The importance of frontal QRS-T angle for predicting non-dipper status in hypertensive patients without left ventricular hypertrophy

Background: Frontal QRS-T angle is a novel marker of myocardial repolarization, and an increased frontal QRS-T angle associated with adverse cardiac outcomes. Non-dipper hypertension is also associated with adverse cardiac outcomes. This study aimed to investigate the relationship between frontal QRS-T angle and non-dipper status in hypertensive patients without left ventricular hypertrophy (LVH).

Methods: This study included 122 hypertensive patients without LVH. Patients were divided into two groups: dipper hypertension and non-dipper hypertension. The frontal QRS-T angle was calculated from 12-lead electrocardiography.

Results: Frontal QRS-T angle (47.9° ± 29.7° vs. 26.7° ± 19.6°, P < 0.001) was significantly higher in patients with non-dipper hypertension than in patients with dipper hypertension. In addition, frontal QRS-T angle was positively correlated with sleeping systolic (r = 0.211, P = 0.020), and diastolic (r = 0.199, P = 0.028) blood pressures (BP), even if they were weak. Multivariate analysis showed that the frontal QRS-T angle was independent predictor of non-dipper status (QR: 1.037, 95% CI: 1.019–1.056, P < 0.001).

Conclusion: Frontal QRS-T angle is independent predictor of non-dipper status in hypertensive patients without LVH.     

Determination of left ventricular mass by real-time three-dimensional echocardiography: in vitro validation

Twenty-one explanted fixed hearts (14 dogs and 7 pigs) were examined to validate newly developed real-time three-dimensional (RT3D) echocardiography for measurement of left ventricular (LV) mass in vitro and to compare its accuracy and variability with those of conventional echocardiographic measurements. There was an excellent correlation and high degree of agreement for the determination of LV mass between RT3D echocardiography and true mass measurement (r = 0.98; standard error of the estimate [SEE] = 7.3 g; absolute difference [AD] = 2.8 g; y = 1.00 x -4.0, interobserver variability; 5.0%). The conventional echocardiographic methods yielded weaker correlations, larger standard errors, and interobserver variability (area-length method: r = 0.90; SEE = 13.3 g; AD = 13.2 g; 13.3 % / truncated ellipsoid method: r = 0.91; SEE = 14.7 g; AD = 10.5 g; 7. 9% / M-mode: r = 0.91; SEE = 16.2 g; AD = 9.4 g; 15.3%). Determination of LV mass by RT3D echocardiography has a high degree of accuracy and is superior to conventional one- and two-dimensional echocardiographic methods.     

Left atrial abnormality by electrocardiogram predicts left ventricular hypertrophy by echocardiography in the presence of right bundle-branch block

Background: Left ventricular hypertrophy (LVH) on the electrocardiogram (ECG) may be masked in the presence of complete right bundle-branch block (RBBB). Left bundle-branch block on the ECG is associated with LVH at autopsy in 93% of hearts studied. However, RBBB does not predict LVH and the usual ECG criteria applied for LVH may not be reliable in the presence of RBBB. Hypothesis: The study was undertaken to evaluate left atrial (LA) abnormality as a criterion for the diagnosis of LVH in the presence of RBBB. Methods: Left atrial abnormality in the ECG was assessed by two independent observers as a criterion of LVH in the presence of RBBB in 100 patients, and data were compared with those of 50 patients without LA abnormality. Results: Left ventricular hypertrophy was confirmed by echocardiographic determination of left ventricular (LV) mass in both groups. Observers reliably differentiated between hy-pertrophied and normal-sized LV in the presence of RBBB by using LA abnormality as an ECG criterion when correlated with LV mass determined by echocardiography. Observer 1 correctly detected LVH in 88% and Observer 2 in 82% of patients. False positive diagnosis was made in 12 and 18% of patients by Observers 1 and 2, respectively. Observers' performance of recognition of LA abnormality in the present study was 94%. Results showed sensitivity of 76 and 70% and specificity of 84 and 92% for Observers 1 and 2, respectively. Left ventricular mass increased significantly and was diagnostic of LVH in 92% of patients with LA abnormality. Left ventricular mass was high in 84% of patients when corrected by body surface area. LVH in the presence of RBBB by the ECG was found in only seven patients (5%) when six commonly used conventional criteria of diagnosis of LVH by ECG were employed. Regression analysis found LA abnormality to be a strong independent predictor of increased LV mass. Multiple regression analysis revealed that age, body mass index, body surface area, and frontal axis are also significant predictors of LV mass. Conclusion: The results obtained by the correlation of LA abnormality by ECG and LVH by echocardiography conclude that LA abnormality by ECG was significantly diagnostic of LV hypertrophy in the presence of RBBB.     

