Cocaine-induced vasoconstriction in the human coronary microcirculation: new evidence from myocardial contrast echocardiography.

BACKGROUND: Cocaine is a major cause of acute coronary syndrome, especially in young adults; however, the mechanistic underpinning of cocaine-induced acute coronary syndrome remains limited. Previous studies in animals and in patients undergoing cardiac catheterization suggest that cocaine constricts coronary microvessels, yet direct evidence is lacking. METHODS AND RESULTS: We used myocardial contrast echocardiography to test the hypothesis that cocaine causes vasoconstriction in the human coronary microcirculation. Measurements were performed at baseline and after a low, nonintoxicating dose of intranasal cocaine (2 mg/kg) in 10 healthy cocaine-naïve young men (median age, 32 years). Postdestruction time-intensity myocardial contrast echocardiography kinetic data were fit to the equation y=A(1-e(-ßt)) to quantify functional capillary blood volume (A), microvascular flow velocity (ß), and myocardial perfusion (A×ß). Heart rate, mean arterial pressure, and left ventricular work (2-dimensional echocardiography) were measured before and 45 minutes after cocaine. Cocaine increased mean arterial pressure (by 14±2 mm Hg [mean±SE]), heart rate (by 8±3 bpm), and left ventricular work (by 50±18 mm Hg·mL(-1)·bpm(-1)). Despite the increases in these determinants of myocardial oxygen demand, myocardial perfusion decreased by 30% (103.7±9.8 to 75.9±10.8 arbitrary units [AU]/s; P<0.01) mainly as a result of decreased capillary blood volume (133.9±5.1 to 111.7±7.7 AU; P<0.05) with no significant change in microvascular flow velocity (0.8±0.1 to 0.7±0.1 AU). CONCLUSIONS: In healthy cocaine-naïve young adults, a low-dose cocaine challenge evokes a sizeable decrease in myocardial perfusion. Moreover, the predominant effect is to decrease myocardial capillary blood volume rather than microvascular flow velocity, suggesting a specific action of cocaine to constrict terminal feed arteries.

Left atrial size and function are related to pulmonary hypertension in coronary artery disease.

BACKGROUND: Left atrial (LA) size reflects diastolic burden and is a prognostic parameter of common cardiovascular death. However, the association between LA size and function and pulmonary hypertension (PH) in coronary artery disease (CAD) has not been well investigated. We hypothesized that LA size and function are associated with PH in CAD. METHODS: One hundred seven patients with CAD were studied. LA size was determined in three different methods; namely, LA volume index (LAV), LA area index, and LA dimension. LAV total emptying fraction was also determined. Pulsed Doppler E, A, E/A, DT, tissue Doppler E', A', and E/E' were measured. Pulmonary artery systolic pressure (PASP) was estimated. RESULTS: All LA size parameters are significantly associated with PH. LAV emptying fraction, age, E, E/A, E/E', and A' were also associated with PH significantly. CAD patients with PH showed larger LA size, higher E, E/A, and E/E' and lower LAV emptying fraction, A and A' than CAD patients without PH. Multivariate regression analysis revealed that maximum LAV, E, E/A ratio, and age were independent predictors of PH. Maximum LAV > 35.6 mL/m(2) predicted PASP > 40 mmHg with a sensitivity of 83.9% and specificity of 62.2%. CONCLUSION: LAV is associated with PH in CAD patients.

Bachmann Bundle and its arterial supply: imaging with multidetector CT--implications for interatrial conduction abnormalities and arrhythmias.

