Vortex Formation Time is a Novel Measure for Early Detection of Diastolic Abnormalities in Adolescents with Hypertension.

Pediatric hypertension (HTN) has demonstrated an upward trend in recent years. Adolescent HTN has been linked to adult HTN, cardiovascular disease, and other health conditions. Thus, it is essential that HTN and its associated cardiac abnormalities be diagnosed and treated early to minimize lifelong adverse effects. In this study, we evaluated whether vortex formation time (VFT), a validated echocardiogram measure of left ventricular diastolic dysfunction, correlated with ambulatory blood pressure monitoring (ABPM) and HTN in adolescents. Echocardiogram data including systolic and diastolic function indices and ABPM data from 2015 to 2022 in adolescents age 13-21 years were analyzed retrospectively. We found that VFT was significantly lower in adolescents with HTN compared to those without HTN (3.69 ± 1.39 vs. 4.50 ± 1.73, p = 0.02). Standard echocardiographic indices of systolic and diastolic function were similar between the two groups, except indexed left atrial volume. Higher overall systolic blood pressure (SBP) (ß = - 0.01, CI - 0.02, - 2.2 × 10-3, p = 0.02), mean wake SBP (ß = - 0.01, CI - 0.02, - 9.4 × 10-4, p = 0.03), and mean sleep SBP (ß = - 0.01, CI - 0.02, - 1.2 × 10-3, p = 0.03) were significantly associated with lower VFT. This study demonstrates that VFT correlates to ABPM data and can be used a novel diagnostic measure in adolescents with HTN.

Age-related changes in diastolic function in children: Echocardiographic association with vortex formation time.

BACKGROUND: This study aims to understand the age-related changes in vortex formation time (VFT) index in children, and thus, describe the ranges of VFT in different pediatric age groups with the ultimate goal of assessment of diastolic function. METHODS AND RESULTS: Transthoracic echocardiograms in healthy (n = 84) subjects from birth to 20 years were analyzed to compute VFT and diastolic performance. LV apical and short-axis views were used. Three separate measurements were performed, and the mean was used to derive VFT and other indices. Statistical comparisons were made amongst the groups, stratified by age. RESULTS: Vortex formation times in neonates (median 1.79, interquartile range 1.31-1.92) and infants (1.38, 1.07-1.72) were found to be significantly lower (P < .05) than the older age groups (1-5 years 2.47, 1.87-2.94, 5-10 years 2.18, 1.89-2.53, 10-20 years 2.34, 1.84-2.96). The changes in VFT correlate to the changes in diastolic function in children. CONCLUSION: Our results show that unlike adults, VFT changes along with the growth-related myocardial adaptations in children, and its range may be used to evaluate diastolic function. The present study is the first to test the significance of the trans-mitral VFT in children by comparing different age groups of healthy subjects.

Advanced Age Attenuates Left Ventricular Filling Efficiency Quantified Using Vortex Formation Time: A Study of Octogenarians With Normal Left Ventricular Systolic Function Undergoing Coronary Artery Surgery.

OBJECTIVE: Blood flow across the mitral valve during early left ventricular (LV) filling produces a 3-dimensional rotational fluid body, known as a vortex ring, that enhances LV filling efficiency. Diastolic dysfunction is common in elderly patients, but the influence of advanced age on vortex formation is unknown. The authors tested the hypothesis that advanced age is associated with a reduction in LV filling efficiency quantified using vortex formation time (VFT) in octogenarians undergoing coronary artery bypass graft (CABG) surgery. DESIGN: Observational study. SETTING: Veterans Affairs medical center. PARTICIPANTS: After institutional review board approval, octogenarians (n = 7; 82 ± 2 year [mean ± standard deviation]; ejection fraction 56% ± 7%) without valve disease or atrial arrhythmias undergoing CABG were compared with a younger cohort (n = 7; 55 ± 6 year; ejection fraction 57% ± 7%) who were undergoing coronary revascularization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients were monitored using radial and pulmonary arterial catheters and transesophageal echocardiography. Peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler echocardiography to determine E/A, atrial filling fraction (ß), and E wave deceleration time. Pulse-wave Doppler also was used to measure pulmonary venous blood flow during systole and diastole. Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal LV bicommissural and long-axis transesophageal echocardiography imaging planes, respectively. VFT was calculated as 4 × (1 - ß) × SV/(πD3), where SV is the stroke volume measured using thermodilution. Systemic and pulmonary hemodynamics, LV diastolic function, and VFT were determined during steady-state conditions 30 minutes before cardiopulmonary bypass. A delayed relaxation pattern of LV filling (E/A 0.81 ± 0.16 v 1.29 ± 0.19, p = 0.00015; ß 0.44 ± 0.05 v 0.35 ± 0.03, p = 0.0008; E wave deceleration time 294 ± 58 v 166 ± 28 ms, p < 0.0001; ratio of peak pulmonary venous systolic and diastolic blood flow velocity 1.42 ± 0.23 v 1.14 ± 0.20, p = 0.0255) was observed in octogenarians compared with younger patients. Mitral valve diameter was similar between groups (2.7 ± 0.2 and 2.6 ± 0.2 cm, respectively, in octogenarians v younger patients, p = 0.299). VFT was reduced in octogenarians compared with younger patients (3.0 ± 0.9 v 4.5 ± 1.2; p = 0.0171). An inverse correlation between age and VFT was shown using linear regression analysis (VFT = -0.0627 × age + 8.24; r2 = 0.408; p = 0.0139). CONCLUSION: The results indicate that LV filling efficiency quantified using VFT is reduced in octogenarians compared with younger patients undergoing coronary artery bypass grafting.

