Evaluation of left ventricular rotation in obese subjects by velocity vector imaging

Diagnostic imaging in the management of patients with metabolic syndrome

Metabolic syndrome (MetS) is the constellation of metabolic risk factors that might foster development of type 2 diabetes and cardiovascular disease. Abdominal obesity and insulin resistance play a prominent role among all metabolic traits of MetS. Because intervention including weight loss can reduce these morbidity and mortality in MetS, early detection of the severity and complications of MetS could be useful. Recent advances in imaging modalities have provided significant insight into the development and progression of abdominal obesity and insulin resistance, as well as target organ injuries. The purpose of this review is to summarize advances in diagnostic imaging modalities in MetS that can be applied for evaluating each components and target organs. This may help in early detection, monitoring target organ injury, and in turn developing novel therapeutic target to alleviate and avert them.

Left ventricular function of patients with pregnancy-induced hypertension evaluated using velocity vector imaging echocardiography and N-terminal pro-brain natriuretic peptide

PURPOSE

To investigate whether acute and transient pressure overload in patients with pregnancy-induced hypertension (PIH) affects left ventricular (LV) systolic function.

METHODS

From pregnancy to 3 months after delivery, 82 patients were analyzed: 27, 25, and 30 with gestational hypertension, preeclampsia, and the healthy control group, respectively. Conventional echocardiography and velocity vector imaging (VVI) were performed, and blood levels of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) were analyzed.

RESULTS

Compared with the control group, patients with gestational hypertension had significantly lower mean LV peak global longitudinal strain. Importantly, during both pregnancy and after delivery, patients with preeclampsia had significantly lower global longitudinal, circumferential, and radial strain compared with the control group. The NT-pro-BNP levels were significantly higher in patients with PIH compared with normotensive pregnancies, and this situation continued for 3 months after delivery in women with preeclampsia.

CONCLUSIONS

In pregnancies complicated by pregnancy-induced hypertension, especially preeclampsia, the systolic function is impaired and NT-pro-BNP levels are elevated compared with normal pregnancy. Velocity vector imaging (VVI) is more sensitive than left ventricular ejection fraction to evaluate heart function in patients with PIH.

Four-dimensional echocardiography area strain combined with exercise stress echocardiography to evaluate left ventricular regional systolic function in patients with mild single vessel coronary artery stenosis

BACKGROUND

The aim of this prospective study was to assess the diagnosis value of four-dimensional echocardiography area strain (AS) combined with exercise stress echocardiography to evaluate left ventricular regional systolic function in patients with mild single vessel coronary artery stenosis.

METHODS

Based on treadmill exercise load status, two-dimensional conventional echocardiography and four-dimensional echocardiography area strain were performed on patients suspected coronary artery disease before coronary angiogram. Thirty patients (case group) with mild left anterior descending coronary artery stenosis (stenosis <50%) and thirty gender- and age-matched patients (control group) without coronary artery stenosis according to the coronary angiogram results were prospectively enrolled.

RESULTS

All the patients had no left ventricular regional wall motion abnormality in two-dimensional echocardiography at rest and exercise stress. There was no significant difference in the 16 segmental systolic peak AS at rest between two groups. After exercise stress, the peak systolic AS_rest-stress at mid anterior wall (-7.00%±10.90% vs 2.80%±23.69%) and mid anterolateral wall (-4.40%±18.81% vs 8.80%±19.16%) were decreased, while increased at basal inferolateral wall (14.00%±19.27% vs -5.60%±15.94%) in case group compared with control group (P<.05).

CONCLUSIONS

In patients with mild single vessel coronary artery stenosis, the area strain was decreased at involved segments, while compensatory increased at noninvolved segments after exercise stress. Four-dimensional echocardiography area strain combined with exercise stress echocardiography could sensitively find left ventricular regional systolic function abnormality in patients with mild single vessel coronary artery stenosis, and locate stenosis coronary artery accordingly.

Assessment of left and right ventricular rotational interdependence: A speckle tracking echocardiographic study

OBJECTIVE

We sought to investigate the possible interdependence of the left (LV) and right ventricular (RV) rotational mechanics.

BACKGROUND

Although myocardial fiber architecture and the effect of various pathologic conditions on LV torsional mechanics have already been investigated through multiple studies using different methods, there is still a significant debate about the actual presence and functional significance of RV rotational mechanics.

