Right ventricular mechanics and contractility after aortic valve replacement surgery: a randomised study comparing minimally invasive versus conventional approach.

Objective: Minimally invasive aortic valve replacementsurgery (MIAVR) is an alternative surgical technique to conventional aortic valve replacement surgery (AVR) in selected patients. The randomised study Cardiac Function after Minimally Invasive Aortic Valve Implantation (CMILE) showed that right ventricular (RV) longitudinal function was reduced after both MIAVR and AVR, but the reduction was more pronounced following AVR. However, postoperative global RV function was equally impaired in both groups. The purpose of this study was to explore alterations in RV mechanics and contractility following MIAVR as compared with AVR. Methods: A predefined post hoc analysis of CMILE consisting of 40 patients with severe aortic valve stenosis who were eligible for isolated surgical aortic valve replacement were randomised to MIAVR or AVR. RV function was assessed by echocardiography prior to surgery and 40 days post-surgery. Results: Comparing preoperative to postoperative values, RV longitudinal strain rate was preserved following MIAVR (-1.5±0.5 vs -1.5±0.4 1/s, p=0.84) but declined following AVR (-1.7±0.3 vs -1.4±0.3 1/s, p<0.01). RV longitudinal strain reduced following AVR (-27.4±2.9% vs -18.8%±4.7%, p<0.001) and MIAVR (-26.5±5.3% vs -20.7%±4.5%, p<0.01). Peak systolic velocity of the lateral tricuspid annulus reduced by 36.6% in the AVR group (9.3±2.1 vs 5.9±1.5 cm/s, p<0.01) and 18.8% in the MIAVR group (10.1±2.9 vs 8.2±1.4 cm/s, p<0.01) when comparing preoperative values with postoperative values. Conclusions: RV contractility was preserved following MIAVR but was deteriorated following AVR. RV longitudinal function reduced substantially following AVR. A decline in RV longitudinal function was also observed following MIAVR, however, to a much lesser extent.

Improved right ventricular index of myocardial performance in the assessment of right ventricular function after coronary artery bypass grafting.

OBJECTIVES: Decreased right ventricular (RV) longitudinal function following coronary artery bypass grafting (CABG), as assessed by tricuspid annular systolic excursion (TAPSE) and RV peak systolic velocity (RVS') is a known condition. We aimed to explore the feasibility of the right ventricular index of myocardial performance (RIMP) in the assessment of RV function after CABG at rest and during peak dobutamine stress echocardiography (DSE). METHODS: Forty-two patients indicated for CABG were included in this study. Coronary angiography, DSE and exercise bicycle test were performed within 6 weeks before and 3 months after CABG. The RIMP, RVS' and TAPSE at the lateral tricuspid annulus were also assessed. The results were presented as mean ± standard deviation. RESULTS: The RIMP improved after CABG both at rest (0.45 ± 0.11 before vs 0.38 ± 0.08 after CABG, P = 0.013) and during DSE (0.75 ± 0.23 vs 0.49 ± 0.14, P < 0.001). TAPSE declined significantly when comparing the values from before CABG to after CABG both at rest (23.9 ± 4.46 vs 14.6 ± 3.67, P < 0.001) and during DSE (20.9 ± 4.16 vs 11.9 ± 3.60, P < 0.001). RVS' also decreased after CABG both at rest (11.9 ± 2.40 vs 8.5 ± 1.93, P < 0.001) and during DSE (15.6 ± 4.30 vs 10.5 ± 3.21, P < 0.001). On the other hand, exercise capacity improved after CABG compared with baseline (128.4 ± 40.12 W vs 142.1 ± 46.73 W, P = 0.014). CONCLUSIONS: RIMP improved after CABG both at rest and during DSE. The reduction in TAPSE and RVS' after CABG indicate reduced regional mechanical RV function along the long axis rather than reduced global RV function.

Musculoskeletal pain and limitations in work ability in Swedish marines: a cross-sectional survey of prevalence and associated factors.

