Assessment of the left ventricular function with the Nuclear Stethoscope

The evaluation of the left ventricular function with the Nuclear Stethoscope was performed on 27 patients with heart diseases. The reproducibility of the measurements was good. Repetitions of EF, ER and EDV estimations yielded errors of 2.63%, 1.45% and 0.31%, respectively. The comparison with the results of camera ventriculography showed a good agreement of EF, contraction velocity parameters and relaxation velocity parameters, with a cor. coeff. of greater or equal to 0.750. An especially high correlation was found between the NS EF and NS ER (r=0.968). It was concluded that the Nuclear Stethoscope provides a reliable evaluation of left ventricular function.Fellow of the Alexander von Humboldt Foundation     

Errors in the determination of left ventricular functional parameters

Gated blood-pool scans of the left ventricle are routinely employed for determination of the left ventricular ejection fraction. Recently, attempts have been made to evaluate other left ventricular functional parameters. These values include peak emptying rate (PER), time to peak emptying rate (TPER), peak filling rate (PFR), and time to peak filling rate (TPFR). In studying these parameters clinically, we identified many software errors and assumptions that impact on these values. These errors may also affect the determination of left ventricular ejection fraction (EF). We conclude that before any serious investigation of left ventricular functional parameters is undertaken, a detailed evaluation and standardization of the acquisition and edge detection algorithms must be performed.     

Evaluation of left atrial contraction contribution to left ventricular filling using cardiovascular magnetic resonance

Purpose:

To describe a new method to quantify the left atrial contraction contribution (ACC) to left ventricular (LV) filling using cardiovascular magnetic resonance (CMR).

Materials and Methods:

We assessed 120 normal subjects (50% female) using steady‐state free precession CMR volumetry. Volumes measurements were performed using short axis and rotational long axis views. The percentage of ACC was calculated by dividing the LV filling volume resulting from left atrial (LA) contraction by the LV stroke volume (LVSV).

Results:

The described method was well reproducible. The ACC in normal subjects was 15 ± 5% for ages <40 years, 28 ± 8% for ages 40 to 55 years, and 38 ± 5% for ages >55 years. When adjusted for age, ie, dividing the ACC percentage by age, a value between 0.4 and 0.7 was found to represent the normal range of ACC at any age.

Conclusion:

The study presents a new and accurate CMR volumetric method to quantify ACC to LV filling. ACC ranges from 10%–40%, depending on age. J. Magn. Reson. Imaging 2013;37:860–864. © 2012 Wiley Periodicals, Inc.     

Impact of scar on SPECT assay of left ventricular contraction dyssynchrony

Purpose

Many patients presently receiving cardiac resynchronization therapy (CRT) do not respond. A disproportionate number of nonresponders have ischemic cardiomyopathy, with significant left ventricular (LV) scar burden. Current selection criteria, such as electrocardiography or echocardiography, may not reliably portray the magnitude of CRT-remediable LV contraction dyssynchrony. Although phase analysis of gated single photon emission computed tomography (SPECT) image data is increasingly appreciated as a tool for quantifying dyssynchrony, its use in the setting of scar has not been adequately evaluated.

Methods

Consecutive patients with ischemic (ICM, n?=?50) or nonischemic (NICM, n?=?39) cardiomyopathy underwent SPECT imaging prior to receiving CRT. In each patient, phase analysis of the raw images was performed to yield a phase standard deviation (PSD), an index which varies directly with the magnitude of dyssynchrony. ICM patient image data were also reanalyzed after scarred segments were stripped away.

Results

Raw image analysis demonstrated that PSD was significantly larger among ICM (57?±?17°) than NICM (35?±?13°, p?<?0.001) patients. Among ICM patients, PSD after stripping of scarred segments was significantly decreased (40?±?13°, p?<?0.001). Signals emanating from scarred segments were of low amplitude and presented a random pattern, suggestive of noise rather than indicating contraction.

Conclusion

PSD values may be spuriously increased by scar. These findings may be important when using SPECT in selecting ischemic cardiomyopathy patients for CRT.     

Cine MR determination of left ventricular ejection fraction

Cine MR imaging provides tomographic images of the heart with both high spatial and high temporal resolution. As many as 32 images per cardiac cycle can be acquired with up to four separate anatomic slices and a total imaging time of 128 cardiac cycles. End-diastolic and end-systolic volumes were determined in 11 patients, and ejection fractions were calculated. The results correlated linearly with those from cardiac catheterization (correlation coefficient of .88). We conclude that cine MR imaging can be used to obtain quantitative information about the heart and has the potential to become a valuable noninvasive means of cardiac evaluation.     