Moderate Aortic Valvular Insufficiency Invalidates Vortex Formation Time as an Index of Left Ventricular Filling Efficiency in Patients With Severe Degenerative Calcific Aortic Stenosis Undergoing Aortic Valve Replacement.

OBJECTIVE: Transmitral blood flow produces a vortex ring (quantified using vortex formation time [VFT]) that enhances the efficiency of left ventricular (LV) filling. VFT is attenuated in LV hypertrophy resulting from aortic valve stenosis (AS) versus normal LV geometry. Many patients with AS also have aortic insufficiency (AI). The authors tested the hypothesis that moderate AI falsely elevates VFT by partially inhibiting mitral leaflet opening in patients with AS. DESIGN: Observational study. SETTING: Veterans Affairs medical center. PARTICIPANTS: Patients with AS in the presence or absence of moderate AI (n = 8 per group) undergoing aortic valve replacement (AVR) were studied after institutional review board approval. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Under general anesthesia, peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler transesophageal echocardiography (TEE) to determine E/A and atrial filling fraction (beta). Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal bicommissural (transcommissural anterior-lateral-posterior medial) and LV long-axis (anterior-posterior) TEE imaging planes, respectively. VFT was calculated as 4·(1-beta)·SV/πD(3), where SV = stroke volume measured using thermodilution. Hemodynamics, diastolic function, and VFT were determined during steady-state conditions before cardiopulmonary bypass. The severity of AS (mean and peak pressure gradients, peak transvalvular jet velocity, aortic valve area) and diastolic function (E/A, beta) were similar between groups. Moderate centrally directed AI was present in 8 patients with AS (ratio of regurgitant jet width to LV outflow tract diameter of 36±6%). Pulse pressure and mean pulmonary artery pressure were elevated in patients with versus without AI, but no other differences in hemodynamics were observed. Mitral valve minor and major axis lengths, diameter, and area were reduced in the presence versus the absence of AI. VFT was increased significantly (5.7±1.7 v 3.2±0.6; p = 0.00108) in patients with AS and AI compared with AS alone. CONCLUSION: Moderate AI falsely elevates VFT in patients with severe AS undergoing AVR by partially inhibiting mitral valve opening. VFT may be an unreliable index of LV filling efficiency with competitive diastolic flow into the LV.

Vortex formation time in female athletes.

Regular, vigorous physical activity can have a significant impact on cardiac function, leading to cardiac morphological alterations that may be challenging to distinguish from pathological changes. Therefore, new screening methods are needed to accurately differentiate between adaptive changes and pathological alterations in athletes. Vortex formation time (VFT) is an emerging method that shows potential in this regard, as it involves the formation of a rotating vortex ring in the left ventricle during the early filling phase of diastole. In this study, we investigated the difference in VFT between two groups of women: professional handball players and healthy middle-aged female athletes, along with their corresponding control groups. By using echocardiography-Doppler analysis of the heart, VFT was calculated based on the left ventricular ejection fraction, the ratio between the end-diastolic volume and the diameter of the mitral annulus, and the ratio of the atrial contraction volume to the total inflow via the mitral valve. The study reveals a significant increase in VFT in both professional handball players and middle-aged female athletes compared to their respective control groups. Moreover, statistically significant differences between handball players and middle-aged female athletes were observed, indicating that the level of physical activity may affect the VFT. These results suggest that VFT could be a promising screening tool for identifying cardiac adaptations due to long-term vigorous training, potentially enabling more accurate diagnoses of cardiac morphological alterations in athletes.