OBJECTIVES: To estimate the prevalence of self-rated musculoskeletal pain and pain limiting work ability in Swedish Armed Forces (SAF) marines, and to study factors potentially associated with pain limiting work ability for the most prevalent pain regions reported. DESIGN: Population-based, cross-sectional survey. PARTICIPANTS: There were 272 SAF marines from the main marine battalion in Sweden included in the study. OUTCOMES: Self-assessed musculoskeletal pain and pain limiting the marines' work ability within a 6-month period, as obtained from structured questionnaires. The association of individual, health and work-related factors with musculoskeletal pain limiting work ability was systematically regressed with multiple logistic models, estimating OR and 95% CI. RESULTS: Musculoskeletal pain and pain limiting work ability were most common in the back, at 46% and 20%, and lower extremities at 51% and 29%, respectively. Physical training ≤1 day/week (OR 5.3, 95% CI 1.7 to 16.8); body height ≤1.80 m (OR 5.0, 95% CI 1.6 to 15.1) and ≥1.86 m (OR 4.4, 95% CI 1.4 to 14.1); computer work 1/4 of the working day (OR 3.2, 95% CI 1.0 to 10.0) and ≥1/2 (OR 3.3, 95% CI 1.1 to 10.1) of the working day were independently associated with back pain limiting work ability. None of the studied variables emerged significantly associated with such pain for the lower extremities. CONCLUSIONS: Our findings show that musculoskeletal pain and resultant limitations in work ability are common in SAF marines. Low frequency of physical training emerged independently associated with back pain limiting work ability. This suggests that marines performing physical training 1 day per week or less are suitable candidates for further medical evaluation and secondary preventive actions. While also associated, body height and computer work need further exploration as underlying mechanisms for back pain limiting work ability. Further prospective studies are necessary to clarify the direction of causality.

Unique pumping-out fracturing mechanism of a polymer-shelled contrast agent: an acoustic characterization and optical visualization.

This work describes the fracturing mechanism of air-filled microbubbles (MBs) encapsulated by a cross-linked poly(vinyl alcohol) (PVA) shell. The radial oscillation and fracturing events following the ultrasound exposure were visualized with an ultrahigh-speed camera, and backscattered timedomain signals were acquired with the acoustic setup specific for harmonic detection. No evidence of gas emerging from defects in the shell with the arrival of the first insonation burst was found. In optical recordings, more than one shell defect was noted, and the gas core was drained without any sign of air extrusion when several consecutive bursts of 1 MPa amplitude were applied. In acoustic tests, the backscattered peak-to-peak voltage gradually reached its maximum and exponentially decreased when the PVA-based MB suspension was exposed to approximately 20 consecutive bursts arriving at pulse repetition frequencies of 100 and 500 Hz. Taking into account that the PVA shell is porous and possibly contains large air pockets between the cross-linked PVA chains, the aforementioned acoustic behavior might be attributed to pumping gas from these pockets in combination with gas release from the core through shell defects. We refer to this fracturing mechanism as pumping-out behavior, and this behavior could have potential use for the local delivery of therapeutic gases, such as nitric oxide.

Ultrasound speckle tracking for radial, longitudinal and circumferential strain estimation of the carotid artery--an in vitro validation via sonomicrometry using clinical and high-frequency ultrasound.

Ultrasound speckle tracking for carotid strain assessment has in the past decade gained interest in studies of arterial stiffness and cardiovascular diseases. The aim of this study was to validate and directly contrast carotid strain assessment by speckle tracking applied on clinical and high-frequency ultrasound images in vitro. Four polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties and connected to a pump generating carotid flow profiles. Gray-scale ultrasound long- and short-axis images of the phantoms were obtained using a standard clinical ultrasound system, Vivid 7 (GE Healthcare, Horten, Norway) and a high-frequency ultrasound system, Vevo 2100 (FUJIFILM, VisualSonics, Toronto, Canada) with linear-array transducers (12L/MS250). Radial, longitudinal and circumferential strains were estimated using an in-house speckle tracking algorithm and compared with reference strain acquired by sonomicrometry. Overall, the estimated strain corresponded well with the reference strain. The correlation between estimated peak strain in clinical ultrasound images and reference strain was 0.91 (p<0.001) for radial strain, 0.73 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain and for high-frequency ultrasound images 0.95 (p<0.001) for radial strain, 0.93 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain. A significant larger bias and root mean square error was found for circumferential strain estimation on clinical ultrasound images compared to high frequency ultrasound images, but no significant difference in bias and root mean square error was found for radial and longitudinal strain when comparing estimation on clinical and high-frequency ultrasound images. The agreement between sonomicrometry and speckle tracking demonstrates that carotid strain assessment by ultrasound speckle tracking is feasible.