PURPOSE: To retrospectively investigate anatomy of Bachmann Bundle (BB) and its vascular supply at 64-section multidetector computed tomography (CT) in healthy patients and patients with abnormalities. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study and waived informed consent. Clinical histories, electrocardiograms (ECGs), and coronary 64-section multidetector CT angiograms in 317 patients were reviewed (healthy group, 164; group with abnormalities, 153). Among patients with abnormalities, 68 had atrial fibrillation (AF) or interatrial conduction block (IAB) (P wave duration, >or=120 msec), 46 had severe coronary artery disease (CAD) (>or=70% stenosis of coronary artery giving rise to sinuatrial node [SAN] artery), and 39 had severe CAD and an abnormal ECG (AF or IAB). Length, anteroposterior and superoinferior diameters, attenuation, and vascular supply of BB were studied. Student t test for continuous variables and contingency tables for categorical variables were used. RESULTS: BB was visualized, to greater degree, in the healthy group (90.2% vs 73.9% for group with abnormalities, P < .001). Visualization of BB was similar among subgroups with abnormalities: 71.7% in patients with severe CAD, 73.5% in patients with abnormal ECG, and 76.9% in patients with severe CAD and abnormal ECG. BB measurements were similar for both groups. Patients with nonvisualized BB displayed lower overall mean attenuation in the region, with -30.6 HU +/- 33.4 (standard deviation), but mean attenuation in healthy patients was 51.3 HU +/- 59.9 (P < .001). This finding suggests fatty infiltration. BB and BB region were mainly supplied by the right SAN artery (55.5%), followed by the left SAN artery (39.6%) and both SAN arteries (4.9%). In the group with abnormalities, there was a significant difference for SAN artery nonvisualization between those with and without identifiable BB (P = .001). CONCLUSION: BB and its vascular supply can easily be demarcated on cardiac CT images. BB was visualized less in patients with severe CAD and abnormal ECG, a finding that suggests that disease of BB fibers may play a role in development of atrial arrhythmias.

Imaging of patent foramen ovale with 64-section multidetector CT.

PURPOSE: To investigate the feasibility of 64-section multidetector computed tomography (CT) by using CT angiography (a) to demonstrate anatomic detail of the interatrial septum pertinent to the patent foramen ovale (PFO), and (b) to visually detect left-to-right PFO shunts and compare these findings in patients who also underwent transesophageal echocardiography (TEE). MATERIALS AND METHODS: In this institutional review board-approved HIPAA-compliant study, electrocardiographically gated coronary CT angiograms in 264 patients (159 men, 105 women; mean age, 60 years) were reviewed for PFO morphologic features. The length and diameter of the opening of the PFO tunnel, presence of atrial septal aneurysm (ASA), and PFO shunts were evaluated. A left-to-right shunt was assigned a grade according to length of contrast agent jet (grade 1, 1 cm to 2 cm; grade 3, >2 cm). In addition, 23 patients who underwent both modalities were compared (Student t test and linear regression analysis). A difference with P < .05 was significant. RESULTS: A flap valve, seen in 101 (38.3%) patients, was patent at the entry into the right atrium (PFO) in 62 patients (61.4% of patients with flap valve, 23.5% of total patients). A left-to-right shunt was detected in 44 (16.7% of total) patients (grade 1, 61.4%; grade 2, 34.1%; grade 3, 4.5%). No shunt was seen in patients without a flap valve. Mean length of PFO tunnel was 7.1 mm in 44 patients with a shunt and 12.1 mm in 57 patients with a flap valve without a shunt (P < .0001). In patients with a tunnel length of 6 mm or shorter, 92.6% of the shunts were seen. ASA was seen in 11 (4.2%) patients; of these patients, a shunt was seen in seven (63.6%). In 23 patients who underwent CT angiography and TEE, both modalities showed a PFO shunt in seven. CONCLUSION: Multidetector CT provides detailed anatomic information about size, morphologic features, and shunt grade of the PFO. Shorter tunnel length and septal aneurysms are frequently associated with left-to-right shunts in patients with PFO.

Right atrial cavotricuspid isthmus: anatomic characterization with multi-detector row CT.