Value of two-dimensional speckle tracking and real time three-dimensional echocardiography for the identification of subclinical left ventricular dysfunction in patients referred for routine echocardiography

Background: While speckle tracking echocardiography (2DSTE) can be used to study longitudinal, circumferential, and radial function, real time 3D echocardiography (3DE) generates dynamic time–volume curves, offering a wide array of new parameters for characterizing mechanical and volumetric properties of the left ventricle (LV). Our aim was to investigate the merit of these new techniques to separate normal from abnormal echocardiograms as well as to identify subclinical disease in reportedly normal subjects. Methods: Eighty‐one patients (mean age 61 ± 16 years) underwent standard 2D echocardiography (2DE) enhanced by 2DSTE and 3DE. The data included LV volumes and ejection fraction (EF), velocities, strain/strain rate, and peak ejection/filling rates. The patients were divided into Group 1: normal (n = 42) and Group 2: abnormal (n = 39) on the basis of an expert interpretation of the resting 2DE. Results: Global longitudinal strain (%) was 17 ± 4 in Group1 and 14 ± 4 in Group2 (P < 0.002). Strain rates (SR, 1/sec) at peak systole (1.1 ± 0.2 vs 0.9 ± 0.3, P < 0.001) and early diastole (1.3 ± 0.3 vs 0.9 ± 0.3, P < 0.001) were also higher in Group1. Three‐dimensional peak ejection and filling rates (EDV/sec) were significantly higher in Group1 (?2.5 ± 0.4 vs ?2.1 ± 0.7, and 1.8 ± 0.2 vs 1.5 ± 0.5, P < 0.002, P < 0.001, respectively). The best discriminatory power for predicting a normal 2DE was systolic SR with a sensitivity of 82% and a specificity of 54% using a cutoff value of 1.09. Interestingly, 19/41 (46%) of Group1 patients had systolic SR < 1.09, suggesting subclinical disease. Conclusions: 2DSTE and 3DE can discriminate between normal and abnormal echocardiograms and have the potential to detect subclinical LV dysfunction. (Echocardiography 2012;29:588‐597)     

左室舒张性心功能障碍超声左心形态、功能及运动耐量的改变50例分析

对核素心血池扫描证实的５０例左室舒张性心功能障碍（ＬＶＤＤ）病例、２６例左室收缩性心功能障碍（ＬＶＳＨＦ）病例进行Ｍ型、二维、多普勒超声心动图及活动平板运动试验检测，并以２０例正常人为对照组（ＣＧ）。结果表明：（１）左心形态学改变：与ＬＶＳＨＦ组比较，ＬＶＤＤ组左房内径（ＬＡＤ）、左室内径（ＬＶＤ）无明显增加，室间隔厚度（ＩＶＳＴ）、左室后壁厚度（ＰＷＴ）增加。与ＣＧ组比较，ＬＶＤＤ组ＬＡＤ、ＩＶＳＴ、ＰＷＴ增加，但ＬＶＤ差异无显著性。（２）ＬＶＤＤ组收缩功能指标：左室射血分数（ＬＶＥＦ）、心脏指数（ＣＩ）与ＣＧ组比较差异无显著性，ＬＶＳＨＦ组与ＣＧ组比较，ＬＶＳＨＦ组ＬＶＥＦ、ＣＩ减低。与ＣＧ组比较，ＬＶＤＤ组左室舒张功能指标：二尖瓣舒张早期流速峰值（ＥＰＦＶ）、二尖瓣舒张早、晚期流速峰值比（Ｅ／Ａ）、舒张早期减速度（ＤＣ）比ＣＧ组减低，二尖瓣舒张晚期流速峰值（ＡＰＦＶ）、等容舒张时间（ＩＲＴ）较ＣＧ组增高。ＬＶＤＤ组各左室舒张功能指标与ＬＶＳＨＦ组差异无显著性。（３）ＬＶＤＤ组运动时间、运动当量显著低于ＣＧ组，但高于ＬＶＳＨＦ组。     