Assessment of the viscoelastic and oscillation properties of a nano-engineered multimodality contrast agent.

Combinations of microbubbles (MBs) and superparamagnetic iron oxide nanoparticles (SPIONs) are used to fabricate dual contrast agents for ultrasound and MRI. This study examines the viscoelastic and oscillation characteristics of two MB types that are manufactured with SPIONs and either anchored chemically on the surface (MBs-chem) or physically embedded (MBs-phys) into a polymer shell. A linearized Church model was employed to simultaneously fit attenuation coefficients and phase velocity spectra that were acquired experimentally. The model predicted lower viscoelastic modulus values, undamped resonance frequencies and total damping ratios for MBs-chem. MBs-chem had a resonance frequency of approximately 13 MHz and a damping ratio of approximately 0.9; thus, MBs-chem can potentially be used as a conventional ultrasound contrast agent with the combined functionality of MRI detection. In contrast, MBs-phys had a resonance frequency and damping of 28 MHz and 1.2, respectively, and requires further modification of clinically available contrast pulse sequences to be visualized.

Endocardial border delineation capability of a novel multimodal polymer-shelled contrast agent.

BACKGROUND: A novel polymer-shelled contrast agent (CA) with multimodal and target-specific potential was developed recently. To determine its ultrasonic diagnostic features, we evaluated the endocardial border delineation as visualized in a porcine model and the concomitant effect on physiological variables. METHODS: Three doses of the novel polymer-shelled CA (1.5 ml, 3 ml, and 5 ml [5 × 10(8) microbubbles (MBs)/ml]) and the commercially available CA SonoVue (1.5 ml [2-5 × 10(8) MBs/ml]) were used. Visual evaluations of ultrasound images of the left ventricle were independently performed by three observers who graded each segment in a 6-segment model as either 0 = not visible, 1 = weakly visible, or 2 = visible. Moreover, the duration of clinically useful contrast enhancement and the left ventricular opacification were determined. During anesthesia, oxygen saturation, heart rate, and arterial pressure were sampled every minute and the effect of injection of CA on these physiological variables was evaluated. RESULTS: The highest dose of the polymer-shelled CA gave results comparable to SonoVue. Thus, no significant difference in the overall segment score distribution (2-47-95 vs. 1-39-104), time for clinically sufficient contrast enhancement (20-40 s for both) and left ventricular overall opacification was found. In contrast, when comparing the endocardial border delineation capacity for different regions SonoVue showed significantly higher segment scores for base and mid, except for the mid region when injecting 1.5 ml of the polymer-shelled CA. Neither high nor low doses of the polymer-shelled CA significantly affected the investigated physiological variables. CONCLUSIONS: This study demonstrated that the novel polymer-shelled CA can be used in contrast-enhanced diagnostic imaging without influence on major physiological variables.

The early diastolic myocardial velocity: a marker of increased risk in patients with coronary heart disease.

