of...

2-D high-frame-rate dynamic elastography using delay compensated and angularly compounded motion vectors: Preliminary results

This paper describes a new ultrasound-based system for high-frame-rate measurement of periodic motion in 2-D for tissue elasticity imaging. Similarly to conventional 2-D flow vector imaging, the system acquires the RF signals from the region of interest at multiple steering angles. A custom sector subdivision technique is used to increase the temporal resolution while keeping the total acquisition time within the range suitable for real-time applications. Within each sector, 1-D motion is estimated along the beam direction. The intra- and inter-sector delays are compensated using our recently introduced delay compensation algorithm. In-plane 2-D motion vectors are then reconstructed from these delay-compensated 1-D motions. We show that Young's modulus images can be reconstructed from these 2-D motion vectors using local inversion algorithms. The performance of the system is validated quantitatively using a commercial flow phantom and a commercial elasticity phantom. At the frame rate of 1667 Hz, the estimated flow velocities with the system are in agreement with the velocity measured with a pulsed-wave Doppler imaging mode of a commercial ultrasound machine with manual angle correction. At the frame rate of 1250 Hz, phantom Young's moduli of 29, 6, and 54 kPa for the background, the soft inclusion, and the hard inclusion, are estimated to be 30, 11, and 53 kPa, respectively.

E0694 Evaluation of left heart function in patients with type 2 diabetes mellitus by Doppler echocardiography

ObjectiveTo assess left ventricular (LV) structure, LV function, left atrial (LA) structure and LA systolic function by using all the currently available echocardiographic methods in patients with type 2 diabetes...

Comparison of Pulsed Wave and Color Doppler Myocardial Velocity Imaging in Healthy Dogs

Tissue velocity imaging (TVI) is increasingly used in small animal cardiology. Tissue velocity of the myocardial wall can be measured by pulsed wave (PW) or color Doppler (CD) imaging methods. Currently, the same reference ranges are used for PW TVI and CD TVI methods. However, if and how both methods correlate, and whether they can be used interchangeably, have not been assessed in small animals. To compare the results of PW TVI and CD TVI measurements. Seventy-one healthy dogs. Longitudinal myocardial velocity profiles were recorded from the 4-chamber left apical view. Peak maximal systolic (S), early (E), and late diastolic (A) velocities were measured off-line in a blinded fashion in the septal and lateral left ventricular wall by PW TVI and CD TVI. Differences between peak PW TVI and CD TVI waves were analyzed by a paired t-test. Regression analysis and Bland-Altman difference plots also were used to assess agreement between methods. There was a significant correlation between PW TVI and CD TVI (P < .001). However, S, E, and A waves measured by PW TVI were significantly higher than the CD TVI values (P < .001). Peak systolic and diastolic PW velocities were approximately 2.20 cm/s higher than corresponding mean CD TVI velocities. PW TVI measurements are significantly higher compared with CD TVI measurements. Theses differences are clinically relevant. These methods should not be used interchangeably, and different reference ranges for PW TVI and CD TVI should be used.

Evaluation of left ventricular dyssynchrony using combined pulsed wave and tissue Doppler imaging.

IntroductionThe combination of pulsed wave (PW) and tissue Doppler imaging (TDI) has been proposed as a new method to assess left ventricular (LV) mechanical dyssynchrony (LVMD), but results have not been validated. We investigated the correlation of a combination of PW and TDI with a positive response to cardiac resynchronization therapy (CRT).Material and methodsWe studied 108 consecutive patients who received CRT. Patients with atrial fibrillation were excluded. The time difference (TPW-TDI) between onset of QRS to the end of LV ejection by PW (TPW) and onset of QRS to the end of the systolic wave in LV basal segments with greatest delay by TDI (TTDI) was measured before CRT and during short-term and long-term follow-up.ResultsThe TPW-TDI interval before CRT was 74 ±48 ms. Intra-observer variabilities for TPW and TTDI were 1.5 ±0.24% and 1 ±0.17%. Inter-observer variabilities for TPW and TTDI were 1 ±0.36% and 1 ±0.64%, respectively. TPW-TDI > 50 ms was defined as the cutoff value for diagnosis of LVMD by receiver operating curve (ROC) analysis. During follow-up of 15 ±11 months, the sensitivity and specificity of TPPW-TDI to predict a positive response to CRT were 98% and 82%, respectively. The area under the ROC curve was 0.92. There was a significant agreement between LVMD determined by TPW-TDI and the positive response to CRT (κ=0.80).ConclusionsLeft vertricular dyssynchrony detected by the method combining PW and TDI demonstrated a high reproducibility, sensitivity, specificity and agreement with a positive response to CRT.

