Study of Left Ventricular Rotation and Torsion in the Acute Phase of ST-Elevation Myocardial Infarction by Speckle Tracking Echocardiography

Background: The mechanics of the complex left ventricular (LV) myocardial fiber architecture may accurately be assessed by speckle tracking echocardiography (STE). The role of STE to assess LV mechanical dysfunction in the setting of ST segment elevation myocardial infarction (AMI) is still poorly studied. Patients and Methods: 29 consecutive patients (55 ± 13 years) presenting with AMI underwent STE within 72 hours of admission. Reperfusion was achieved with thrombolysis in 15 patients and with primary percutaneous coronary intervention in 14. LV rotational and torsion data were registered during peak systole. Standard Doppler data included LV ejection fraction (EF), mitral inflow deceleration time (DT), and conventional E/A ratio. E/E' ratio (mitral inflow E velocity/tissue Doppler E velocity) was calculated as a marker of LV filling pressure. Twelve subjects with clinically indicated but negative dobutamine stress echocardiogram served as Controls. Results: Peak systolic torsion was not only significantly lower in AMI compared with Controls (13.3 ± 7.6 vs. 21.8 ± 6.1; P < 0.01), it was also lower in subjects with LVEF <40% (5.0 ± 2.9) compared with those who had LVEF >40% (10.6 ± 6.6; P < 0.02). Torsion had a modest but significantly positive linear relation (R = 0.6; P < 0.05) with DT, not with E/E' or LVEF. Conclusion: LV systolic torsion is decreased in AMI and more markedly decreased in patients with LVEF <40%. The most significant linear relationship between DT and torsion may possibly indicate that the LV mechanical dysfunction is also associated with altered filling dynamics. (Echocardiography 2010;27:45-49)     

Chronic Effect of Right Ventricular Pacing on Left Ventricular Rotational Synchrony in Patients with Complete Atrioventricular Block

Background: Chronic effect of right ventricular (RV) pacing on left ventricular (LV) rotational synchrony is unknown. The aim of this study is to assess chronic effect of RV pacing on LV rotational synchrony using two‐dimensional ultrasound speckle tracking imaging. Methods and Results: Thirty‐one patients who underwent dual‐chamber pacemaker implantation for complete atrioventricular block, and age‐ and sex‐matched 10 healthy controls were assessed. We divided our patients into RV apical (RVA, n = 16) and RV outflow tract (RVOT, n = 15) pacing groups. We compared echocardiographic parameters such as LV rotational synchrony between pacing groups and healthy control. We defined Q to peak rotation interval as the interval from the beginning of the Q‐wave to the peak apical counter‐clockwise or peak basal clockwise rotation. We calculated apical–basal rotation delay by subtracting basal Q to peak rotation interval from apical one as the representative of rotational synchronization. Apical–basal rotation delay of RVA pacing was significantly longer than that of healthy control (100 ± 110 vs. ?6 ± 15 ms, P = 0.002), while there was no statistically significant difference between RVOT pacing and healthy control (?3 ± 99 vs. ?6 ± 15 ms, P = 0.919). Conclusions: LV rotation during RVOT pacing is synchronous at 15 months after pacemaker implantation, while RVA pacing provokes LV rotational dyssynchrony by inducing delayed apical rotation at 7 years after pacemaker implantation in patients with complete atrioventricular block. (Echocardiography 2011;28:69‐75)     

右室流出道间隔部与心尖部起搏对心功能的影响

目的了解右室流出道间隔部起搏和右室心尖部起搏参数的差异及对心功能的影响。方法65例安装DDD起搏器的患者随机分为右室心尖部（RVA）与右室流出道间隔部（RVS）起搏进行置入时及术后3个月起搏参数、左室射血分数的分析。结果两组基线资料无显著差异，术后15min及3个月两组的起搏阂值、感知、阻抗均无差异，术后3个月右室流出道间隔部组左室射血分数显著高于右室心尖部组（0．57±0．04vs0．50±0．03，p〈0．05）。结论右室流出道间隔部起搏安全可行，且对心功能的影响优于右室心尖部起搏。     

Differences in Left Ventricular Twist Related to Age: Speckle Tracking Echocardiographic Data for Healthy Volunteers from Neonate to Age 70 Years