PURPOSE: To retrospectively evaluate the anatomic characteristics of the right atrial cavotricuspid isthmus (CTI) by using 64-section multi-detector row computed tomography (CT). MATERIALS AND METHODS: Institutional review board approval and waiver of informed consent were obtained for this HIPAA-compliant study. The anatomic region of the CTI was evaluated in 201 patients (116 men and 85 women; mean age, 58 years +/- 11 [standard deviation]) who underwent coronary multi-detector row CT. CTI length was assessed along three parallel isthmic levels (paraseptal, central, and inferolateral). Central isthmus depth was classified as straight (3 mm), concave (>3 to 5 mm). Measurements were obtained during three cardiac phases: midsystole, middiastole, and atrial contraction. Subthebesian recess dimensions and eustachian ridge width were measured. Distances from the atrioventricular node artery to the coronary sinus, from the right coronary artery (RCA) to the inferior vena cava, and from the RCA to the tricuspid valve annulus were measured. Software was used for statistical analysis. RESULTS: At middiastole, the paraseptal isthmus (mean length, 20 mm +/- 3.5; range, 11-34 mm) was significantly shorter than the central isthmus (24 mm +/- 4.3; range, 12-43 mm) and the central isthmus was shorter than the inferolateral isthmus (27 mm +/- 4.8; range, 13-45 mm) (P < .001). The longest CTI measurements were obtained during midsystole, and the shortest were obtained during atrial contraction (40% variation per cardiac cycle). Isthmus contraction occurred primarily in the posterior segment of the central isthmus (RCA to inferior vena cava distance). At middiastole, the central isthmus was straight in 8% of patients, concave in 47% of patients, and pouchlike (>5 mm) in 45% of patients. The mean depth was greater during atrial contraction (6.3 mm +/- 2.1) than in midsystole (4.3 mm +/- 1.5) and middiastole (5.1 mm +/- 1.8) (32% variation during cardiac cycle). A subthebesian recess greater than 5 mm deep was identified in 45% of patients. In 24% of patients, a thick eustachian ridge greater than 4 mm was seen. The atrioventricular node artery passed close to the coronary sinus wall (mean distance, 2.1 mm +/- 0.7; range, 1-6 mm). CONCLUSION: Cardiac multi-detector row CT provides extensive information regarding the size and morphology of the CTI and its related structures.

Arterial supply to sinuatrial and atrioventricular nodes: imaging with multidetector CT.

PURPOSE: To retrospectively evaluate the depiction of anatomic characteristics of the arterial supply to the sinuatrial node (SAN) and the atrioventricular node (AVN) with 64-section computed tomography (CT). MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study; informed consent was not required. Anatomic origin, number, course, and variants of the arteries to the SAN and AVN were examined with coronary multidetector CT in 102 patients (55 men, 47 women; mean age, 57 years +/- 13 [standard deviation]). Known accessory blood supplies to the AVN, including left and right Kugel anastomotic arteries, were investigated. Possible extension of the first septal perforating artery to the AVN was evaluated. Univariate and bivariate statistical data were reported. Means +/- standard deviations, 95% confidence intervals, and percentages were calculated. RESULTS: A single sinuatrial nodal artery originated from the proximal 40 mm of the right coronary artery (RCA) in 67 and from the proximal 35 mm of the left circumflex (LCX) artery in 28 patients. A dual blood supply to the SAN was seen in six patients. The sinuatrial nodal artery was not visualized in one patient. An S-shaped variant was seen in 18% of left sinuatrial nodal arteries and invariably traveled posteriorly in the sulcus between the left superior pulmonary vein and left atrial appendage. The sinuatrial nodal artery approached the nodal tissue by one of three routes-retrocaval (47.5%), precaval (42.6%), or pericaval (9.9%). The AVN was supplied by the RCA in 89 patients, the LCX artery in 11 patients, and by both arteries in two patients. Two left and six right Kugel anastomotic arteries were detected as supplying the AVN area. The first septal perforating artery had no detectable connection to the AVN. CONCLUSION: The arterial blood supply to the SAN and the AVN is variable and can be imaged with multidectector CT. SUPPLEMENTAL MATERIAL: http://radiology.rsnajnls.org/cgi/content/full/2461070030/DC1.

MDCT of the S-shaped sinoatrial node artery.