Effects of levosimendan versus dobutamine on left atrial function in decompensated heart failure

Although the effects of levosimendan on the left ventricle (LV) have been studied, its effect on left atrial (LA) function is poorly understood, despite its key role in optimizing LV function. To compare the effects of levosimendan and dobutamine on LA and LV function in patients with decompensated heart failure (DHF). Seventy-four patients (mean [+/- SD] age 64+/-10 years) with DHF and an LV ejection fraction of 35% or lower were randomly assigned to receive levosimendan (n=37) or dobutamine (n=37). LA active emptying fraction, LA passive emptying fraction (PEF) and the ratio of mitral inflow early diastolic velocity to annulus velocity (E/e) were evaluated with pulsed wave and tissue Doppler imaging along with plasma B-type natriuretic peptide (BNP) level measurements before and after drug infusion. The ejection fraction was significantly increased in both groups. The levosimendan group had a greater decrease in BNP and a greater increase in active emptying fraction at 24 h compared with the dobutamine group. The PEF, E/e and deceleration time of the E wave were significantly improved in the levosimendan group, but not in the dobutamine group. Levosimendan- induced percentage change of BNP was significantly correlated with the percentage change of E/e and PEF (r=0.48 [P<0.005] and r=-0.38 [P<0.05], respectively). In patients with DHF, levosimendan and dobutamine both improve LV systolic function. However, levosimendan also improves LV diastolic function and LA performance in parallel with a greater improvement in neurohormonal activation compared with dobutamine.

Bidirectional Flow Within the Intratesticular Arteries Caused by Microvenous Thrombosis Secondary to Testicular Torsion

The human testicular microvasculature is unique among mammals with its intricate network of venous anastomoses and adjacent venules, essential for maintaining adequate blood circulation to support rapidly dividing germ cells. Interruption of the blood supply, such as seen in testicular torsion, causes cellular injury with the potential for diminished endocrine function as well as reduced spermatogenesis. 1 Torsion-induced ischemia can result in 50% organ loss if surgical detorsion is delayed for more than 12 hours and 90% organ loss if surgery is performed after 24 hours. 2 Testicular torsion is more commonly seen in patients younger than 25 years and is frequently associated with anatomic variations of the processus vaginalis, particularly the bell clapper abnormality. 3,4 The condition is rarer in the older patient and may be associated with age-related lengthening of the spermatic cord, giving greater flexibility for rotation along the axis of the cord. In the absence of trauma, particularly in the older patient, the presenting features mimic epididymo-orchitis, a strangulated hernia, and torsion of the appendix testis. 4 Inaccuracy in the clinical diagnosis mandates adjunctive diagnostic methods, typically sonography and radionuclide scintigraphy. Because of its availability, sonography is often the imaging modality of choice, with the finding of reduction or absence of blood flow within the intratesticular vasculature as shown by color Doppler imaging correlating favorably with surgically proven testicular torsion (88.9% sensitivity and 90% specificity 5 ). The use of pulsed wave Doppler imaging has been found to be of limited value in the diagnosis of torsion, in which reduced or absent end-diastolic flow has been documented. 6 A previously reported phenomenon was reversal of frequencies on a Doppler spectral analysis of the intratesticular arteries in a case of torsion. 7 However, this has also been reported in the setting of advanced epididymo-orchitis in which the reason for the finding has been postulated as thrombosis but to our knowledge has previously not been histologically proven. 8 .