M-mode echocardiography overestimates left ventricular mass in patients with normal left ventricular shape: a comparative study using three-dimensional echocardiography.

AIMS: We sought to evaluate whether left ventricular (LV) mass (M) determined by M-mode echocardiography is overestimated compared with LVM calculated by three-dimensional (3D) echocardiography (E) in patients with normal LV shape. METHODS AND RESULTS: A total of 112 studies in 56 patients (60+/-13 years) with hypertension (n=25) or aortic stenosis (n=31) and 30 control subjects (57+/-14 years) evaluated for cardiac sources of embolism were analyzed. LVM by M-mode and 3DE was highly correlated (r=0.85; p<0.001). However, there were broad limits of agreement (-58 to 110 g) demonstrating large variability between the methods. M-mode overestimated 3DE LVM by a mean of 15+/-24% (p<0.001) with overestimation in controls and the different patient groups. Variability was unrelated to increasing quartiles of LVM values. Using technique-specific partition values for normal LVM, the agreement between M-mode and 3DE for the detection of LV hypertrophy was 83% (Kappa=0.59; p<0.001). CONCLUSION: Although M-mode and 3DE correlate well for the calculation of LVM, there is a systematic difference between the two techniques leading to overestimation of LVM by the 1D technique. Thus, previously published cutoff values for normal LVM derived from M-mode may not apply for 3DE. However, the use of technique-specific partition values allows stratification of patients for the presence of LV hypertrophy with reasonable agreement.     

Comparison of two- and three-dimensional transthoracic echocardiography in the assessment of trabeculations and trabecular mass in left ventricular noncompaction

Twenty-one patients (mean age 47.5 years, 9 females) with left ventricular noncompaction (LVNC) diagnosed by both two-dimensional transthoracic echocardiography (2DTTE) and live/real time three-dimensional transthoracic echocardiography (3DTTE) were included in the study. Left ventricular (LV) mass was calculated with epicardial and endocardial border tracings first including the LV trabeculations and then excluding them. LV trabecular mass was then derived as the difference between the two measurements. This was done by 2DTTE using the modified biplane Simpson's method and by live/real time 3DTTE using the Tom Tec imaging system. The number of trabeculations arising from each segment of LV walls as well as the segmental distribution of trabeculations were also assessed by both 2DTTE and 3DTTE. The calculated LV trabecular mass by 3DTTE (mean 11.8 +/- 5.5 g) was significantly greater than 2DTTE (mean 7.3 +/- 4.3 g, P = 0.005). The total number of trabeculations assessed by 3DTTE (mean 11.2 +/- 3.3) was also significantly greater than 2DTTE (mean 3.76 +/- 1.2, P < 0.0001). The values for inter- and intraobserver variability were lower for 3DTTE than 2DTTE. In conclusion, both LV trabecular mass as well as the total number of trabeculations in patients with LVNC were significantly underestimated by 2DTTE as compared to 3DTTE.     

