BACKGROUND AND OBJECTIVES: Although the Tei index is a useful predictor of global ventricular function, it has not been investigated at the level of regional myocardial function. We therefore investigated the segmental tissue Doppler image derived-Tei index (TDI-Tei index) in patients with regional wall motion abnormalities. SUBJECTS AND METHODS: We prospectively studied 17 patients (mean age 62+/-9 years, 5 women) with left ventricular (LV) regional wall motion abnormalities. The Tei index, defined as the sum of isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT) divided by ejection time (ET), was measured in the basal and mid segments of the LV walls from standard apical views (4-, 2-, and 5-chamber views). We also obtained TDI velocity data in each segment. LV wall motion was classified as normal, hypokinetic, or akinetic, based on visual analysis. The TDI-Tei index, peak systolic myocardial velocity (Sm), early diastolic myocardial velocity (Em), and late diastolic myocardial velocity (Am) were analyzed in a total of 203 segments. RESULTS: Mean LV ejection fraction was 41.8+/-8.5%. TDI-Tei indices of dysfunctional segments (akinesis or hypokinesis, n=63) were significantly higher than those of normal segments (n=140) (0.714+/-0.169 vs. 0.669+/-0.135, p=0.041, respectively). Average values of TDI-Tei index, Sm, Em, and Am were 0.742+/-0.201, 4.206+/-1.336, 5.258+/-1.867, and 5.578+/-2.354 in akinetic segments; 0.677+/-0.101, 4.908+/-1.615, 5.369+/-2.121, and 5.542+/-2.492 in hypokinetic segments; and 0.669+/-0.135, 5.409+/-1.519, 6.108+/-2.356, and 6.719+/-2.466 in normal segments, respectively. A significant negative correlation was apparent between the TDI-Tei index and Sm (r=-0.302, p<0.001). CONCLUSION: These data suggest that the value of the segmental TDI-Tei index differs significantly according to regional function grade.
Contracts ; Humans ; Myocardial Contraction ; Prospective Studies ; Relaxation ; Ventricular Function

BACKGROUNDRight ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography.

METHODSTen patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony.

RESULTSThe left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm [(23.4 +/- 6.1)% vs (27.7 +/- 4.5)%, P = 0.01]. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm [64.13 degrees +/- 16.80 degrees vs 52.88 degrees +/- 9.26 degrees, P = 0.007]. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle.

CONCLUSIONRight atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.

Cardiac Pacing, Artificial ; Humans ; Myocardial Contraction ; Systole ; Ventricular Function, Left

This study evaluated the application of quantitative tissue velocity imaging (QTVI) in assessing regional myocardial systolic and diastolic functions in dogs with acute subendocardial ischemia. Animal models of subendocardial ischemia were established by injecting microspheres (about 300 microm in diameter) into the proximal end of left circumflex coronary artery in 11 hybrid dogs through cannulation. Before and after embolization, two-dimensional echocardiography, QTVI and real-time myocardial contrast echocardiography (RT-MCE) via intravenous infusion of self-made microbubbles, were performed, respectively. The systolic segmental wall thickening and subendocardial myocardial longitudinal velocities of risk segments before and after embolization were compared by using paired t analysis. The regional myocardial video intensity versus contrast time could be fitted to an exponential function: y=A.(1-exp(-beta.t)), in which the product of A and beta provides a measure of myocardial blood flow. RT-MCE showed that subendocardial normalized A.beta was decreased markedly from 0.99+/-0.19 to 0.35+/-0.11 (P<0.05) in 28 left ventricular (LV) myocardial segments after embolization, including 6 basal and 9 middle segments of lateral wall (LW), 8 middle segments of posterior wall (PW) and 5 middle segments of inferior wall (IW). However, there was no statistically significant difference in subepicardial layer before and after embolization. Accordingly, the ratio of A.beta of subendocardial myocardium to subepicardial myocardium in these segments was significantly decreased from 1.10+/-0.10 to 0.31+/-0.07 (P<0.05). Although the systolic wall thickening did not change 5 min after the embolization in these ischemic segments (29%+/-3% vs 31%+/-5%, P>0.05), the longitudinal peak systolic velocities (Vs) and early-diastolic peak velocities (Ve) recorded by QTVI were declined significantly (P<0.05). Moreover, the subendocardial velocity curves during isovolumic relaxation predominantly showed positive waves, whereas they mainly showed negative waves before the embolization. This study demonstrates that QTVI can more sensitively and accurately detect abnormal regional myocardial function and post-systolic systole caused by acute subendocardial ischemia.
Contrast Media ; Echocardiography/*methods ; Endocardium/physiopathology ; Microbubbles ; Myocardial Contraction/physiology ; Myocardial Ischemia/etiology ; Myocardial Ischemia/*physiopathology ; Myocardial Ischemia/*ultrasonography ; Myocardium/pathology ; Ventricular Function, Left/*physiology