Chronic pressure-overload hypertrophy attenuates vortex formation time in patients with severe aortic stenosis and preserved left ventricular systolic function undergoing aortic valve replacement.

OBJECTIVE: Transmitral blood flow produces a vortex ring that enhances the hydraulic efficiency of early left ventricular (LV) filling. The effect of pressure-overload hypertrophy on the duration of LV vortex ring formation (vortex formation time [VFT]) is unknown. The current investigation tested the hypothesis that chronic LV pressure-overload hypertrophy produced by severe aortic stenosis (AS) reduces VFT in patients with preserved LV systolic function undergoing aortic valve replacement. DESIGN: Observational study. SETTING: Veterans Affairs Medical Center. PARTICIPANTS: After the Institutional Review Board's approval, 8 patients (7 men and 1 woman; age, 62±5 y; and ejection fraction, 59%±5%) with AS (peak pressure gradient, 81±22 mmHg; aortic valve area, 0.78±0.25 cm(2)) scheduled for aortic valve replacement were compared with 8 patients (all men; age, 63±3 y; and ejection fraction, 60%±7%) without AS undergoing coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Under general anesthesia, peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler echocardiography to determine E/A and atrial filling fraction (ß). Mitral valve diameter (D) was calculated as the average of minor and major axis lengths obtained in the midesophageal bicommissural and long-axis transesophageal echocardiography imaging planes, respectively. Posterior wall thickness (PWT) was measured at end-diastole using M-mode echocardiography. VFT was calculated as 4×(1-ß)×SV/πD(3), where SV = stroke volume measured using thermodilution. Systemic and pulmonary hemodynamics, LV diastolic function, PWT, and VFT were determined during steady-state conditions 30 minutes before cardiopulmonary bypass. Early LV filling was attenuated in patients with AS (eg, E/A, 0.77±0.11 compared with 1.23±0.13; ß, 0.43±0.09 compared with 0.35±0.02; p<0.05 for each). LV hypertrophy was observed (PWT, 1.4±0.1 cm compared with 1.1±0.2 cm; p<0.05) and VFT was lower (3.0±0.9 v 4.3±0.5; p<0.05) in patients with versus without AS. Linear regression analysis showed a significant correlation between VFT and PWT (VFT = -2.57 ×PWT + 6.81; r(2) = 0.345; p = 0.017). CONCLUSION: The results indicated that pressure-overload hypertrophy produced by AS reduced VFT in patients with normal LV systolic function undergoing aortic valve replacement.

Left ventricular vortex formation time: emerging clinical applications and limitations.

Vortex formation during left ventricular diastolic filling may provide clinically useful insights into cardiac health. In recent years, there has been growing interest in the measurement of vortex formation time (VFT), especially because it is derived noninvasively. There are important applications of VFT in valvular heart disease, athletic physiology, heart failure and hypertrophic cardiomyopathy. The formation of the vortex as fluid propagates into the left ventricle from the left atrium is important for efficient fluid transport. Quantifying VFT may thus help in evaluating and understanding disease and pathophysiological processes.

Intraventricular Flow Simulations in Singular Right Ventricles Reveal Deteriorated Washout and Low Vortex Formation.

PURPOSE: Patients with a functionally univentricular heart represent one of the most common severe cardiac lesions with a prevalence of 3 per 10,000 live births. Hemodynamics of the singular ventricle is a major research topic in cardiology and there exists a relationship between fluid dynamical features and cardiac behavior in health and disease. The aim of the present work was to compare intraventricular flow in single right ventricle (SRV) patients and subjects with healthy left hearts (LV) through patient-specific CFD simulations. METHODS: Three-dimensional real-time echocardiographic images were obtained for five SRV patients and two healthy subjects and CFD simulations with a moving mesh methodology were performed. Intraventricular vortex formation and vortex formation time (VFT) as well as the turbulent kinetic energy (TKE) and ventricular washout were evaluated. RESULTS: The results show significantly lower values for the VFT and the TKE in SRV patients compared with healthy LV subjects. Furthermore, vortex formation does not progress to the apex in SRV patients. These findings were confirmed by a significantly lower washout in SRV patients. CONCLUSIONS: The study pinpoints the intriguing role of intraventricular flows to characterize performance of SRVs that goes beyond standard clinical metrics such as ejection fraction.

Vortex formation time as an index of left ventricular filling efficiency: comparison between children volunteers and patients with tetralogy of Fallot.