OBJECTIVE: Tissue Doppler imaging (TDI) is a promising echocardiographic modality allowing quantification of myocardial performance. However, the prognostic potential of TDI in patients with acute myocardial infarction (AMI) is not yet investigated. We sought to explore the ability of TDI in identifying patients at risk for new cardiovascular events after AMI. METHODS: One hundred and nineteen patients with AMI were recruited prospectively (mean age 61 years; range 32-81 years of age). Patients with diabetes mellitus (DM) were excluded. Echocardiography was performed 3-12 months after AMI. Two-dimensional (2-D) and TDI variables were recorded. The patients were followed during a mean period of 4·6 years (range 1-8 years). The primary end-point was defined as any of the following: death from any cause, non-fatal reinfarction or stroke, unstable angina pectoris, congestive heart failure requiring hospitalization and coronary revascularization procedure. RESULTS: Thirty patients had some form of cardiovascular events during follow-up. Seven patients had cardiovascular death, 13 patients had reinfarction and four patients had a stroke. New angina or unstable angina was recorded in 21 patients. Of these patients, 13 underwent percutaneous coronary angioplasty (PCI) or coronary artery bypass grafting (CABG). The early diastolic myocardial velocity (E(m)) emerged as the only echocardiographic variable that offered a clear differentiation between patients that presented with new cardiovascular (CV) events as compared to the corresponding group without any CV events at follow-up (P<0·05). In multivariate statistical analysis and after adjustment for age, sex, total cholesterol, body mass index (BMI) and other baseline characteristics, Em remained as independent predictors of CV events (HR, 1·18, 95% CI, 1·02-1·36; P<0·05). However, none of the investigated variables evolved as an independent predictor of cardiovascular morbidity and mortality. CONCLUSION: E(m) appears to be a sensitive echocardiographic index in identifying non-diabetic patients with AMI at risk of new cardiovascular events.

Feasibility of myocardial performance index for evaluation of left ventricular function during dobutamine stress echocardiography before and after coronary artery bypass grafting.

AIMS: Myocardial performance index (MPI) is a measure of combined systolic and diastolic myocardial function. In patients with coronary artery disease (CAD) an increase in MPI is consistent with myocardial dysfunction. The objectives of this study were to characterize the changes in MPI after coronary artery bypass graft (CABG) at rest and at peak dobutamine stress echocardiography (DSE). METHODS AND RESULTS: Thirty-six patients diagnosed with CAD and accepted for CABG were studied by standard echocardiography and DSE 1 month prior and 3 month after CABG. The MPI was calculated using pulsed-wave tissue Doppler imaging (PW-TDI) of the left ventricular (LV) wall-motion velocity. At baseline, ejection fraction (EF; 42.7 ± 8%) and wall-motion score index (WMSI; 1.1 ± 0.2) were impaired at rest as well as at peak DSE (EF; 49.2 ± 9 and WMSI 1.4 ± 0.2). MPI was prolonged both at rest (0.61 ± 0.13) and at peak DSE (0.78 ± 0.16). After CABG, EF and WMSI did not improve at rest (43.7 ± 8% and 1.1 ± 0.2, respectively). On the other hand, MPI improved substantially both at rest (0.45 ± 0.08; P < 0.001) and at peak DSE (0.56 ± 0.1; P < 0.001). At peak DSE an improvement of EF (54.2 ± 9; P < 0.05) and WMSI (1.1 ± 0.16; P < 0.001) was seen as well. CONCLUSION: Myocardial performance index shows significant improvement after CABG in patients with CAD both at rest and peak DSE and appears to be a sensitive measure of myocardial function.

Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function.

OBJECTIVES: Myocardial function can be evaluated using color-coded tissue velocity imaging (TVI) to analyze the longitudinal myocardial velocity profile, and by expressing the motion of the atrioventricular plane during a cardiac cycle as coordinated events in the cardiac state diagram (CSD). The objective of this study was to establish gestational age specific reference values for fetal TVI measurements and to introduce the CSD as a potential aid in fetal myocardial evaluation. METHODS: TVI recordings from 125 healthy fetuses, at 18 to 42 weeks of gestation, were performed with the transducer perpendicular to the apex to provide a four-chamber view. The myocardial velocity data was extracted from the basal segment of septum as well as the left and right ventricular free wall for subsequent offline analysis. RESULTS: During a cardiac cycle the longitudinal peak velocities of septum increased with gestational age, as did the peak velocities of the left and right ventricular free wall, except for the peak velocity of post ejection. The duration of rapid filling and atrial contraction increased during pregnancy while the duration of post ejection decreased. The duration of pre ejection and ventricular ejection did not change significantly with gestational age. CONCLUSION: Evaluating fetal systolic and diastolic performance using TVI together with CSD could contribute to increase the knowledge and understanding of fetal myocardial function and dysfunction. The pre and post ejection phases are the variables most likely to indicate fetuses with abnormal myocardial function.