Characterization of right or left ventricular contraction heterogeneity using Fourier phase analysis

The standard deviation of the first harmonic Fourier phase histogram is an indicator of the contraction heterogeneity of the heart ventricles. This approach has been applied to analyse tomographic blood pool (^99mTc) examinations in a group of 32 patients with angiographically verified mainly right (RV) but also left (LV) kinetic disorders in relation to severe ventricular arrhythmias and suspicion of arrhythmogenic right ventricular dysplasia (ARVD). The reference group consisted of ten patients with low probability of cardiac kinetic abnormalities.Thick tomographic slices including both ventricles have been reconstructed in the horizontal long axis orientation from a series of 32 gated projections recorded over a 360° rotation. Separately for each ventricle the Fourier phase histograms have been computed and characterized by their standard deviations (PSD). Normal values (mean±standard deviation, LV=11°±5°, RV=12°±5°) were significantly lower (P<0.01 and P<0.001) than those measured in abnormal cases (LV=19°±10° and RV=31°±17°).Detailed analysis of the data supports the hypothesis of a primary RV disease in ARVD, with secondary LV extension. PSD seems to be a good predictor of an organic cardiac disease underlying ventricular arrhythmias and may be used for screening the patients.This work has been supported by a contract of the National Health Insurance Office of France (Caisse Nationale d'Assurance Maladie des Travailleurs Salariés)     

Radionuclide determination of right and left ventricular stroke volumes

The relationship between radionuclide and thermodilution measurement of stroke volumes (SV) was investigated in 30 patients without valvular regurgitation or intracardiac shunt (group A) at rest and during exercise. Both attenuated radionuclide right ventricular (RV) and left ventricular (LV) SV measurements correlated well with the SV determined by the thermodilution method (r=0.87 and r=0.93, all P< 0.001). The reliability of the radionuclide method to estimate SV was evaluated prospectively in two additional groups of patients. In 11 patients without valvular regurgitation or intracardiac shunt (group B) the radionuclide RVSV and LVSV closely approximated to thermodilution SV at rest and during exercise. In 15 patients with aortic regurgitation (group C) the radionuclide stroke volume ratio correlated well with the angiographic regurgitant fraction. Thus, both RVSV and LVSV and the severity of aortic regurgitation can be reliably measured with gated radionuclide ventriculography.     

Radionuclide determination of right and left ventricular stroke volumes

The relationship between radionuclide and thermodilution measurement of stroke volumes (SV) was investigated in 30 patients without valvular regurgitation or intracardiac shunt (group A) at rest and during exercise. Both attenuated radionuclide right ventricular (RV) and left ventricular (LV) SV measurements correlated well with the SV determined by the thermodilution method (r = 0.87 and r = 0.93, all P less than 0.001). The reliability of the radionuclide method to estimate SV was evaluated prospectively in two additional groups of patients. In 11 patients without valvular regurgitation or intracardiac shunt (group B) the radionuclide RVSV and LVSV closely approximated to thermodilution SV at rest and during exercise. In 15 patients with aortic regurgitation (group C) the radionuclide stroke volume ratio correlated well with the angiographic regurgitant fraction. Thus, both RVSV and LVSV and the severity of aortic regurgitation can be reliably measured with gated radionuclide ventriculography.     

Correlation of heart rate and radionuclide index of left ventricular contraction and relaxation

Since the cardiac function indices derived from radionuclide ventriculography (RNV) are considered to depend on the heart rate, we studied the relationship between systolic or diastolic indices and heart rates in patients with normal RNV and devised a method of correcting these indices according to the heart rate. For the systolic indices, the heart rate showed significant correlation with ET (r = -0.640), PER (r = 0.791) and TPE (r = -0.401) but not with EF, 1/3 EF, MNSER or 1/3 MNSER. For the diastolic indices, the heart rate correlated with FT (r = -0.938), RFT (r = -0.736), SFT (r = -0.803), 1/3 FF (r = -0.758), PFR (r = 0.759), 1/3 PFR (r = 0.742) and TPF (r = -0.389) but not with AFT, 1/3 MNDFR or AFF. These results indicate that many systolic and diastolic indices derived from RNV are affected by the heart rate. So when cardiac function is evaluated with the use of radionuclide indices, those which are independent of the heart rate should be used, or they should be corrected for the heart rate. As a method of correction, we proposed a rotating method obtained by manipulation of the regression equation of heart rates and indices. This new method is certain and easier to use when the correcting equations are set into a computer program.     