OBJECTIVE: The purpose of this study was to use 64-MDCT to investigate the anatomic characteristics of the S-shaped variant of the sinoatrial node (SAN) artery and to describe the clinical implications of the findings in ablative procedures involving the left atrium. MATERIALS AND METHODS: Coronary CT angiograms of 250 patients (152 men, 98 women; mean age, 60 +/- 12 [SD] years) were retrospectively analyzed for identification of the origin, number, anatomic course, mode of termination, and S-shaped variant of the SAN artery. RESULTS: At least one SAN artery was detected in 244 patients. The S-shaped variant was seen in 35 (14.3%) of these patients. Thirty-four of the variants (30.6% of all left SAN arteries) arose from the proximal to middle portion of the left circumflex artery (mean distance between the ostium of the left circumflex artery and the origin of S-shaped variant, 28.7 +/- 13.1 mm). The other variant (0.7% of all right SAN arteries) originated from the distal right coronary artery. The S-shaped variant was the only artery supplying the SAN in 28 (11.4%) of the patients. In patients with two arteries supplying the SAN, the right SAN artery and the S-shaped variant of the left SAN artery were seen together in seven patients. The S-shaped SAN artery (mean distance from atrial wall, 2.43 +/- 0.992 mm) had a predictable proximal course, lying in the posterior aspect in a groove between the orifices of the left superior pulmonary vein and the left atrial appendage close to the left atrial wall. The terminal segment of the artery approached the nodal tissue posterior to the superior vena cava in 22 patients, anterior to the vena cava in 10 patients, and through branches surrounding the vena cava in two patients. CONCLUSION: The S-shaped variation of the SAN artery is common and has a characteristic anatomic course. MDCT can be used to plan surgical and catheter-based left atrial interventions in which this artery is at risk of injury.

Comparison between MDCT and Grayscale IVUS in a Quantitative Analysis of Coronary Lumen in Segments with or without Atherosclerotic Plaques.

BACKGROUND: The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. OBJECTIVES: We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. METHODS: The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. RESULTS: At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. CONCLUSIONS: In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques.

Usefulness of compensatory hyperkinesis in the noninfarcted left ventricular wall in separating single from multivessel coronary artery disease in patients with initial ST-elevation acute myocardial infarction.

We assessed the contractility of the contralateral wall on 2-dimensional echocardiography in 50 patients with an initial ST-elevation acute myocardial infarction who underwent coronary angiography. Compensatory hyperkinesis, which we defined as a fractional thickening of >/=60% in the contralateral wall, was a strong predictor of single-vessel coronary artery disease, with a positive predictive value of 85%.

Impact of pulmonary hypertension on outcomes in patients with functional mitral regurgitation undergoing percutaneous edge-to-edge repair.

Preexisting pulmonary hypertension (PH) is associated with poor outcomes after surgical mitral valve repair for functional mitral regurgitation (FMR). However its clinical impact on MitraClip therapy remains unknown. The aim of this study was therefore to evaluate the impact of preexisting PH on MitraClip therapy for patients with FMR. Ninety-one consecutive patients who had FMR and who underwent the MitraClip procedure were studied. They were divided into 2 groups on the basis of pulmonary artery systolic pressure: the PH group (n = 48) and the non-PH group (n = 43). PH was defined as pulmonary artery systolic pressure >50 mm Hg using Doppler echocardiography. Procedural success (defined as magnetic resonance reduction to grade 2+ or less) and 30-day mortality were similar in the 2 groups. At 12 months, New York Heart Association functional class had improved to class I or II in most patients in the PH (from 2.9% to 94.3%) and non-PH (from 9.4% to 96.9%) groups. The mean pulmonary artery systolic pressure of the PH group significantly decreased from baseline but remained higher than that of the non-PH group (50.8 ± 15.3 vs 36.7 ± 11.6 mm Hg, p <0.001). After a mean of 25.0 ± 16.9 months of follow-up, Kaplan-Meier analysis demonstrated significantly higher all-cause mortality in the PH group. In Cox regression analysis, preexisting PH was the most powerful predictor of all-cause mortality (hazard ratio 3.731, 95% confidence interval 1.653 to 8.475, p = 0.002). In conclusion, MitraClip therapy reduced FMR and alleviated symptoms with an excellent early safety profile in the PH and non-PH groups. However, preexisting PH was associated with worse all-cause mortality.

Evaluation of vegetation size and its relationship with embolism in infective endocarditis: a real-time 3-dimensional transesophageal echocardiography study.