Visualization of multimodal polymer-shelled contrast agents using ultrasound contrast sequences: an experimental study in a tissue mimicking flow phantom.

BACKGROUND: A multimodal polymer-shelled contrast agent (CA) with target specific potential was recently developed and tested for its acoustic properties in a single element transducer setup. Since the developed polymeric CA has different chemical composition than the commercially available CAs, there is an interest to study its acoustic response when using clinical ultrasound systems. The aim of this study was therefore to investigate the acoustic response by studying the visualization capability and shadowing effect of three polymer-shelled CAs when using optimized sequences for contrast imaging. METHODS: The acoustic response of three types of the multimodal CA was evaluated in a tissue mimicking flow phantom setup by measuring contrast to tissue ratio (CTR) and acoustic shadowing using five image sequences optimized for contrast imaging. The measurements were performed over a mechanical index (MI) range of 0.2-1.2 at three CA concentrations (106, 105, 104 microbubbles/ml). RESULTS: The CTR-values were found to vary with the applied contrast sequence, MI and CA. The highest CTR-values were obtained when a contrast sequence optimized for higher MI imaging was used. At a CA concentration of 106 microbubbles/ml, acoustic shadowing was observed for all contrast sequences and CAs. CONCLUSIONS: The CAs showed the potential to enhance ultrasound images generated by available contrast sequences. A CA concentration of 106 MBs/ml implies a non-linear relation between MB concentration and image intensity.

The cardiac state diagram as a novel approach for the evaluation of pre- and post-ejection phases of the cardiac cycle in asphyxiated fetal lambs.

The aim of this study was to investigate myocardial wall motion using echocardiography and color-coded tissue velocity imaging and to generate a cardiac state diagram for evaluation of the duration of the pre- and post-ejection phases in asphyxiated fetal lambs. Six near-term lambs were partly exteriorized and brought to cardiac arrest through asphyxia. Echocardiography measurements were recorded simultaneously with arterial blood sampling for lactate and blood gases. All fetal lambs exhibited prolongation of the pre- and post-ejection phases at the time when the most pronounced changes in lactate concentration and pH occurred. The mean change in duration of the pre- and post-ejection phases for all fetal lambs was 36 ± 7 ms (p < 0.002) and 77 ± 17 ms (p < 0.019), respectively, and the percentage change was 50% (p < 0.001) and 38% (p < 0.049), respectively. As asphyxia progressed in fetal lambs, the duration of the pre- and post-ejection phases increased. The cardiac state diagram has the potential to be a comprehensible tool for detecting fetal asphyxia.

Evaluation of ultrasound Tissue Velocity Imaging: a phantom study of velocity estimation in skeletal muscle low-level contractions.

BACKGROUND: Tissue Velocity Imaging (TVI) is an ultrasound based technique used for quantitative analysis of the cardiac function and has earlier been evaluated according to myocardial velocities. Recent years several studies have reported applying TVI in the analysis of skeletal muscles. Skeletal tissue velocities can be very low. In particular, when performing isometric contractions or contractions of low force level the velocities may be much lower compared to the myocardial tissue velocities. METHODS: In this study TVI was evaluated for estimation of tissue velocities below the typical myocardial velocities. An in-house phantom was used to see how different PRF-settings affected the accuracy of the velocity estimations. RESULTS: With phantom peak velocity at 0.03 cm/s the error ranged from 31% up to 313% with the different PRF-settings in this study. For the peak velocities at 0.17 cm/s and 0.26 cm/s there was no difference in error with tested PFR settings, it is kept approximately around 20%. CONCLUSIONS: The results from the present study showed that the PRF setting did not seem to affect the accuracy of the velocity estimation at tissue velocities above 0.17 cm/s. However at lower velocities (0.03 cm/s) the setting was crucial for the accuracy. The PRF should therefore preferable be reduced when the method is applied in low-level muscle contraction.