Differentiation of left ventricular diastolic dysfunction, identification of pseudonormal/restrictive mitral inflow pattern and determination of left ventricular filling pressure by Tei index obtained from tissue Doppler echocardiography

BACKGROUND: Tei index obtained from tissue Doppler echocardiography (TDE-Tei index) has an inherent advantage of recording its systolic and diastolic components simultaneously on the same cardiac cycle. The aims of this study are to evaluate whether TDE-Tei index also exerts a correlation with left ventricular (LV) systolic and diastolic function and filling pressure and to see whether it can effectively identify the pseudonormal/restrictive mitral filling pattern. METHODS: Echocardiographic examination was performed in 243 consecutive patients. These patients were classified into three groups as normal, abnormal relaxation, and pseudonormal/restrictive groups according to the transmitral E/A-wave velocity (E/A), early diastolic velocity of lateral mitral annulus (Ea) and E/Ea. RESULTS: Standard Doppler indices of LV filling such as E, A, E/A, and E-wave deceleration time had a bimodal distribution, but Ea decreased and E/Ea and TDE-Tei index increased progressively with worsening of LV diastolic function. The sensitivity and specificity of TDE-Tei index>0.51 in the discrimination of pseudonormal/restrictive filling pattern were 85% and 96%, respectively. After stepwise multiple linear regression analysis, TDE-Tei index had a significant negative correlation with Ea (beta=-0.296, P<0.001) and ejection fraction (beta=-0.293, P<0.001) and positive correlation with E/Ea (beta=0.235, P=0.001). CONCLUSIONS: TDE-Tei index increased with worsening of LV diastolic function and can effectively identify the pseudonormal/restrictive mitral inflow pattern. It also correlated with the echocardiographic parameters of LV systolic and diastolic function and filling pressure. It suggests that TDE-Tei index is a simple and feasible marker in assessing global LV function.     

超声心动图观察健康人舒张功能减退与左房增大的相关性及临床意义

目的探讨健康人生理性舒张功能减退与左房增大的相关性及临床意义.方法应用超声心动图方法观察4575例年龄20～97岁健康人的心脏结构、血流及功能,其中男性2150例,女性2425例,取胸骨旁左室长轴切面测量左房、左室,计算左室射血分数.应用多普勒超声心动图测量二尖瓣舒张早期血流峰值速度（EPFV）及心房收缩期血流峰值速度（APFV）.以10岁为一年龄段分为7个年龄组,观察各年龄段心脏结构及心功能是否存在差异.同时观察年龄与心脏结构及心功能的相关性.结果各年龄段左室内径、左室射血分数无统计学差异.随年龄段增加,左房增大,EPFV减慢,APFV增快,E/A比值减小,除80年龄组外,左房内径、EPFV及APFV各年龄段均有统计学差异（均P＜0.05）.年龄与EPFV及E/A比值呈显著负相关,与左房内径、APFV呈显著正相关;左房内径与EPFV及E/A比值呈显著负相关,与APFV呈显著正相关（均P＜0.01）.结论随年龄增长,左房增大,左室舒张功能减退,而左室内径及左室收缩功能无明显变化.左房内径与左室舒张充盈的各项指标具有良好的相关性,提示左房增大可能是左室舒张功能减退的重要表现之一.     

Influence of the vectorcardiogram synthesis matrix on the power of the electrocardiogram-derived spatial QRS-T angle to predict arrhythmias in patients with ischemic heart disease and systolic left ventricular dysfunction

Background and Purpose

Several studies have demonstrated that the spatial mean QRS-T angle (SA) predicts cardiac events and mortality. Spatial mean QRS-T angle is a vectorcardiographic variable. Because in clinical practice, 12-lead standard electrocardiograms (ECGs) are recorded rather than vectorcardiograms (VCGs) according to Frank, VCGs are commonly obtained by synthesizing them from 12-lead ECGs, by using a VCG synthesis matrix. Hence, the thus computed SA is an estimate of the real SA measured in the Frank VCG. Recent studies have shown that Kors VCG synthesis matrix yields better estimates of SA than the inverse Dower VCG synthesis matrix. Our current study aims to compare the predictive power of these SA variants for the occurrence of potentially lethal arrhythmias.

