Optimization of Microbubble Concentration and Acoustic Pressure for Left Ventricular High-Frame-Rate EchoPIV in Patients.

High-frame-rate (HFR) echo-particle image velocimetry (echoPIV) is a promising tool for measuring intracardiac blood flow dynamics. In this study, we investigate the optimal ultrasound contrast agent (UCA: SonoVue) infusion rate and acoustic output to use for HFR echoPIV (PRF = 4900 Hz) in the left ventricle (LV) of patients. Three infusion rates (0.3, 0.6, and 1.2 ml/min) and five acoustic output amplitudes (by varying transmit voltage: 5, 10, 15, 20, and 30 V-corresponding to mechanical indices of 0.01, 0.02, 0.03, 0.04, and 0.06 at 60-mm depth) were tested in 20 patients admitted for symptoms of heart failure. We assess the accuracy of HFR echoPIV against pulsed-wave Doppler acquisitions obtained for mitral inflow and aortic outflow. In terms of image quality, the 1.2-ml/min infusion rate provided the highest contrast-to-background ratio (CBR) (3-dB improvement over 0.3 ml/min). The highest acoustic output tested resulted in the lowest CBR. Increased acoustic output also resulted in increased microbubble disruption. For the echoPIV results, the 1.2-ml/min infusion rate provided the best vector quality and accuracy; mid-range acoustic outputs (corresponding to 15-20-V transmit voltages) provided the best agreement with the pulsed-wave Doppler. Overall, the highest infusion rate (1.2 ml/min) and mid-range acoustic output amplitudes provided the best image quality and echoPIV results.

Time course and risk factors for myocardial dysfunction after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Myocardial wall motion abnormalities (WMAs) are independent risk factors for a poor outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). OBJECTIVE: To study the time course of WMAs during the initial phase after aSAH and to investigate which clinical, electrocardiographic, or myocardial serum markers are predictors of early or late development of WMAs. METHODS: In a prospective, multicenter cohort study in patients with aSAH, we performed serial electrocardiography and echocardiography and measured troponin T and N-terminal pro-B-type natriuretic peptide. WMAs present on admission were considered early WMAs; those that developed during the clinical course were considered late WMAs. Using multivariable regression analysis, we calculated odds ratios with corresponding 95% confidence intervals for clinical parameters, electrocardiography, and myocardial serum makers with early or late occurrence of WMAs. RESULTS: We included 301 patients (mean age ± SD, 57 ± 13) years. Multivariable odds ratios for early WMAs were poor clinical condition, 2.7 (95% confidence interval: 1.1-6.8); sinus tachycardia, 5.0 (1.3-19.9); ST-segment depression, 3.7 (1.02-13.1); ST-segment elevation, 16.6 (1.5-178.9); and increased troponin T, 2.8 (1.1-7.3). Multivariable odds ratios (95% confidence intervals) for late development of WMAs were 6.8 (1.6-30) for a myocardial infarct pattern on admission electrocardiography and 3.4 (1.4-8.5) for increased troponin T on admission. CONCLUSION: WMAs may be present on admission or develop during the course of aSAH. Poor neurological condition on admission, sinus tachycardia, ST-segment depression, and ST-segment elevation on admission electrocardiography and increased troponin T are independent predictors of early WMAs; a myocardial infarct pattern on admission ECG and increased troponin T independently predict late WMAs. CLINICAL TRIAL REGISTRATION: NCT00123695.

Recovery of long-axis left ventricular function after aortic valve replacement in patients with severe aortic stenosis.

BACKGROUND: Patients with aortic stenosis (AS) should undergo aortic valve replacement (AVR) before irreversible LV dysfunction has developed. Assessment of long-axis left ventricular (LV) function may assist in proper timing of AVR. OBJECTIVES: To assess serial changes in long-axis LV function before and after AVR in patients with severe AS and preserved LV ejection fraction. METHODS: The study comprised 27 consecutive patients (mean age 64.9 ± 11.7 years, 15 males) with symptomatic severe AS, scheduled for AVR. Seventeen subjects without known cardiac disease, matched for age, gender, LV ejection fraction and cardiovascular risk factors, served as a control group. Long-axis LV function assessment was done with tissue Doppler imaging at 3 weeks, 6 months, and 12 months after AVR. RESULTS: Mean aortic valve area in the AS group was 0.70 ± 0.24 cm². Pre-AVR peak systolic mitral annular velocities were significantly lower compared to controls (6.7 ± 1.5 vs. 8.9 ± 2.0 cm/s, P < 0.05). Post-AVR peak systolic mitral annular velocities improved to 9.1 ± 2.9 at 3 weeks, 8.6 ± 2.7 at 6 months, and 8.1 ± 1.7 cm/s at 12 months (P < 0.05). Improvements were seen over the whole range of pre-AVR peak systolic mitral annular velocities. Patients with improved Sm after AVR (defined as ≥ 10% compared to baseline values) did not differ in baseline characteristics as compared to those who did not improve. CONCLUSIONS: In patients with severe AS and preserved LV ejection fraction, abnormal systolic mitral annular velocities improve after AVR, independent of the pre-AVR value.