Cardiac contractility variability (CCV) is a new concept which is introduced in the research field of cardiac contractility in recent years, that is to say, there are some disparities between cardiac contractilities when heart contracts. The changing signals of cardiac contractility contain a plenty of information on the cardiovascular function and disorder. In order to collect and analyze the message, we could quantitatively evaluate the tonicity and equilibrium of cardiac sympathetic nerve and parasympathetic nerve, and the effects of bio-molecular mechanism on the cardiovascular activities. By analyzing CCV, we could further understand the background of human being's heritage characteristics, nerve types, the adjusting mechanism, the molecular biology, and the adjustment of cardiac automatic nerve. With the development of the computing techniques, the digital signal processing method and its application in medical field, this analysis has been progressing greatly. By now, the assessment of CCV, just like the analysis of heart rate variability, is mainly via time domain and frequency domain analysis. CCV is one of the latest research fields in human cardiac signals being scarcely reported in the field of sports medicine; however, its research progresses are of important value for cardiac physiology and pathology in sports medicine and rehabilitation medicine.
Autonomic Nervous System ; physiology ; Exercise ; physiology ; Humans ; Myocardial Contraction ; physiology ; Phonocardiography ; methods ; Signal Processing, Computer-Assisted

PURPOSE: The objectives of this study were to estimate myocardial functions in patients with chronic renal failure by pulsed Doppler echocardiography, and investigate correlation between Doppler and disease parameters. METHODS: We studied 13 patients with chronic renal failure whose creatinine clearance rate less than 25ml/min. Using pulsed Doppler echocardiography with curve following method, we measured peak velocity, mean velocity, velocity-time integral and peak acceleration of aortic and pulmonic flow velocity curves, and peak velocity, mean velocity, area of rapid filling wave in early relaxation phase(E wave) and filling wave by atrial contraction in late relaxation phase(A wave) and A/E ratios of the peak velocity and area. And we compared these parameters with those of the normal controls, and then those with early chronic renal failure(less than 6 months of disease duration) and those with late chronic renal failure(more than 6 months of disease duration). RESULTS: In patients with early chronic renal failure, peak velocity, flow time and area of E wave of the mitral flow velocity curves were significantly decreased, and those of A wave were markedly increased and resulted in marked increase in A/E ratios of the peak velocity and area compared with those of the normal controls. In patients with late chronic renal failure, mitral A/E ratio of the peak velocity continued to be increased, and peak velocity, velocity-time integral and peak acceleration of the aortic flow velocity curves were significantly decreased but pulmonary velocity- time integral was increased markedly compared with those of the normal controls. CONCLUSIONS: Significant increase of mitral A/E ratio in patients with early chronic renal failure and appearance of significant change in aortic flow velocity curves in patients with late chronic renal failure suggest that abnormalities of myocardial relaxation seem to be present in early phase of the chronic renal failure and continued into late phase but abnormalities of myocardial contraction to appear on late phase of the chronic renal failure.
Acceleration ; Creatinine ; Echocardiography, Doppler, Pulsed* ; Humans ; Intussusception ; Kidney Failure, Chronic* ; Myocardial Contraction ; Recurrence ; Relaxation ; Ultrasonography

Adolescent ; Child ; Child, Preschool ; Electrocardiography ; Female ; Humans ; Male ; Myocardial Contraction ; Rheumatic Heart Disease ; physiopathology

Chronic Disease ; Electric Stimulation Therapy ; Heart Failure ; therapy ; Humans ; Myocardial Contraction