Agreement between echocardiographic techniques in assessment of the left ventricular myocardial performance index in rabbits

OBJECTIVE-To report reference values and examine the agreement in the myocardial performance (Tei) index of the left ventricle (LVTI) as measured by tissue Doppler imaging (TDI), pulsed-wave Doppler imaging (PWD), and M-mode echocardiography in clinically normal rabbits. ANIMALS-26 clinically normal male New Zealand White rabbits. PROCEDURES-Echocardiographic examinations that included TDI, PWD, and M-mode echocardiography were performed. Rabbits were sedated by SC administration of ketamine and midazolam. Intraclass correlation coefficients (ICCs) were used to measure absolute agreement among the 3 echocardiographic techniques. Intraclass correlation coefficients were computed for values a and b and for the equation (a - b)/b used to determine LVTI; value a equals the sum of isovolumic contraction time, ejection time, and isovolumic relaxation time, and value b equals the left ventricular ejection time. Values of ICC > 0.75 indicated good agreement between 2 echocardiographic techniques. RESULTS-For value a, Pearson correlation coefficients between pairs of techniques were all high (r r 0.7). However, only the septal TDI and the lateral wall TDI had good agreement (ICC, 0.86). For value b, correlations were generally low with the exception of the correlation between the septal and the lateral wall TDI. For value b, TDI was the only technique with good agreement (ICC, 0.77). For LVTI, only TDI techniques had a significantly positive correlation. All the other correlations were close to zero with a paradoxic moderate negative correlation between PWD-determined LVTI and lateral wall TDI-determined LVTI. CONCLUSIONS AND CLINICAL RELEVANCE-For LVTI, the absolute agreement was poor between all pairs of techniques.

Influence of left ventricular diastolic function on pulmonary function in healthy individuals

The aim of this study was to determine if left ventricular (LV) diastolic function influences pulmonary function (PF) in healthy subjects and to determine if they are independently related after accounting for age, gender, BMI and blood pressure (BP). Echocardiograms and PF tests were performed in 103 healthy subjects (22‐76 yr). The ratio of peak early (E) and late (A) mitral inflow velocities and the ratio of peak early (E') and late (A') mitral annular velocities were obtained by pulsed wave Doppler and tissue Doppler imaging. The first stage of diastolic dysfunction, often observed in healthy aging, is characterized by reduced E and E', and greater A and A' resulting in a reversal of E/A and E'/A'. PF measures included forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO) and forced mid‐expiratory flow (FEF25‐75). Age, gender and BMI accounted for &gt;60% of the interindividual variation between diastolic function and PF. After accounting for age, gender, BMI and BP, E' was positively associated with FVC (additional R2=0.03, P&lt;0.01). A was negatively and A' positively associated with DLCO (additional R2=0.03, R2=0.01, P&lt;0.05) and FVC (additional R2=0.03, R2=0.03, P&lt;0.01). E/A was positively associated with DLCO (additional R2=0.02, P&lt;0.01). In conclusion, LV diastolic function may influence PF in healthy subjects, with the greatest interactions being observed in older males. NIH HL71478

Routine assessment of coeliac axis and renal artery flow is not feasible with transoesophageal echocardiography

Orihashi et al. [1] have previously demonstrated that renal artery flow can be measured with transoesophageal echocardiography. The ability to measure changes in flow in the renal and splanchnic vascular beds would be very advantageous in unstable patients in the operating room or intensive care unit. A major potential limitation to this technique, is that the position of the stomach overlying the abdominal aorta may be sufficiently variable to preclude adequate imaging in many patients. The aim of this audit was to determine how often adequate imaging can be obtained, and the relationship between change in Doppler velocity time integral and cardiac output, in patients undergoing cardiac surgery. The Royal Melbourne Hospital ethics committee approved the study as audit. In 27 patients who had received transoesophageal echocardiography as part of their intra-operative management for cardiac surgery, imaging of the coeliac axis and renal arteries was attempted using an Omniplane II transoesophageal transducer and a SONOS 5500 echocardiography machine (Philips, Medical Systems, Andover, MA, USA). The probe was rotated posterior to overly the abdominal aorta, and retroflexed to identify the coeliac axis and renal arteries. Pulse wave Doppler imaging was performed using angle correction, and the spectral display recorded (Fig. 5a). Imaging was performed prior to cardiopulmonary bypass, and post cardiopulmonary bypass. The velocity time integral was measured as the average of three consecutive cardiac cycles. Cardiac output was measured by thermodilution technique using a pulmonary artery catheter (Baxter Healthcarer Corporation, Irvine, CA, USA) and was the average of three measurements. (a) Transoesophageal images of coeliac (A) and right renal (B) arteries. Color flow Doppler is shown in the coeliac artery (C), and an example of pulse wave Doppler spectral display is shown in (D), illustrating measurement of the velocity–time integral (VTI), used to calculate flow (VTI × cross-sectional area × heart rate) in the vessels. (b) Relationship between cardiac output (CO) and the coeliac and right renal arterial flow, obtained from pulsed wave Doppler spectral images using angle correction. Pre CPB, and Post CPB referred to measurements performed prior to, and following cardiopulmonary bypass. Mean values and standard error of the mean displayed. Of 27 patients, acceptable imaging was not obtained of any vessels in five patients (19%). Acceptable imaging was obtained for the coeliac axis in 22 patients (81%), the right renal artery in 15 patients (56%); and the left renal artery in four patients (15%). The relationship between cardiac output and coeliac or right renal artery flow is shown in Fig. 5b. The flow values are much higher than expected due to use of angle correction and near perpendicular insonation angle. Although there is reasonable correlation pre- and postcardiopulmonary bypass, the values obtained may be useful only to track changes in artery flow, rather than quantifying the actual flow. There were no complications related to the study. Imaging of the coeliac axis was obtainable in the majority of patients, and may be a useful indicator of splanchnic flow, though further study is required to validate the relationship between Doppler derived flow and gut perfusion. Imaging of the renal arteries was difficult, particularly for the left renal artery, and was not obtainable in the majority of patients; thereby limiting its utility is a monitoring tool. Angle correction for pulse wave Doppler was used, however the vessels emerge from the aorta almost perpendicular to the axis of ultrasound imaging, thereby increasing potential error if Doppler is to be used as a quantitative tool.