Alterations in left ventricular untwisting with ageing.

BACKGROUND: In order to gain further insight into age-associated changes of left ventricular (LV) diastolic function, the purpose of the current study was to investigate alterations in LV untwisting with ageing. METHODS AND RESULTS: The study comprised 75 healthy volunteers, classified into 3 groups: age 16-35 (n=25), 36-55 (n=25) and 56-75 (n=25) years. LV untwisting (as a percentage of peak systolic twist) at 5%, 10%, 15% and 50% of diastole, peak diastolic untwisting velocity, time-to-peak diastolic untwisting velocity and untwisting rate (mean untwisting velocity during the time interval from peak systolic twist to mitral valve opening) were assessed using speckle-tracking echocardiography. Untwisting at 5%, 10%, 15% and 50% of diastole decreased with ageing. Although the peak diastolic untwisting velocity and untwisting rate were not significantly different between the age groups, when normalized for LV peak systolic twist, these parameters decreased with advancing age (both P<0.01). Time-to-peak diastolic untwisting velocity increased with ageing (P<0.01). CONCLUSIONS: Impairment of the relative peak diastolic untwisting velocity and untwisting rate, resulting in delayed LV untwisting, may help to explain diastolic dysfunction in the elderly. (Circ J 2010; 74: 101 - 108).

Prognostic role of aortic atherosclerosis and coronary flow reserve in patients with suspected coronary artery disease.

BACKGROUND: The degree of aortic atherosclerosis (AA) and coronary flow reserve (CFR) can be evaluated simultaneously during the same transoesophageal echocardiographic (TEE) examination. The aim of the present study was to assess the relative prognostic value of simultaneously evaluated CFR and AA by TEE in patients with suspected or known coronary artery disease (CAD). METHODS: The present study comprised 397 inhospital patients with chest pain. All patients underwent a transthoracic echocardiographic study to evaluate left ventricular function and a vasodilator TEE study to evaluate simultaneously CFR and the degree of AA. RESULTS: Coronary angiography was performed in 292 patients (74%). Significant CAD was less frequent in patients with normal CFR and low-grade AA. During a mean follow-up of 41+/-12 months, 23 patients suffered cardiovascular death (14 sudden cardiac death, 7 heart failure, 2 cardiovascular thrombosis). Univariate analysis yielded age, diabetes, AA grade and CFR as predictors of survival. Multivariate regression analysis showed that only CFR (hazard ratio (HR) 2.9, P<0.02) and diabetes (HR 3.8, P<0.01) were independent predictors of survival. CONCLUSIONS: It can be said that both CFR and AA grade are associated with poor survival but only CFR is an independent predictor.

Spectral pulsed-wave tissue Doppler imaging lateral-to-septal delay fails to predict clinical or echocardiographic outcome after cardiac resynchronization therapy.

AIMS: The current study sought to assess if pre-implantation lateral-to-septal delay (LSD) > or =60 ms assessed by spectral pulsed-wave myocardial tissue Doppler imaging (PW-TDI) could predict successful long-term outcome after cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Sixty patients (72% males, mean age 59 +/- 10 years) who were referred for CRT according to the ACC/ESC guidelines were enrolled in the study. All patients underwent spectral PW-TDI before and 1 year after CRT. Two left ventricular (LV) dyssynchrony time intervals, T(O) and T(P) (time to onset and peak of LV myocardial velocity, respectively), LSD were recorded. Left ventricular dyssynchrony was defined as LSD > or =60 ms. Clinical response was defined as an improvement in >1 NYHA class plus improvement in 6-min walk distance (6MWD) > or =25%, echocardiographic response was defined as a > or =15% reduction in LV end-systolic volume (LV-ESV). One year after CRT, 50 patients (83%) were clinical responders and 47 patients (78%) were echocardiographic responders. Both T(O) and T(P) LV dyssynchrony indices failed to predict echocardiographic CRT outcome. In addition, there were no significant differences between 'synchronous' and 'dyssynchronous' patient populations at baseline or follow-up in either clinical (NYHA class and 6MWD) or echocardiographic (LV ejection fraction, LV end-diastolic, and end-systolic) variables. CONCLUSION: The great majority of patients referred for CRT benefit clinically from it. However, spectral PW-TDI failed to predict CRT outcome. When PW-TDI dyssynchrony was applied for selection of proper CRT patients, up to 80-86% of the patients with synchronous LSD that had proven clinical and echocardiographic benefit from CRT would have been denied CRT.