METHODS

We perform a cross-sectional prospective study of 118 subjects, including 19 normal subjects (NS, 35±7 years), 34 patients with severe aortic stenosis (AS, 44±16 years), 26 patients with nonobstructive hypertrophic cardiomyopathies (HCM, 46±18), and 39 patients with nonischemic dilated cardiomyopathies (DCM, 39±13 years). LV and RV rotational parameters were measured using velocity vector imaging. Total LV and RV apical segment rotations as well as the rotation of the free wall of RV apex were measured separately. Interdependence of the LV and RV rotational mechanics was assessed using the Spearman rho test.

RESULTS

Both LV (7.3°±4.1° in NS, 11°±4.6° in AS, 7.7°±5.2° in HCM, and 1.9°±2° in DCM, P=<.0001) and RV apexes (4.7°±2° in NS, 6.1°±4° in AS, 3.2°±3.7° in HCM, and 2.4°±3.6° in DCM, P=<.0001) rotated counterclockwise in all the four study groups. Interventricular apical rotation interdependence was stronger in the AS (Spearman rho [ρ]: .716; P=.000) and in the HCM (ρ: .395; P=.04) subgroups than in the NS (ρ: .26; P=.27) and DCM (ρ: .215; P=.18). In DCM patients, RV apex rotation appeared to be independent of LV rotation. RV free wall apical rotation was larger than its corresponding value for the total apical segments in all studied groups. This difference was significant only in the AS (P=.007).

CONCLUSION

Our findings demonstrated a close correlation between RV and LV apical rotation parameters in different cardiac conditions as well as in normal subjects. However, in DCM patients, we also showed some independent rotation of the RV from the LV apex.

Predictors of incipient dysfunction of all cardiac chambers after treatment of metastatic renal cell carcinoma by tyrosine kinase inhibitors

PURPOSE

We aimed to explore the hypothesis that early subclinical cardiac chamber dysfunction secondary to tyrosine kinase inhibitors (TKIs) in patients with metastatic renal cell carcinoma could be signaled by abnormal cardiac mechanics demonstrated by velocity vector imaging.

METHODS

Echocardiographic images were acquired from the apical views in 23 metastatic renal cell carcinoma patients. All patients had baseline and at least a 3-month follow-up echocardiogram after receiving TKI therapy. Subendocardial borders of all the cardiac chambers were traced to obtain volumetric and deformation indices.

RESULTS

Mean age was 67 ± 9 years with 92% men. The right ventricle peak systolic global longitudinal strain (GLɛ) and strain rate were significantly lower after TKIs (-23.49 ± 5.1 versus -19.81 ± 5.5, p = 0.002 and -1.52 ± 0.52 versus -1.24 ± 0.35 p = 0.02, respectively). LV GLɛ was not statistically different. Volumetric and deformation indices showed a minimal decrease of the right atrium reservoir and conduit functions, and no significant changes of left atrial function.

CONCLUSIONS

The right heart exhibited greater strain changes than the left heart after TKI treatment. The implications of these findings and their potential significance warrant further work.

Inter-study reproducibility of left ventricular torsion and torsion rate quantification using MR myocardial feature tracking

BACKGROUND

To determine the inter-study reproducibility of MR feature tracking (MR-FT) derived left ventricular (LV) torsion and torsion rates for a combined assessment of systolic and diastolic myocardial function.

METHODS

Steady-state free precession (SSFP) cine LV short-axis stacks were acquired at 9:00 (Exam A), 9:30 (Exam B), and 14:00 (Exam C) in 16 healthy volunteers at 3 Tesla. SSFP images were analyzed offline using MR-FT to assess rotational displacement in apical and basal slices. Global peak torsion, peak systolic and peak diastolic torsion rates were calculated using different definitions ("twist", "normalized twist" and "circumferential-longitudinal (CL) shear angle"). Exam A and B were compared to assess the inter-study reproducibility. Morning and afternoon scans were compared to address possible diurnal variation.