An Unusual Case of Postoperative Hypoxemia Diagnosed with Transesophageal Echocardiography

An Unusual Case of Postoperative Hypoxemia Diagnosed with Transesophageal Echocardiography

Ectopic Pregnancy Complicated by an Arteriovenous Malformation of the Fallopian Tube

Ectopic pregnancy is still correlated with a high incidence of morbidity and mortality. 1 Increasing occurrences of sexually transmitted diseases (gonorrhea and chlamydia), pelvic inflammatory diseases, previous abortions, bitubal ligations, intrauterine devices, assisted reproductive techniques, late primiparity, and previous surgery are associated with chronic salpingitis, which is the most common finding associated with and responsible for ectopic pregnancy. 2 Improvements in the resolution of high-frequency transvaginal sonography have contributed greatly to the diagnosis of ectopic pregnancy, which has already been correlated with the β-human chorionic gonadotropin (β-hCG) level. 3,4 The introduction of 2-dimensional (2D) transvaginal scanning, color Doppler imaging, and nowadays, 3-dimensional (3D) transvaginal sonography can provide information about the location and size of the ectopic mass and impairment of the tube. Evaluation of these factors is important for selecting the best treatment for the patient and choosing among the different therapeutic possibilities (laparoscopy, methotrexate administration, and expectant management). Arteriovenous malformations (AVMs) in the female genital tract are relatively uncommon lesions in which there is direct communication between arterioles and venules. They can be either congenital or acquired. The association between ectopic pregnancy and AVMs is extremely rare; indeed, in the literature we found just 2 cases of ectopic pregnancy associated with an AVM. 5,6 We report a case of an ectopic pregnancy complicated by an AVM in which 2D transvaginal sonography, color Doppler imaging, pulsed wave Doppler imaging, and new 3D modes, including tomographic ultrasound imaging, the glass body mode, and 3D bidirectional power Doppler (HD-Flow) imaging, indicated the diagnosis and the best surgical plan.

SU‐GG‐J‐196: Vascular Occlusion by Acoustically Vaporized Droplets for Potential Targeted Enhancement of Thermal Therapies

Purpose: Acoustic droplet vaporization (ADV) of perfluorocarbon droplets with boiling points below ambient temperature shows promise for spatially and temporally targeted vascular occlusion. Vascular occlusion of a tumor or other target tissue can decrease the local heat dissipation relative to adjacent normal tissues during less directed or slow thermal therapies, such as RF or ultrasonic ablation. Also, encapsulated drugs can be released with the occluding bubbles into the target tissues. Method and Materials: In six canines, in vivo gray scale imaging and color flow and pulse wave (PW) Doppler imaging were employed with low concentration droplet injections to identify exteriorized target arteries or tissues, avoiding major adjacent veins. Short tone bursts at 3.5 MHz with 0.25% duty cycle were used during bolus passage to vaporize droplets with concentrations comparable to clinical ultrasound contrast agent recommendations. Studies included multiple intracardiac (IC) and intravenous (IV) injections, the latter with lipid, rather than albumin, shell. Results: Bubble production by ADV in arteries or tissues is easily visible in gray scale images. Both IC and IV injections repeatedly produced ADV at will in the renal or segmental artery, each injection and ADV generating vascular occlusion as seen by gray scale and Doppler imaging. Mean cortex occlusion was ∼85% by colored microspheres in the targeted kidney or renal pole with an ∼10 min half life per droplet dose. Cardiopulmonary symptoms occurred in some IC injections. ADV was successful in a canine prostate using an intercavitary imaging array for ADV and targeting. Conclusion: Keys to the new, consistent success with both IC and IV injections include adequate concentrations of droplets, use of frequencies with ADV threshold well below those for cavitation, and reliable targeting. Conflict of Interest: This work was supported in part by NIH RO1EB00281.