Methods

The study group consisted of patients with ischemic heart disease and left ventricular systolic dysfunction who received an implantable cardioverter-defibrillator (ICD) for primary prevention. During follow-up, the occurrence of appropriate device therapy (occurrence of ventricular arrhythmia) was noted. Alternative SAs were computed in VCGs synthesized from standard 12-lead ECGs by using either the inverse Dower matrix (SA-Dower) or the Kors matrix (SA-Kors). Comparison of the predictive power of SA-Dower and SA- Kors was performed by receiver operating characteristic analysis, by Kaplan-Meier analysis, and by univariate and multivariate Cox regression analysis, using every 10th percentile of SA as a cutoff value.

Results

The study group consisted of 412 patients (361 men; mean ± SD age 63 ± 11 years), in which 56 patients had appropriate ICD therapy during follow-up. Receiver operating characteristic analysis revealed that the area under the curve of SA-Kors was significantly larger than area under the curve of SA-Dower (0.646 vs 0.607, P = .043). The discriminative power of SA-Kors for the absence/presence of appropriate ICD therapy in patients during follow-up was generally superior to SA-Dower over a wide range of cutoff values in the Kaplan-Meier analysis and generally yielded stronger hazard ratios in the univariate and multivariate Cox regression analyses.

Conclusion

If there is no specific reason to use the inverse Dower matrix, VCG synthesis from standard 12-lead ECGs should preferably be done by using the Kors matrix. It is likely to assume that already published studies in which the predictive value of SA-Dower was demonstrated would yield stronger results if the SA-Dower angles were substituted by SA-Kors angles.     

Physiologic determinants of left ventricular systolic torsion assessed by speckle tracking echocardiography in healthy subjects

Background: The associations of left ventricular (LV) systolic torsion with clinical and echocardiographic variables in physiological conditions have not been fully investigated. We explored the independent determinants of LV systolic torsion in a population of normal subjects. Methods: In 119 healthy subjects, peak twist angle (LVtw) and torsion (LVtor) during ejection, and the QRS‐LVtw interval (time‐to‐peak LVtw) were measured by speckle tracking. LV twisting rate and rotational deformation delay were also determined. Results: Stepwise multiple regression showed that LVtw was independently associated with indexed end‐systolic volume (β=–0.200, P < 0.0001), peak early diastolic mitral annulus velocity (β=–0.186, P = 0.0001), heart rate (β= 0.178, P = 0.0003), and male gender (β=–0.174, P = 0.0004). Similar results were found for LVtor. Age was the only parameter, which has demonstrated an independent correlation with time‐to‐peak LVtw (β= 0.329, P < 0.0001). Despite significance of these associations, the proportions of variability explained by regression models were relatively low (range 11–26%), and no accurate predictive models were identifiable for LV twisting rate and rotational deformation delay. Conclusion: In normal individuals, indexed end‐systolic LV volume, LV relaxation, heart rate, gender, and age correlate independently with LV torsion mechanics. However, conventional echocardiographic and clinical variables are not able to predict LV torsion mechanics. (Echocardiography 2011;28:641‐648)     

Quantitative assessment of left ventricular volume and ejection fraction using two-dimensional speckle tracking echocardiography

Aims: Two-dimensional speckle tracking echocardiography (2DSTE) allowsmeasurements of left ventricular (LV) volumes and LV ejectionfraction (LVEF) without manual tracings. Our goal was to determinethe accuracy of 2DSTE against real-time 3D echocardiography(RT3DE) and against cardiac magnetic resonance (CMR) imaging. Methods and results: In Protocol 1, 2DSTE data in the apical four-chamber view (iE33,Philips) and CMR images (Philips 1.5T scanner) were obtainedin 20 patients. The 2DSTE data were analysed using custom software,which automatically performed speckle tracking analysis throughoutthe cardiac cycle. LV volume curves were generated using thesingle-plane Simpson's formula, from which end-diastolic volume(LVEDV), end-systolic volume (LVESV), and LVEF were calculated.In Protocol 2, the 2DSTE and RT3DE data were acquired in 181subjects. RT3DE data sets were acquired, and LV volumes andLVEF were measured using QLab software (Philips). In Protocol1, excellent correlations were noted between the methods forLVEDV (r = 0.95), ESV (r = 0.95), and LVEF (r = 0.88). In Protocol2, LV volume waveforms suitable for analysis were obtained from2DSTE images in all subjects. The time required for analysiswas <2 min per patient. Excellent correlations were notedbetween the methods for LVEDV (r = 0.95), ESV (r = 0.97), andLVEF (r = 0.92). However, 2DSTE significantly underestimatedLVEDV, resulting in a mean of 8% underestimation in LVEF. Intra-and inter-observer variabilities of 2DSTE were 7 and 9% in LVvolume and 6 and 8% in LVEF, respectively. Conclusions: Two-dimensional speckle tracking echocardiography measurementsresulted in a small but significant underestimation of LVEDVand EF compared with RT3DE. However, the accuracy, low intra-and inter-observer variabilities and speed of analysis make2DSTE a potentially useful modality for LV functional assessmentin the routine clinical setting.     