Background: Vortex formation time (VFT) had been considered a useful marker for assessing diastolic performance. the VFT assessment of diastolic function using four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has not been used in repair of tetralogy of Fallot (rTOF) patient. The aims of this study were as follows: (I) establish reference ranges for VFT measurements in healthy children and adolescents using 4D flow CMR imaging; and (II) analyze VFT parameters to assess diastole dysfunction in rTOF patients group. Methods: We acquired the CMR data was of 62 healthy participants (aged 6-18 years; male: 40, female: 22) and 20 patients with rTOF (aged 10-13 years; male: 15, female: 5) using 4D flow and cine sequence in routine chamber view. The VFT was calculated based on comparison of different algorithms from cine measurements (VFTvolume) and 4D flow measurements (VFTblood). Then, VFT measurements were compared to subject peak filling rate (PFR), age, and cardiac mass using simple linear regression and multiple regression analyses. Data were also categorized according to age for VFT and cardiac functional assessment comparisons between 3 age groups (Group 1: 6-9 years; Group 2: 10-13 years; Group 3: 14-18 years). The correlation of VFT and cardiac function parameters were analyzed in the rTOF group. Results: Normal mean value of VFTvolume and VFTblood were 4.25±0.92 and 3.77±1.11 in healthy children participants. The VFTvolume was correlated with VFTblood (r=0.61, P<0.001). There was a moderately significant correlation between VFTvolume and PFR (r=0.46, P<0.001) and between VFTblood and PFR (r=0.47, P<0.001), age (r=0.41, P=0.002) and left ventricular (LV) mass (r=0.48, P<0.001). Multiple regression analyses demonstrated that VFTvolume was independently associated with PFR (T=2.239; P<0.05) and VFTblood (T=4.361; P<0.001). There was a significant difference in VFTvolume between healthy controls and rTOF patients (5.44±1.93 vs. 4.27±0.88, P=0.018). Conclusions: The VFT measurements showed that the LV that had appropriate space to form the optimal vortex ring in normal children and adolescents aged 6-18 years old. The VFTvolume could potentially be helpful in improving our understanding of LV diastolic dysfunction in rTOF patients.

Optimal vortex formation time index in mitral valve stenosis.

Left ventricular vortex formation time (VFT) is a novel dimensionless index of flow propagation during left ventricular diastole, which has been demonstrated to be useful in heart failure and cardiomyopathy. In mitral stenosis (MS), flow propagation in the LV may be suboptimal. We studied VFT in varying degrees of MS. Echocardiography was performed on 20 healthy controls and 50 cases of rheumatic MS. Patients with atrial fibrillation, LV ejection fraction < 50% and other valvular heart diseases were excluded. VFT was obtained using the length-to-diameter ratio (L/D), where L is the continuous-wave Doppler velocity time integral stroke distance, divided by D, the mitral leaflet separation index. This was correlated against varying degrees of MS severity, left atrial (LA) volume and function. In controls, VFT was 3.92 ± 2.00 (optimal range) and was higher (suboptimal) with increasing severity of mitral stenosis (4.98 ± 2.43 in mild MS; 7.22 ± 2.98 in moderate MS; 11.55 ± 2.67 in severe MS, p < 0.001). VFT negatively correlated with mitral valve area (R2 = 0.463, p < 0.001) and total LA emptying fraction (R2 = 0.348, p < 0.001), and positively correlated with LA volume index (R2 = 0.440, p < 0.001) and mean transmitral pressure gradient (R2 = 0.336, p < 0.001). More severe MS correlated with suboptimal (higher) VFT. The restricted mitral valve opening may disrupt vortex formation and optimal fluid propagation in the LV. Despite the compensatory increase in LA size with increasingly severe MS, reduced LA function also contributed to the suboptimal LV vortex formation.

The Effect of Dobutamine Stress Testing on Vortex Formation Time in Patients Evaluated for Ischemia.

Vortex formation time (VFT) is a dimensionless index used to quantify duration of vortex ring formation during diastole. We sought to investigate the effect of pharmaceutical stress on VFT in patients evaluated for ischemia. For this purpose, a standard dobutamine stress echo (DSE) protocol was performed in 50 consecutive patients, and VFT was calculated at rest and at peak. VFT was calculated from echocardiography measurements using a previously developed mathematical equation. VFTi was calculated as the percentage of change of VFTpeak, compared with VFTrest. Mean VFTrest was 2.46 (0.73) and mean VFTpeak 1.67 (0.57) with mean VFTi - 30.0% (19.8). In 14 (28%) patients, an ischemic response (DSE+) was documented. VFTi was significantly lower in DSE+ patients a finding which remained significant in the multivariate analysis after adjusting for age, sex, hypertension, diabetes, history of coronary artery disease, and relative increase of heart rate during stress. Graphical Abstract.

Left ventricular vortex formation time in elite athletes.