速度向量成像评估正常小儿左室短轴节段心肌的旋转运动

目的:通过速度向量成像(VVI)评估正常小儿左心室各节段心肌旋转运动的特征.方法:选取健康儿童50名,采集胸骨旁左室短轴心尖和心底切面的二维超声图像,脱机分析旋转角度和旋转速度、旋转角度和速度达峰时间,计算左室扭转角度,比较不同心肌节段旋转运动的差异,并分析其和年龄、心率的关系.结果:①正常小儿左室短轴的旋转运动表现为心底水平的顺时针方向和心尖水平的逆时针方向运动,心底水平的旋转角度和旋转速度从前壁到下壁逐渐递增,心尖水平的旋转角度从后间隔到侧壁依次递增,旋转速度从后间隔到后壁依次递增;②心底水平的旋转角度和旋转速度大于心尖水平的相应节段.心底水平各节段的旋转角度与年龄、心率无相关性(P＞0.05).心尖水平的后间隔旋转角度和年龄(r=0.354,P=0.012)、心率相关(r=0.401,P=0.004);③心底水平各节段的旋转角度的重复性较心尖水平各节段好(P＜0.05).结论:心底水平的旋转角度不受年龄、心率的影响,且重复性好,可更加准确地反映左室的局部心肌运动.     

彩超定量组织速度成像对肥厚型心肌病舒张运动的评价

目的：探讨定量组织速度成像技术评价肥厚型心肌病患者局部心肌舒张功能以及同步性运动的价值。方法：采集32例肥厚型心肌病患者及38例正常人的动态组织多普勒图像后,将心尖部左室三个切面测得的六个室壁共十二个节段之间的速度指标和时间指标与正常组进行比较。包括Ve、Va、TQ-E、TQ-Q、a（A峰结束至下一个E峰起点时间）、b（S峰持续时间）,以及TQ-E/TQ-Q。心功能指标：包括Ve/Va以及Tei指数。此外还分析了左室内同步性指标,包括Inter-TQ-E（同一节段6个壁间的差值）,Intra-TQ-E（同一壁内2个节段间的差值）以及Max-△TQ-E（左心室12个位点间的最大差值）。结果：正常人和肥厚型心肌病患者部分节段的TQ-E以及TQ-E/TQ-Q存在显著性差异（P〈0.05）。肥厚型心肌病患者Inter-TQ-E,Inter-TQ-E及Max-TQ-E均明显延长。肥厚型心肌病患者速度指标Ve,Va较正常人均有降低,尤其是Ve和正常组比较有非常显著差异（P〈0.01）。而Tei指数,Va/Ve均明显增高。结论：QTVI可定量评价肥厚型心肌病的舒张功能及室壁非同步运动,为临床准确评价其左室舒张功能提供了一种新方法。     

A noncomputerized count-based technique for the determination of resting left ventricular ejection fraction

A noncomputerized, count-based technique for the determination of left ventricular ejection fraction (LVEF), which does not use geometric assumptions of left ventricular shape, was developed. The noncomputerized technique and computerized multigated ventriculography using both fixed and variable region-of-interest (ROI) methods were performed on 16 patients. The LVEFs obtained with the noncomputerized technique correlated well with both the fixed ROI computerized technique (r = .87) and the variable ROI computerized technique (r = .86). It is concluded that when a computer is not available, the noncomputerized technique is a valid alternative for the determination of LVEF in resting patients in stable sinus rhythm.     

End-systolic stress–velocity relation and circumferential fiber velocity shortening for analysing left ventricular function in mice

Traditionally, analysing left ventricular (LV) performance relies on echocardiography by evaluating shortening fraction (SF) in mice. SF is influenced by load conditions. End-systolic stress–velocity (ESSV) relation and circumferential fiber velocity (VcF) shortening are more relevant parameters for evaluating systolic function regardless load conditions particularly in mice's models of heart failure.     

Assessment of regional left ventricular long-axis motion with MR velocity mapping in healthy subjects

The pattern of left ventricular long-axis motion during early diastole was assessed with magnetic resonance (MR) velocity mapping in 31 healthy volunteers. Regional long-axis velocity varied with time and position around the ventricle. During systole, the base descended toward the apex. The greatest magnitude of long-axis velocity occurred during early diastole. The lateral wall had the highest velocity (140 mm/sec ± 40 [mean ± standard deviation]); the anterior and inferior walls had lower velocities (96 mm/sec ± 27 and 92 mm/sec ± 34, respectively). The inferoseptal area consistently had the lowest velocities (87 mm/sec ± 40). Absolute values of peak early-diastolic velocity declined with age (r = ?.64, P <.001). Peak early-diastolic velocity was not dependent on heart rate (r =.014, P =.94). Regional variations in left ventricular wall motion were seen. MR velocity mapping is a useful technique for assessing regional left ventricular long-axis heart function.