Left ventricular mechanical dyssynchrony in patients with different stages of chronic kidney disease and the effects of hemodialysis.

Left ventricular (LV) dyssynchrony is a known cause of mortality in patients with heart failure and may possibly play a similar role in patients with chronic kidney disease (CKD) in whom sudden death is one of the most common and as yet not fully explained cause of death. LV synchronicity and its relationship with increased volume load and various biomarkers was analyzed in 145 patients including 53 patients with CKD stages 3 and 4 and in 92 CKD stage 5 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) using color tissue Doppler imaging and tissue synchronization imaging. The HD patients were evaluated both before and after a single HD session. LV dyssynchrony was defined as a regional difference in time to peak systolic myocardial velocity, between 12 LV segments > 105 milliseconds. LV dyssynchrony was present in 54% of the patients with no difference between CKD 3 and 4 (58%), HD (48%), and PD (51%). LV dyssynchrony was independently associated with LV mass index and increased estimation of LV end-diastolic pressure. A single HD session resulted in significant changes in LV synchronicity variables-with improvement in 50% of the patients-especially in patients with higher myocardial systolic velocities and lower LV mass index. Abnormalities in LV synchronicity are highly prevalent in CKD patients already prior to dialysis treatment and are associated with LV hypertrophy, LV dysfunction and load conditions, underlining the importance of volume status for LV synchronicity in CKD patients.

The value of E/Em ratio in the estimation of left ventricular filling pressures: impact of acute load reduction: a comparative simultaneous echocardiographic and catheterization study.

BACKGROUND: The ratio of the early transmitral flow velocity to the early diastolic tissue velocity (E/Em) has been suggested as a reliable estimate of left ventricular diastolic pressures (LVDP). However, the evidence regarding the ability of E/Em to detect LVDP changes is relatively equivocal. Our aim was to evaluate the validity of the ratio following acute load reduction. METHODS AND RESULTS: 68 consecutive patients referred for coronary angiography underwent LV catheterization and echocardiography simultaneously. Doppler signals of transmitral flow and spectral TD signals at the level of the mitral annulus were obtained before and directly after intravenous administration of nitroglycerin (NTG). The predictive ability of E/Em to identify elevated LVDP was modest (area under curve=0.71 ± 0.08, p<0.01). The index was more strongly associated with LVDP in patients with reduced ejection fraction (EF)<55% (r=0.68; p<0.01) than in patients with normal EF. Following NTG, E/Em lacked any predictive potential for elevated LVDP whereas changes LVDP could not be reliably tracked using E/Em. CONCLUSION: The predictive capacity of E/Em for elevated LVDP was weak and declined significantly following acute reduction in LV load. Changes in LVDP were not reliably predicted by E/Em. The current findings derived from a real-world patient population with relatively high filling pressures indicate that E/Em may not be sufficiently robust to be employed as a single non-invasive estimate of LVDP nor for monitoring load reducing medical therapy.

Changes in circulating biomarkers during a single hemodialysis session.

The hemodialysis (HD) procedure induces an inflammatory response potentially contributing to cardiovascular disease. Here we investigated the acute impact of HD on circulating biomarkers. Circulating biomarkers (small solutes, middle molecular-sized peptides, and proteins) related to inflammation, oxidative stress, and vascular calcification (VC) were measured before and after a single session of HD in 45 clinically stable patients. Concentrations were corrected for ultrafiltration-induced hemoconcentration. Among vascular calcification-related biomarkers, osteoprotegerin and fetuin-A remained unchanged while fibroblast growth factor-23 (FGF23) decreased by -19%. Changes of FGF23 and changes of phosphate correlated (ρ = 0.61, P < 0.001). While C-reactive protein did not change, interleukin-6 (IL-6) increased by 14% and pentraxin 3 (PTX3) increased by 45%. IL-6 and PTX3 appear to be valid biomarkers of the intradialytic inflammatory response. VC-related markers were in general not affected by the single HD session; however, the observed correlation between acute changes of FGF-23 and phosphate during HD warrants further studies.

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study.