Impact of body mass index on markers of left ventricular thickness and mass calculation: results of a pilot analysis

Specific correlations between body mass index (BMI) and left ventricular (LV) thickness have been conflicting. Accordingly, we investigated if a particular correlation exists between BMI and echocardiographic markers of ventricular function. METHODS: A total of 122 patients, referred for routine transthoracic echocardiography, were included in this prospective pilot study using a 3:1 randomization approach. Patient demographics were obtained using a questionnaire. RESULTS: Group I consisted of 80 obese (BMI was >30 kg/m2), Group II of 16 overweight (BMI between 26 and 29 kg/m2), and Group III of 26 normal BMI (BMI < 25 kg/m2) individuals. No difference was found in left ventricular wall thickness, LV end-systolic cavity dimension, fractional shortening (FS), or pulmonary artery systolic pressure (PASP) among the groups. However, mean LV end-diastolic cavity dimension was greater in Group I (5.0 +/- 0.9 cm) than Group II (4.6 +/- 0.8 cm) or Group III (4.4 +/- 0.9 cm; P < 0.006). LV mass indexed to height(2.7) was also significantly larger in Group I (61 +/- 21) when compared to Group III (48 +/- 19; P < 0.001). Finally, left atrial diameter (4.3 +/- 0.7 cm) was also larger (3.8 +/- 0.6 and 3.6 +/- 0.7, respectively; P < 0.00001). DISCUSSION: We found no correlation between BMI and LV wall thickness, FS, or PASP despite the high prevalence of diabetes and hypertension in obese individuals. However, obese individuals had an increased LV end-diastolic cavity dimension, LV mass/height(2.7), and left atrial diameter. These findings could represent early markers in the sequence of cardiac events occurring with obesity. A larger prospective study is needed to further define the sequence of cardiac abnormalities occurring with increasing BMI.     

Assessment of left ventricular diastolic function by three-dimensional transthoracic echocardiography

Doppler echocardiography assessment of left ventricular (LV) filling pressures at rest and during exercise is the most widely used imaging technique to assess LV diastolic function in clinical practice. However, a sizable number of patients evaluated for suspected LV diastolic function show an inconsistency between the various parameters included in the flowchart recommended by current Doppler echocardiography guidelines and results in an undetermined LV diastolic function. Current three-dimensional echocardiography technology allows obtaining accurate measurements of the left atrial volumes and functions that have been shown to improve the diagnostic accuracy and prognostic value of the algorithms recommended for assessing both LV diastolic dysfunction and heart failure with preserved ejection fraction. Moreover, current software packages used to quantify LV size and function provide also volume-time curves showing the dynamic LV volume change throughout the cardiac cycle. Examining the diastolic part of these curves allows the measurement of several indices of LV filling that have been reported to be useful to differentiate patients with normal LV diastolic function from patients with different degrees of diastolic dysfunction. Finally, several software packages allow to obtain also myocardial deformation parameters from the three-dimensional datasets of both the left atrium and the LV providing additional functional parameters that may be useful to improve the diagnostic yield of three-dimensional echocardiography for the LV diastolic dysfunction. This review summarizes the current applications of three-dimensional echocardiography to assess LV diastolic function.