BACKGROUND: Two-dimensional (2D) echocardiography studies have shown that the maximum length of vegetation (MLV)≥10 mm is a predictor of embolic events (EEs) in patients with infective endocarditis. However, 2D measurements probably underestimate the vegetation dimensions. In this study, we evaluated the feasibility of real-time 3-dimensional transesophageal echocardiography (RT3DTEE) in determining MLV and its accuracy in identifying the risk for EEs compared with 2D transesophageal echocardiography (2DTEE). METHODS AND RESULTS: We analyzed 60 patients with vegetations. RT3DTEE measurement of MLV was obtained with Advanced QLAB Quantification Software by cropping the 3D volume with the appropriate 2D plane to obtain the largest value. The standard 2DTEE images were also evaluated to determine the MLV. Major EEs were registered from medical records, and a logistic regression analysis was performed to determine the association between MLV and EEs. The RT3DTEE MLV was larger than the 2DTEE value with a mean difference of 3.2 mm (95% confidence interval, 2.1-4.2 mm). The best cut-off value for prediction of EEs was MLV≥20 mm with RT3DTEE and MLV≥16 mm with 2DTEE. The positive predictive value increased from 59.1% to 65.2% when RT3DTEE was used. The accuracy of classification of patients with EEs increased from 65% to 70% with this new technique. CONCLUSIONS: RT3DTEE is a feasible technique for the analysis of vegetation morphology and size that may overcome the shortcoming of 2DTEE, leading to a better prediction of the embolism risk in patients with infective endocarditis.

Effect of transcatheter aortic valve replacement on the mitral valve apparatus and mitral regurgitation: real-time three-dimensional transesophageal echocardiography study.

BACKGROUND: The effect of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing the reduction of mitral regurgitation with or without mitral leaflet tethering after TAVR are poorly understood. The present 3-dimensional (3D) transesophageal echocardiography study aimed to elucidate early changes further in the structure and function of the mitral valve apparatus after TAVR. METHODS AND RESULTS: We analyzed 90 patients (nontenting group, 56 patients and tenting group, 34 patients) who underwent TAVR using the Edwards SAPIEN and had intraprocedural 3D transesophageal echocardiography evaluation of the mitral valve. Of all patients, mitral regurgitation improved in 54%, remained the same in 38%, and worsened in 8% 1 day after TAVR. There were no statistically significant differences in mitral annular 3D parameters before and after TAVR in both groups. In the tenting group, tenting area (P<0.01) and tenting height (P<0.01) were decreased, and coaptation length was increased (P<0.05) after TAVR. In a multivariable analysis, the predictors of improved mitral regurgitation were the decrease of tenting area (odds ratio, 8.15; 95% confidence interval, 1.31-50.7; P<0.05) and the decrease of valvuloarterial impedance (odds ratio, 7.57; 95% confidence interval, 1.15-49.9; P<0.05) in the tenting group and the decrease of valvuloarterial impedance (odds ratio, 6.96; 95% confidence interval, 1.24-39.2; P<0.05) in the nontenting group. CONCLUSIONS: Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in mitral regurgitation after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.

Comparison of two-dimensional versus real-time three-dimensional transesophageal echocardiography for evaluation of patent foramen ovale morphology.

The aim of this study was to elucidate patent foramen ovale (PFO) morphology and the change of PFO size using real-time 3-dimensional (3D) transesophageal echocardiography (TEE). PFO is a 3D structure, and its shape changes during the cardiac cycle. Therefore, it may be difficult to estimate accurate PFO morphology using 2-dimensional (2D) TEE. The study included 50 patients with PFO who underwent 2D and 3D TEE. PFO heights (PHs) at entrance, mid, and exit were measured by 2D and 3D TEE. Systolic and diastolic areas were also measured by 3D TEE. PH by 3D TEE was larger than that by 2D TEE (entrance 0.32 ± 0.18 vs 0.21 ± 0.15 cm, p <0.001; mid 0.25 ± 0.14 vs 0.15 ± 0.11 cm, p <0.001; exit 0.19 ± 0.11 vs 0.11 ± 0.08 cm, p <0.001). Systolic area was greater than diastolic area at each location (entrance 0.19 ± 0.17 vs 0.11 ± 0.11 cm(2), p = 0.001; mid 0.13 ± 0.11 vs 0.08 ± 0.06 cm(2), p = 0.001; exit 0.09 ± 0.09 vs 0.06 ± 0.05 cm(2), p = 0.01). Additionally, entrance area was greater than exit area in systole and diastole (systole 0.19 ± 0.17 vs 0.09 ± 0.09 cm(2), p <0.001; diastole 0.11 ± 0.11 vs 0.06 ± 0.05 cm(2), p = 0.001). There were good correlations between PH by 3D TEE and PFO area (entrance r = 0.68, mid r = 0.71, exit r = 0.78) but weak correlations between PH by 2D TEE and PFO area (entrance r = 0.62, mid r = 0.50, exit r = 0.51). In conclusion, real-time 3D TEE could provide detailed and unique information on PFO morphology.