Vortex formation time (VFT) is a continuous measure of the left ventricular (LV) filling that integrates all phases of diastole. This has been previously studied in patients with heart failure. This study examined the differences in VFT between healthy controls and elite athletes. We compared echocardiographic indices between elite male athletes (n = 41) and age-, weight- and sex-matched sedentary volunteers (n = 22). VFT was obtained using the validated formula: 4 × (1 - ß)/π × α3 × LVEF, where ß is the fraction of total transmitral diastolic stroke volume contributed by atrial contraction (assessed by time velocity integral of the mitral E- and A-waves) and α is the biplane end-diastolic volume (EDV)1/3 divided by mitral annular diameter during early diastole. Diastolic function was measured by the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (e') (E/e' ratio) and the ratio of E to mitral peak velocity of late filling (A) (E/A ratio). The heart rate was lower (63 ± 10 vs. 74 ± 6 beats per minute, p < 0.001) and the LV end diastolic diameter was larger in athletes as compared to controls (56 ± 3 vs. 50 ± 4 mm, p < 0.001). The VFT was lower in the sedentary group compared to athletes (3.1 ± 0.4 vs. 4.0 ± 0.8, p < 0.001). Similarly, E/e' was higher in sedentary controls compared to athletes (7.5 ± 1.8 vs 4.2 ± 1.0, p < 0.001). Furthermore, there was a modest correlation between VFT and E/A (r = 0.47, p < 0.001) as well as E/e' (r = - 0.33, p = 0.012). In conclusion, the VFT was elevated among elite athletes compared to healthy sedentary controls.

Left ventricular vortex formation time in elite athletes: novel predictor of myocardial performance.

BACKGROUND: Efficient transportation of blood through the left ventricle (LV) during diastole depends on vortex formation. Vortex formation time (VFT) can be measured by echocardiography as a dimensionless index. As elite athletes have supranormal diastolic LV function, we aim to assess resting and post-exercise VFT in these athletes and hypothesised that VFT may predict myocardial performance immediately post-exercise. METHOD: Subjects were world class speedskaters training for the Winter Olympic Games. Echocardiographic measurements were obtained before and immediately after 3000 m of racing. VFT was computed as 4×(1-ß)/π×α³×left ventricle ejection fraction where ß is the fraction of diastolic stroke volume contributed by atrial contraction, α is the biplane end diastolic volume (EDV)1/3 divided by mitral annular diameter during early diastole. RESULTS: Baseline VFT was 2.6±0.7 (n=24, age 22±3 years, 67% males). Post-exercise, heart rates increased (64±10 vs 89±12 beats/min, p<0.01); however, VFT was unchanged (2.9±1.0, p>0.05). VFT at rest correlated modestly with post-exertion early diastolic mitral in-flow velocity (E; r=0.59, p=0.01), tissue Doppler-derived early mitral annular velocity (E'; septal and lateral, both r=0.59, p=0.01) and systolic annular velocity (S'; septal: r=0.46, p=0.02 and lateral: r=0.48, p=0.02) but not late diastolic mitral in-flow velocity (A; r=0.06, p>0.05) or annular velocity (A'; septal: r=0.34, p=NS and lateral: r=0.35, p>0.05). CONCLUSION: There was no significant difference between VFT at rest and immediately post-exercise. However, VFT at rest correlated with immediate post-exercise augmented systolic and early diastolic tissue Doppler indicators of myocardial performance in elite athletes.

New echocardiographic parameters in the diagnosis of heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) is a serious clinical disease. The pathophysiology of HFpEF is complex, and specific diagnostic criteria have evolved over time. Limited data are available on the quantification of diastolic function using two-dimensional real-time echocardiography, and a simple parameter has not yet been established. The aim of this work is to evaluate new echocardiographic parameters-the diastolic wall strain of the posterior wall (DWS PW) and the vortex formation time (VFT). Echocardiographic data from 111 subjects with exertional dyspnea and normal left ejection fraction (Group A) and 20 healthy volunteers (Group B) were retrospectively evaluated. In addition to the standard parameters used in the diagnosis of HFpEF, DWS PW and VFT were assessed in all patients. HFpEF was diagnosed in 38 patients with dyspnea (Group A1). The remaining 73 patients did not meet the established criteria for a positive diagnosis of HFpEF (Group A2). We discovered that both observed parameters were significantly lower in patients with HFpEF than in other groups. Multivariate analysis revealed that both DWS PW and VFT independently predicted the presence of HFpEF. DWS PW and VFT are simple parameters in the evaluation of diastolic function and may play a potential role as a part of an integrated approach to the assessment of HFpEF.