BACKGROUND: Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI). METHODS: TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201-273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis. RESULTS: Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E'/A' ratio also increased with gestational age, while a longitudinal shortening was demonstrated. CONCLUSIONS: Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.

Role of N-terminal pro-brain natriuretic peptide in ST-segment elevation myocardial infarction: experience from a tertiary centre in India.

BACKGROUND: Role of biomarkers in ST-segment elevation myocardial infarction (STEMI) is paramount, as they aid in diagnosis and gauge prognosis of the disease. In this project, we sought to study the short-term outcome and clinical associates of N-terminal pro-brain natriuretic peptide (NT-proBNP) in the setting of STEMI at a tertiary center in India. METHODS: In all, 173 STEMI patients (mean age: 57 ± 12 years, 38 women) had their NT-proBNP assayed in addition to troponins and high-sensitive C-reactive protein. Subjects were divided according to NT-proBNP levels into 2 groups: group 1 (NT-proBNP ≤100 pg/mL) and group 2 (NT-proBNP >100 pg/mL). RESULTS: NT-proBNP values (pg/mL) were elevated in group 2 (group 1: 61.7 ± 6.2; group 2: 1006.5 ± 990.6, P < 0.0001). Significantly greater number of females had elevated NT-proBNP (P < 0.05) that could be predicted by the duration of chest pain related to STEMI (area under the curve: 0.72), and age at presentation (area under the curve: 0.66). Multiple regression analysis showed a strong inverse association between NT-proBNP and left ventricular ejection fraction and a strong positive association between the peptide and high-sensitive C-reactive protein. A significant positive association was also noted between NT-proBNP and troponin I (all P < 0.05, Global R = 0.47). Diabetes mellitus and/or hypertension, and infarction localization showed no effect on NT-proBNP levels along with death, primary coronary intervention-related bleeding, and arrhythmias, (χ, P = ns). CONCLUSIONS: The data suggest that women are more likely to have increased NT-proBNP while presenting with STEMI. Duration of chest pain and age at presentation are the best predictors of elevated NT-proBNP, though without much bearing on short-term morbidity and mortality.

Ultrasound-based radial and longitudinal strain estimation of the carotid artery: a feasibility study.

Ultrasound-based estimation of arterial wall elasticity is commonly used to assess arterial stiffness. However, previous elastography studies have mostly addressed radial strain measurements, and the longitudinal strain has been more or less ignored. This study shows the feasibility of a speckle-tracking-based algorithm for simultaneous estimation of radial and longitudinal strain in the carotid artery in silico. Additionally, these results were preliminarily confirmed in vivo.

Arterial vasodilatory and ventricular diastolic reserves determine the stroke volume response to exercise in elderly female hypertensive patients.

Elderly female hypertensives with arterial stiffening constitute a majority of patients with heart failure with preserved ejection fraction (HFpEF), a condition characterized by inability to increase cardiac stroke volume (SV) with physical exercise. As SV is determined by the interaction between the left ventricle (LV) and its load, we wished to study the role of arterial hemodynamics for exertional SV reserve in patients at high risk of HFpEF. Twenty-one elderly (67 ± 9 yr) female hypertensive patients were studied at rest and during supine bicycle stress using echocardiography including pulsed-wave Doppler to record flow in the LV outflow tract and arterial tonometry for central arterial pressure waveforms. Arterial compliance was estimated based on an exponential relationship between pressure and volume. The ratio of aortic pressure-to-flow in early systole was used to derive characteristic impedance, which was subsequently subtracted from total resistance (mean arterial pressure/cardiac output) to yield systemic vascular resistance (SVR). It was found that patients with depressed SV reserve (NoRes; reserve <15%; n = 10) showed decreased arterial compliance during exercise, while patients with SV reserve ≥15% (Res; n = 11) showed increased compliance. Exercise produced parallel increases in LV end-diastolic volume and arterial volume in Res patients while NoRes patients exhibited a lesser decrease in SVR and a drop in effective arterial volume. Poor SV reserve in elderly female hypertensives is due to simultaneous failure of LV preload and arterial vasodilatory reserves. Abnormal arterial function contributes to a high risk of HFpEF in these patients.