Comparison of real-time three-dimensional transesophageal echocardiography to two-dimensional transesophageal echocardiography for quantification of mitral valve prolapse in patients with severe mitral regurgitation.

Real-time 3-dimensional (3D) transesophageal echocardiography (TEE) provides more accurate geometric information on the mitral valve (MV) than 2-dimensional (2D) TEE. The aim of this study was to quantify MV prolapse using real-time 3D TEE in patients with severe mitral regurgitation. In 102 patients with severe mitral regurgitation due to MV prolapse and/or flail, 2D TEE quantified MV prolapse, including prolapse gap and width in the commissural view. Three-dimensional TEE also determined prolapse gap and width with the use of the 3D en face view. On the basis of the locations of MV prolapse, all patients were classified into group 1 (pure middle leaflet prolapse, n = 50) or group 2 (involvement of medial and/or lateral prolapse, n = 52). Prolapse gap and prolapse width determined by 3D TEE were significantly greater than those by 2D TEE (all p values <0.001). The differences in prolapse gap and prolapse width between 2D TEE and 3D TEE were significantly greater in group 2 than group 1 (Δ gap 1.3 ± 1.4 vs 2.4 ± 1.8 mm, Δ width 2.5 ± 3.0 vs 4.4 ± 5.1 mm, all p values <0.01). The differences in prolapse gap and width between 2D TEE and 3D TEE were best correlated with 3D TEE-derived prolapse width (r = 0.41 and r = 0.74, respectively). Two-dimensional TEE underestimated the width of MV prolapse and leaflet gap compared to 3D TEE. Two-dimensional TEE could not detect the largest prolapse gap and width, because of the complicated anatomy of the MV. In conclusion, 3D TEE provided more precise quantification of MV prolapse than 2D TEE.

Aortic annular sizing for transcatheter aortic valve replacement using cross-sectional 3-dimensional transesophageal echocardiography.

OBJECTIVES: This study compared cross-sectional three-dimensional (3D) transesophageal echocardiography (TEE) to two-dimensional (2D) TEE as methods for predicting aortic regurgitation after transcatheter aortic valve replacement (TAVR). BACKGROUND: Data have shown that TAVR sizing using cross-sectional contrast computed tomography (CT) parameters is superior to 2D-TEE for the prediction of paravalvular aortic regurgitation (AR). Three-dimensional TEE can offer cross-sectional assessment of the aortic annulus but its role for TAVR sizing has been poorly elucidated. METHODS: All patients had severe symptomatic aortic stenosis and were treated with balloon-expandable TAVR in a single center. Patients studied had both 2D-TEE and 3D imaging (contrast CT and/or 3D-TEE) of the aortic annulus at baseline. Receiver-operating characteristic curves were generated for each measurement parameter using post-TAVR paravalvular AR moderate or greater as the state variable. RESULTS: For the 256 patients studied, paravalvular AR moderate or greater occurred in 26 of 256 (10.2%) of patients. Prospectively recorded 2D-TEE measurements had a low discriminatory value (area under the curve = 0.52, 95% confidence interval: 0.40 to 0.63, p = 0.75). Average cross-sectional diameter by CT offered a high degree of discrimination (area under the curve = 0.82, 95% confidence interval: 0.73 to 0.90, p < 0.0001) and mean cross-sectional diameter by 3D-TEE was of intermediate value (area under the curve = 0.68, 95% confidence interval: 0.54 to 0.81, p = 0.036). CONCLUSIONS: Cross-sectional 3D echocardiographic sizing of the aortic annulus dimension offers discrimination of post-TAVR paravalvular AR that is significantly superior to that of 2D-TEE. Cross-sectional data should be sought from 3D-TEE if good CT data are unavailable for TAVR sizing.

Comparison of left ventricular outflow geometry and aortic valve area in patients with aortic stenosis by 2-dimensional versus 3-dimensional echocardiography.