RESULTS

The different methods showed good inter-study reproducibility for global peak torsion (intraclass correlation coefficient [ICC]: 0.90-0.92; coefficient of variation [CoV]: 19.0-20.3%) and global peak systolic torsion rate (ICC: 0.82-0.84; CoV: 25.9-29.0%). Conversely, global peak diastolic torsion rate showed little inter-study reproducibility (ICC: 0.34-0.47; CoV: 40.8-45.5%). Global peak torsion as determined by the CL shear angle showed the best inter-study reproducibility (ICC: 0.90;CoV: 19.0%). MR-FT results were not measurably affected by diurnal variation between morning and afternoon scans (CL shear angle: 4.8 ± 1.4°, 4.8 ± 1.5°, and 4.1 ± 1.6° for Exam A, B, and C, respectively; P = 0.21).

CONCLUSION

MR-FT based derivation of myocardial peak torsion and peak systolic torsion rate has high inter-study reproducibility as opposed to peak diastolic torsion rate. The CL shear angle was the most reproducible parameter independently of cardiac anatomy and may develop into a robust tool to quantify cardiac rotational mechanics in longitudinal MR-FT patient studies.

Subclinical impairment of left ventricular function in diabetic patients with or without obesity: A study based on three-dimensional speckle tracking echocardiography

AIMS

The aim of this study was to investigate subclinical left ventricular (LV) changes between type 2 diabetic patients with or without obesity using three-dimensional speckle-tracking echocardiography (3DSTE).

METHODS

A total of 77 type 2 diabetic patients, including 36 subjects with BMI < 25 kg/m(2) and 41 subjects with BMI ≥ 25 kg/m(2), as well as 40 age- and sex-matched controls (BMI: 18.5 ~ 24.5 kg/m(2)) were studied. Waist circumference was measured in diabetic patients with a BMI ≥ 25 kg/m(2) to determine whether abdominal obesity as a complication was present. Real-time three-dimensional (3D) full volume images of the left ventricle were recorded and analyzed. Left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS) were calculated and compared.

RESULTS

Compared with the controls, diabetic subjects without overall obesity had significantly lower GCS, GAS, and GRS (p < 0.05), as well as markedly lower GLS (p < 0.001). However, 3D-LVEF and all global strains in diabetic subjects with overall obesity were not only markedly lower compared with controls (p  <  0.002 and p < 0.001), but also significantly lower than those in diabetic subjects without overall obesity (p  <  0.002 and p  <  0.05). HbA1c and BMI showed negative impacts on all strains in diabetic patients. Meanwhile, the diabetic subjects with overall and abdominal obesity had significantly reduced GLS, GCS, GAS, and GRS compared with those with overall obesity only (all p  <  0.05).

CONCLUSIONS

Type 2 diabetic patients demonstrated early-stage subclinical LV deformation and dysfunction, whilst coexistent obesity resulted in further damage to myocardial contractility and reduced LVEF. 3DSTE was a sensitive method for detecting these abnormalities.

Does accessory pathway significantly alter left ventricular twist/torsion? A study in Wolff-Parkinson-White syndrome by velocity vector imaging

BACKGROUND

The aim of this study was to determine the impact of manifest accessory pathway on left ventricle (LV) twist physiology in Wolff-Parkinson-White (WPW) patients. Although this issue was addressed in 1 study based on speckle tracking method, there was no comparative study with a different technique. We planned to use velocity vector imaging (VVI) to find out how much an accessory pathway can affect LV twist mechanics.

METHODS

Thirty patients were enrolled regarding inclusion and exclusion criteria. Two serial comprehensive transthoracic echocardiography evaluations were performed before and after radiofrequency catheter ablation (RFCA) within 24 hours. Stored cine loops were analyzed using VVI technique and LV twist and related parameters were extracted.

RESULTS

Comparing pre- and post-RFCA data, no significant changes were observed in LV systolic and diastolic dimensions, LV ejection fraction (LVEF), and Doppler and tissue Doppler-related parameters. VVI study revealed remarkable rise in peak LV apical rotation (10.3º ± 3.0º to 13.8º ± 3.6º, P < 0.001) and basal rotation (-6.0 ± 1.8º to -7.7 ± 1.8º, P < 0.001) after RFCA. Subsequently LV twist showed a surge from 14.7º ± 3.9º to 20.2º ± 4.4º (P < 0.001). LV untwisting rate changed significantly from -96 ± 67 to -149.0 ± 47.5°/sec (P < 0.001) and apical-basal rotation delay showed a remarkable decline after RFCA (106 ± 81 vs. 42.8 ± 26.0 msec, P < 0.001).