Objective: To determine normal left ventricular (LV) twist characteristics in different age groups and assess changes between neonates and the elderly. Methods: Short‐axis left ventricle images at basal and apical levels were acquired in 274 healthy volunteers (aged 15 days to 72 years) by two‐dimensional echocardiography, and were analyzed off‐line using Speckle tracking echocardiography (STE) software to obtain LV twist measurements. The peak apical rotation (PAr), peak basal rotation (PBr), peak LV twist (Ptw), peak LV twist normalized by LV length (Ptw N ), peak untwisting velocity (PutwV), and isovolumic untwisting% (Iutw%) were measured. Results: LV twist values vary with age. Ptw was higher in older volunteers. PtwN varied inconsistently with age. PutwV and Iutw% were lower in the young and old with a peak in mid–age ranges. Conclusions: STE is an effective noninvasive method to assess LV twist. Age‐related differences in LV twist may reflect maturation and adaptive modulation of LV torsional biomechanics from neonate to the elderly. (Echocardiography 2010;27:1205‐1210)     

Strain value in the assessment of left ventricular function and prediction of heart failure markers in aortic regurgitation

Background: This study aimed to examine the relationship between biochemical heart failure markers and conventional left ventricular (LV) measurements and strain assessed by speckle‐tracking echocardiography in chronic aortic regurgitation (AR) patients. Methods and Results: LV strain, rotation assessed by speckle‐tracking echocardiography, LV measurements, mitral annular plane excursion measured by M‐mode, and systolic annular plane velocity measured by tissue Doppler echocardiography were analyzed in 64 controls and 65 chronic AR patients. Reduced LV longitudinal strain with increased apical rotation was seen in normal plasma NT‐proBNP patients. Increased NT‐proBNP (>400 pg/mL) was associated with reduced longitudinal and circumferential strain, diminished mitral annular plane excursions and systolic annular plane velocity. Global systolic longitudinal strain was an indepentent predictor of NT‐proBNP level. Longitudinal strain less than 16.0% was the cutoff value for NT‐proBNP >400 pg/mL (P < 0.05). Conclusions: LV strain analysis in conjunction with NT‐proBNP evaluation is a useful tool in assessing LV function in AR patients. (Echocardiography 2011;28:983‐992)     

A theoretical and experimental model of ventricular interdependence

Summary Because of the close anatomical association between the ventricles, the volume of one ventricle can directly affect the volume and pressure within the other ventricle. To study the mechanical coupling between the ventricles, we modeled the right and left ventricles as a two-compartment model with right wall (C_iw), septal (C_s), and left wall (C_lw) compliances. Based on the balances of forces across the septum, four equations were obtained to predict the transfer of pressure (P) and volume (V) information from one ventricle to another. The validity of the theoretical analysis was tested first in a physical model and then in a post-mortem heart preparation. The standard errors of estimate comparing the predicted to measured values were low for both the physical model and the post-mortem heart data. All values were significantly related (P<0.05) with r>0.89. The results show excellent correlation between predicted and measured values. This model provides a better understanding of ventricular interdependence and may help to predict effects of hypertrophy and/or myocardial ischemia on ventricular interdependence.This study was supported in part by PHS NIH Grant Nos. HL31644 and HL22843. Dr. Santamore is a recipient of an NIH Research Carrer Development Award No. H101026     

Four left ventricular apical abnormalities

This editorial reviews the clinical presentation, electrocardiographic manifestations, appearance of the left ventricle by imaging techniques, and the state of the coronary arteries in four left ventricular apical abnormalities (Table I). Three of these conditions, namely, noncompaction, apical hypertrophy, and left ventricle aneurysm, can be somewhat malignant. The fourth condition--tako-tsubo--is generally benign. Treatment depends on the clinical condition of the patient.     

斑点追踪显像评价左室旋转运动的研究进展

心动周期中心尖及心底沿左室长轴向不同方向旋转,引起心脏扭曲或扭转运动。心肌纤维的螺旋状排列是联系心脏旋转运动解剖学与生理学机制的基础。斑点追踪显像可检测心脏扭转运动,对预测及治疗心肌功能障碍提供有价值的信息,是评价心脏旋转运动的新超声心动图技术。