The present study sought to elucidate the geometry of the left ventricular outflow tract (LVOT) in patients with aortic stenosis and its effect on the accuracy of the continuity equation-based aortic valve area (AVA) estimation. Real-time 3-dimensional transesophageal echocardiography (RT3D-TEE) provides high-resolution images of LVOT in patients with aortic stenosis. Thus, AVA is derived reliably with the continuity equation. Forty patients with aortic stenosis who underwent 2-dimensional transthoracic echocardiography (2D-TTE), 2-dimensional transesophageal echocardiography (2D-TEE), and RT3D-TEE were studied. In 2D-TTE and 2D-TEE, the LVOT areas were calculated as π × (LVOT dimension/2)(2). In RT3D-TEE, the LVOT areas and ellipticity ([diameter of the anteroposterior axis]/[diameter of the medial-lateral axis]) were evaluated by planimetry. The AVA is then determined using planimetry and the continuity equation method. LVOT shape was found to be elliptical (ellipticity of 0.80 ± 0.08). Accordingly, the LVOT areas measured by 2D-TTE (median 3.7 cm(2), interquartile range 3.1 to 4.1) and 2D-TEE (median 3.7 cm(2), interquartile range 3.1 to 4.0) were smaller than those by 3D-TEE (median 4.6 cm(2), interquartile range 3.9 to 5.3; p <0.05 vs both 2D-TTE and 2D-TEE). RT3D-TEE yielded a larger continuity equation-based AVA (median 1.0 cm(2), interquartile range 0.79 to 1.3, p <0.05 vs both 2D-TTE and 2D-TEE) than 2D-TTE (median 0.77 cm(2), interquartile range 0.64 to 0.94) and 2D-TEE (median 0.76 cm(2), interquartile range 0.62 to 0.95). Additionally, the continuity equation-based AVA by RT3D-TEE was consistent with the planimetry method. In conclusion, RT3D-TEE might allow more accurate evaluation of the elliptical LVOT geometry and continuity equation-based AVA in patients with aortic stenosis than 2D-TTE and 2D-TEE.

Atropine as an adjunct to supine bicycle stress echocardiography: an alternative strategy to achieve target heart rate or rate pressure product.

AIMS: To investigate the use of atropine to achieve target heart rate (THR) and rate pressure product (RPP) during supine bicycle exercise stress echocardiography (SBESE) to increase the number of diagnostic stress tests. METHODS AND RESULTS: Forty-four patients that were unable to achieve THR or RPP during SBESE performed to evaluate ischaemia were given 0.4-1.2 mg of atropine to augment THR and RPP. After atropine (0.7 ± 0.3 mg) the maximum heart rate (HR) achieved was 133 (± 16) bpm, mean THR was 82% (± 8%), and average RPP was 22 716 (± 4915) b/min × mmHg. Of the patients with a non-diagnostic SBESE, with the use of atropine 80% of those patients achieved a diagnostic test. There were no major adverse affects from the administration of atropine. CONCLUSION: The use of atropine to augment the HR or RPP during SBESE (i) is safe; (ii) enables the assessment of ischaemia at peak effort; and (iii) allows assessment of exercise haemodynamics in patients with sub-maximal exercise capacity and chronotropic incompetence.

Non-circular shape of right ventricular outflow tract: a real-time 3-dimensional transesophageal echocardiography study.

BACKGROUND: The shape of right ventricular outflow tract (RVOT) has been assumed to be circular. The aim of this study was to assess RVOT morphology using 3-dimensional transesophageal echocardiography (3D TEE). METHODS AND RESULTS: This prospective study included 114 patients who underwent 3D TEE. Two-dimensional (2D) TEE measured maximum and minimum RVOT diameters (RVOTD max and min) during a cardiac cycle. 3D TEE determined RVOT area (RVOTA) max and min, RVOT fractional area change, and RVOT shape index (RVOTSI; vertical/horizontal RVOTD). Cardiac output (CO) was calculated using 2D TEE, 3D TEE, and a Swan-Ganz catheter in 23 patients. All patients were classified into group 1 (RVOTSI ≤1) or group 2 (RVOTSI >1) based on the RVOT shapes. The mean RVOTSIs were 0.84±0.21(max) and 0.82±0.20 (min). Only 17 patients (14.9%) had circular RVOT (RVOTSI: 0.95-1.05); 82 patients (71.9%) were categorized into group 1 and 32 patients (28.1%) into group 2. 2D TEE, compared with 3D TEE, underestimated RVOTA max and min (both P<0.001). CO with 3D TEE had better agreement with CO with a catheter than CO with 2D TEE (r=0.83 and 0.53, respectively). CONCLUSIONS: 3D TEE revealed that RVOT geometry was not generally circular but oval with 2 different types. Because of the detailed morphological information of RVOT, 3D TEE could provide more accurate assessment of CO than 2D TEE.