CONCLUSION

Accessory pathways have a major impact on LV twist mechanics.

Impact of diet and exercise training-induced weight loss on myocardial mechanics in severely obese adolescents

OBJECTIVE

Recent findings indicated silent incipient myocardial dysfunction in juvenile obesity despite normal global cardiac function. The present study investigated whether lifestyle intervention is able to favorably impact these obesity-related myocardial abnormalities and whether improvements are related to changes in insulin resistance and cardiac remodeling.

DESIGN AND METHODS

Twenty-eight severe obese adolescents (OB) participated in a 9 month lifestyle intervention program (LIP) based on aerobic exercise and diet. Twenty healthy adolescents (CG) served as controls. Conventional echocardiography and myocardial mechanics were obtained at baseline and follow-up along with insulin resistance.

RESULTS

Insulin sensitivity improved (P < 0.001) and body weight decreased (P < 0.001) consecutive to LIP. At baseline, OB had depressed longitudinal (L) strain (CG: -18.3 ± 2.6, OB: -14.2 ± 3.6%, P < 0.001) and enhanced twist compared to controls. The LIP in OB restored L strain to normal values (-16.9 ± 3.5%, NS), whereas it did not affect twist mechanics. From stepwise multiple regression analysis, only baseline L strain and changes in BMI Z-score (r(2) -adjusted = 0.49, P < 0.001) emerged as independent predictors of L strain changes.

CONCLUSIONS

Juvenile obesity is associated with myocardial mechanic abnormalities that can be partly corrected by lifestyle intervention. Restoration of longitudinal myocardial function occurs in the absence of left ventricular remodeling changes and is not associated with insulin resistance improvements.

Worsening left ventricular apical peak strain early after right ventricular pacing

We aimed to determine the effect of short-term right ventricle pacing (RV) on left ventricle (LV) mechanics using speckle tracking analysis. Conventional echocardiography and two-dimensional strain imaging was studied in 38 patients, mean age 81.6 ± 7.0, that had undergone pacemaker placement and were greater than 90% ventricularly paced. Mean duration of 24 months of RV pacing resulted in a significant decline in: LV apical diastolic rotational velocities (-59.0 ± -38.9 °/s to -28.0 ± -11.5 °/s, p 0.02), peak strain in the LV apical septal wall (-15.6 ± 8.5 to -13.5 ± 7.6, p 0.02), peak strain in LV apical lateral wall (-13.4 ± 8.9 to -11.4 ± 7.3, p 0.02). Thus, with only 24 months of RV pacing, there was a significant decline in peak strain of the LV apex and in apical diastolic rotational velocity that could account for eventual decline in left ventricular function.

Two-dimensional strain and twist by vector velocity imaging in adolescents with severe obesity

The prevalence of severe obesity is increasing worldwide in adolescents. Whether it is associated with functional myocardial abnormalities remains largely unknown, potentially because of its frequent association with other cardiovascular risk factors and also use of insensitive techniques to detect subclinical changes in myocardial function. We used 2D vector velocity imaging (VVI) to investigate early changes in left ventricular (LV) myocardial function in youths with isolated severe obesity. Thirty-seven asymptomatic severely obese adolescents free of diabetes and hypertension, and 24 lean controls were enrolled. LV longitudinal, basal, and apical circumferential strain, strain rate (SR), rotations, and LV twist were measured. Obese adolescents had greater LV mass and reduced systolic and early diastolic tissue Doppler imaging (TDI) velocities than lean counterparts. L strain (-24%) and systolic and early diastolic SR were also diminished in the obese, whereas no intergroup differences existed for the circumferential deformation indexes. LV twist was more pronounced in the obese (+1.7°, P < 0.01) on account of greater apical rotation only (4.1 ± 0.9 vs. 5.2 ± 1.2°, P < 0.01), potentially compensating for the loss in longitudinal function. Systolic-diastolic coupling, an important component of early filling and diastolic function, was maintained with severe obesity. No intergroup differences were reported regarding time to peak values for all VVI indexes highlighting that dynamics of strain and twist/untwist along the cardiac cycle was preserved with severe obesity. Isolated severe obesity in adolescents, at a preclinical stage, is associated with changes in myocardial deformation and torsional mechanics that could be in part related to alterations in relaxation and contractility properties of subendocardial fibers.