In order to culture cardiomyocytes or to observe the contractile function of adult mouse cardiomyocytes, it is necessary to isolate high-yield and high-quality cardiomyocytes at first. The mouse was injected with heparin (5,000 IU/kg, i.p.) 20 min prior to the experimental protocol, then was sacrificed by cervical dislocation. The heart was excised and the aorta was cannulated rapidly. The cannulated heart was mounted on a Langendorff perfusion apparatus with constant flow and perfusion pressure was monitored. The initial perfusion pressure was maintained at 40 mmHg by regulating the flow rate. The heart was digested by 0.05 % crude collagenase I at 37 degrees C and the enzymatic digestion was terminated immediately when the perfusion pressure was lowered to 28 mmHg. The heart was then cut off the cannula and the atria and aorta dissected away. The ventricular tissue was chopped and the single myocyte was dispersed gently by a wide tipped pipette. The viability of freshly isolated cardiomyocytes was more than 70 %. The cardiomyocytes were kept in Joklik's minimum essential medium containing 1 % BSA and 10 mmol/L BDM, then extracellular calcium was restored step-wise to a final concentration of 1.25 mmol/L. The viability of cardiomyocytes reduced to (40-50) % after 4 h standing. More than 90 % of rod-shaped cardiomyocytes were quiescent and had visible cross striations and sharp edges. The amplitude of unloaded shortening in cardiomyocytes was (9.72+/-0.43) % during 1.0 Hz stimulation, (11.28+/-0.43) % at 2.0 Hz and (11.40+/-0.45) % at 5.0 Hz. These results indicate that high yield and high quality cardiomyocytes can be obtained. In addition, the standards of identifying cardiomyocyte quality are concise and are suitable to culture the cardiomyocytes or to study the physiological function of cardiomyocytes.
Animals ; Cell Separation ; methods ; Cells, Cultured ; Female ; Male ; Mice ; Myocardial Contraction ; physiology ; Myocytes, Cardiac ; cytology ; physiology

Phonocardiogram exercise testing(PCGET) is a recently developed method for evaluating cardiac contractility and the cardiac reserve of patients with heart disease and of healthy subjects. In order to test the reliability of PCGET method in physical sport, the present author conducted a clinical study. The ratio of the amplitude of the first heart sound after PCGET to that recorded at rest was defined as an indicator, i.e. cardiac contractility reserve index (CCRI). PCGET was performed on 30 athletes and 30 non-athletes. The results showed that the average of CCRI was 10.139 +/- 2.631 in 30 athletes and 6.612 +/- 3.104 in 30 non-athletes. There was a significant difference between CCRI of the two groups (P < 0.01). Thus, PCGET might be a noninvasive, convenient and inexpensive technique to evaluate the cardiac reserve quantitatively for athletes.
Adolescent ; Adult ; Exercise Test ; methods ; Feasibility Studies ; Humans ; Myocardial Contraction ; physiology ; Phonocardiography ; methods ; Sports ; physiology

OBJECTIVETo investigate the value of ischemic myocardial viability assessment using interleaved T1-T2* magnetic resonance imaging.

METHODSThe left anterior descending coronary arteries (LAD) were occluded for 2 hours, followed by 1-hour reperfusion in 7 pigs. The hearts were then removed and perfused with a mixture of pig blood and crystalloid solution in 1:1 ratio. T1 relaxation times of the myocardium were measured with a TurboFLASH inversion-recovery sequence. The contrast agent, Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was then injected as a bolus into the aortic perfusion line (0.05 mmol/kg body wt). The first pass of the contrast agent through the heart was followed using the interleaved T1-T2* imaging sequence. Once the concentration of Gd-DTPA was in an equilibrium state, T1 relaxation times were measured again.

RESULTSThe percentage recovery of T2* intensity (PRT2*) at the maximum T1 intensity measured during the first pass of the contrast agent with the interleaved T1-T2* imaging was statistically different in normal myocardium (37 +/- 11)%, infarct rim (90 +/- 15)% and infarct core (100 +/- 5)%, F = 66.585, P = 0.000. Moreover, the infarcted regions shown on PR(T2)* maps matched well with the infarcted myocardium measured by TTC staining. The median of T(1) relaxation time in normal region, infarct rim and infarct core was 531 ms, 541 ms and 1298 ms, respectively (H = 6.284, P = 0.043). However, normal region could not be differentiated from infarct rim with T1 relaxation times (q = 0.082, P = 0.775).

CONCLUSIONInfarcted myocardium and ischemic myocardial viability can be correctly identified and evaluated by the interleaved T1-T2* magnetic resonance imaging in this model.

Animals ; Disease Models, Animal ; Female ; Magnetic Resonance Imaging ; methods ; Male ; Myocardial Contraction ; Myocardial Infarction ; diagnosis ; Myocardial Ischemia ; diagnosis ; Myocardium ; pathology ; Swine