Echocardiographic evaluation of iatrogenic atrial septal defect after catheter-based mitral valve clip insertion.

The geometries and sizes of persistent iatrogenic atrial septal defects (IASDs) after transseptal puncture during catheter-based mitral valve clip insertion (MVCI) have not been detailed. In this study, 11 IASDs were investigated in 10 patients who underwent MVCI using a guide catheter (24Fr proximally and 22Fr at the atrial septum). The diameters of the long and short axes and the area at maximum and minimum during a cardiac cycle were measured after MVCI using real-time 3-dimensional (RT3D) transesophageal echocardiography (TEE). A circular shape was assumed on 2-dimensional TEE, resulting in an area calculation of π × (dimension/2)(2). The anatomic geometries of IASDs were visualized in a 3-dimensional en face view of the atrial septum. Furthermore, 1 month after MVCI, IASDs were evaluated using echocardiography. The IASDs had a variety of irregular geometries. The mean long-axis diameter was 1.0 ± 0.24 cm, the mean short-axis diameter was 0.51 ± 0.22 cm, and the mean area was 0.40 ± 0.24 cm(2) on RT3D TEE. The diameters and area changed significantly between the maximal and minimal values during the cardiac cycle. Importantly, 2-dimensional TEE underestimated the maximal diameters of IASDs (0.54 ± 0.17 vs 1.0 ± 0.24 cm by RT3D TEE, p <0.01) and the maximal areas of IASDs (0.25 ± 0.15 vs 0.40 ± 0.23 cm(2) by RT3D TEE, p <0.05). One month after MVCI, the smallest and the second smallest IASDs had closed, and the other 9 remained open. In conclusion, RT3D TEE is useful to assess the irregular geometries of IASDs created during MVCI.

Tadalafil alleviates muscle ischemia in patients with Becker muscular dystrophy.

Becker muscular dystrophy (BMD) is a progressive X-linked muscle wasting disease for which there is no treatment. Like Duchenne muscular dystrophy (DMD), BMD is caused by mutations in the gene encoding dystrophin, a structural cytoskeletal protein that also targets other proteins to the muscle sarcolemma. Among these is neuronal nitric oxide synthase (nNOSµ), which requires certain spectrin-like repeats in dystrophin's rod domain and the adaptor protein α-syntrophin to be targeted to the sarcolemma. When healthy skeletal muscle is subjected to exercise, sarcolemmal nNOSµ-derived NO attenuates local α-adrenergic vasoconstriction, thereby optimizing perfusion of muscle. We found previously that this protective mechanism is defective-causing functional muscle ischemia-in dystrophin-deficient muscles of the mdx mouse (a model of DMD) and of children with DMD, in whom nNOSµ is mislocalized to the cytosol instead of the sarcolemma. We report that this protective mechanism also is defective in men with BMD in whom the most common dystrophin mutations disrupt sarcolemmal targeting of nNOSµ. In these men, the vasoconstrictor response, measured as a decrease in muscle oxygenation, to reflex sympathetic activation is not appropriately attenuated during exercise of the dystrophic muscles. In a randomized placebo-controlled crossover trial, we show that functional muscle ischemia is alleviated and normal blood flow regulation is fully restored in the muscles of men with BMD by boosting NO-cGMP (guanosine 3',5'-monophosphate) signaling with a single dose of the drug tadalafil, a phosphodiesterase 5A inhibitor. These results further support an essential role for sarcolemmal nNOSµ in the normal modulation of sympathetic vasoconstriction in exercising human skeletal muscle and implicate the NO-cGMP pathway as a putative new target for treating BMD.