The challenge of fetal dysrhythmias: echocardiographic diagnosis and clinical management

The present study aimed to evaluate the management of fetal cardiac dysrhythmias based on prior identification of the underlying electrophysiological mechanism. We studied 36 consecutive fetuses with cardiac dysrhythmia. Rhythm diagnosis was based on M-mode, pulsed wave Doppler and tissue Doppler imaging (TDI). Only fetuses with: (i) incessant tachycardia (> 12 h) and mean ventricular rate > 200 beats/min, (ii) signs of left ventricular dysfunction, or (iii) hydrops, were treated using oral maternal drug therapy. The mean gestational age at diagnosis was 24.3 +/- 4.5 weeks. Twenty-one fetuses had tachycardia with a 1: 1 atrial-ventricular (AV) conduction. Based on ventricular-atrial interval, prenatal diagnosis was: permanent junctional reciprocating (n = 6), atrial ectopic (n = 6) or atrial-ventricular re-entry tachycardia (n = 9). One had atrial flutter, one ventricular tachycardia and four congenital AV block. Nine showed premature atrial or ventricular beats. Fifteen fetuses with incessant tachycardia, left ventricular dysfunction or hydrops were prenatally treated with maternal administration of digoxin, sotalol or flecainide. The total success rate (sinus rhythm or rate control) was 14/15 (93%). Seven fetuses were hydropics. Three of these died (one at 28 weeks of gestation, two in the first week of life). The prenatal diagnosis of dysrhythmia was confirmed at the birth in 31 of 35 live-born. No misdiagnosis was made using TDI. At 3 +/- 1.1-year follow-up, 33/35 children were alive and well. Fetal echocardiography could clarify the electrophysiological mechanism of fetal cardiac dysrhythmias and guide the therapy.

A NOVEL METHOD TO DETECT LEFT VENTRICULAR DYSSYNCHRONY BY PULSED AND TISSUE DOPPLER: SENSITIVITY AND AGREEMENT

PURPOSE: QRS complex width is not an accurate marker of left ventricular mechanical dyssynchrony (LVMD). Echocardiography is the optimal tool to assess LVMD, but results are inconsistent. LVMD determined by a method using combined pulsed wave Doppler (PW) and tissue Doppler imaging (TDI) is a novel method and has been recently reported. Our aims were to evaluate the sensitivity, specificity, positive and negative predictive value and agreement with positive response of cardiac resynchronization therapy (CRT) by using this method.

Handheld vs. Conventional Transesophageal Echocardiography in Non-Cardiac Surgical Intensive Care Unit Patients

We examined the feasibility of a newly developed handheld ultrasound device capable of transesophageal echocardiography (TEE). Prospective case series in a non-cardiac surgical intensive care unit including 18 deeply sedated and endotracheally intubated critically ill non-cardiac surgical patients. The imaging quality and findings of a newly developed handheld device were compared to those of a cart-based standard TEE system. All patients were examined with both systems in a randomized order by independent examiners performing a structured and complete TEE examination. The imaging quality of the standard cardiac cross sections and spectral Doppler studies of the cardiac valves was assessed on an analog scale from 1 (excellent) to 5 (insufficient). The time requirements for each study were documented. We did not detect significant differences in two-dimensional imaging. Continuous-wave Doppler imaging of the left ventricular outflow tract and pulsed-wave Doppler imaging of the transmitral flow were significantly better (p <0.001) with the standard system. Handheld TEE is a goal-oriented diagnostic tool, which may sufficiently replace a standard cart-based TEE system in unstable critically ill patients when an acute gross diagnosis is required.