Myocardial Postsystolic Motion in Ischemic and Not Ischemic Myocardium: The Clinical Value of Tissue Doppler

Considering Diastolic Dyssynchrony as a Predictor of Favorable Response in LV-Only Fusion Pacing Cardiac Resynchronization Therapy

Background: CRT improves systolic and diastolic function, increasing cardiac output. Aim of the study: to assess the outcome of LV diastolic dyssynchrony in a population of fusion pacing CRT. Methods: Diastolic dyssynchrony was measured by offline speckle-tracking-derived TDI timing assessment of the simultaneity of E″ and A″ basal septal and lateral walls. New parameters introduced: E″ and, respectively, A″ time (E″T/A″T) as the time difference between E″ (respectively, A″) peak septal and lateral wall. Patients were divided into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline characteristics: 62 pts (62 ± 11 y.o.) with idiopathic DCM, EF 27 ± 5.2%; 29% type III diastolic dysfunction (DD), 63% type II, 8% type I. Average follow-up 45 ± 19 months: LVEF 37 ± 7.9%, 34%SR, 61%R, 5%NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR with significant LV reverse remodeling (LV end-diastolic volume 193.7 ± 81 vs. 243.2 ± 82 mL at baseline, p < 0.0028) and lower LV filling pressures (E/E' 13.2 ± 4.6 vs. 11.4 ± 4.5, p = 0.0295). DD profile improved in 65% of R with a reduction in E/E' ratio (21 ± 9 vs. 14 ± 4 ms, p < 0.0001). Significant cut-off value calculated by ROC curve for LV diastolic dyssynchrony is E″T > 80 ms and A″T > 30 msec. Conclusions: The study identifies the cut-off values of diastolic dyssynchrony parameters as predictors of favorable outcomes in responders and super-responder patients with fusion CRT pacing. These findings may have important implications in patient selection and follow-up.

Left atrial phasic volumes and functions changes in asymptomatic patients with sarcoidosis: evaluation by three-dimensional echocardiography

BACKGROUND

Cardiac involvement is the leading cause of morbidity and death in patients with sarcoidosis. However, many patients remain asymptomatic until the late-stage. In this study, we investigated the left atrial (LA) phasic volumes and functions changes by three-dimensional (3D) echocardiography measurements in asymptomatic patients with sarcoidosis, which has good correlation with cardiac magnetic resonance imaging.

METHODS

In this cross-sectional study, 44 asymptomatic patients with sarcoidosis and 40 age, sex and BMI-matched healthy volunteers underwent two-dimensional (2D) and 3D-echocardiograpy. Standard echocardiographic and tissue Doppler imaging parameters were obtained. LA phasic volumes were assessed by 3D-echocardiography. From the 3D-echocardiography derived values, LA active, passive, and total emptying fraction (EF) were calculated.

RESULTS

All left ventricular ejection fractions (LVEF) obtained by 2D and 3D-echocardiography were normal (≥50%). While LA diameters (33.36 ± 4.23 vs. 30.57 ± 5.43) and E/e' septal annulus ratios (10.82 ± 1.79 vs. 9.27 ± 1.81) were significantly higher, A-wave (70.80 ± 5.81 vs. 74.51 ± 5.41) and e'septal annular velocities (6.48 ± 1.58 vs. 9.03 ± 1.63) were significantly lower in the sarcoidosis group as compared with control group, respectively. While 3D-echocardiography derived LA-minimum volume indices (LAVImin) (13.89 ± 2.75 vs. 12.23 ± 1.73) were significantly higher, 3D-echocardiography derived LA active EFs (AAEF) (30.78 ± 3.52 vs. 38.52 ± 4.75) and LA total EFs (TAEF) (47.71 ± 7.47 vs. 53.32 ± 5.81) were found to be significantly lower in the sarcoidosis group as compared with control group, respectively.

CONCLUSION

LAVImin, AAEF and TAEF calculated based on LA phasic volumes obtained by 3D-echocardiography may be promising indicators of subclinical cardiac involvement in asymptomatic patients with sarcoidosis.

Left Ventricle Phenotyping Utilizing Tissue Doppler Imaging in Premature Infants with Varying Severity of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is characterized by alveolar-capillary simplification and is associated with pulmonary hypertension (PH) in preterm infants. The contribution of left ventricle (LV) disease towards this severe BPD-PH phenotype is not well established. We aimed to describe the longitudinal trajectory of the LV function as measured by tissue Doppler imaging (TDI) and its association with BPD-PH. We retrospectively assessed prospectively acquired clinical and echocardiographic data from 77 preterm infants born between 2011 and 2013. We characterized the LV function by measuring systolic and diastolic myocardial velocities (s’, e’, a’), isovolumetric relaxation time (IVRT), and myocardial performance index with TDI at three time periods from 32 and 36 weeks, postmenstrual age through one year of age. We also measured post systolic motion (PSM), a marker of myocardial dysfunction that results from asynchronous movement of the ventricular walls, and not previously described in preterm infants. Patients were stratified into groups according to BPD severity and the presence of PH and compared over time. Conventional TDI measures of the LV function were similar between groups, but the septal PSM was significantly prolonged over the first year of age in patients with BPD-PH. PSM provides a novel objective way to assess the hemodynamic impact of lung and pulmonary vascular disease severity on LV function in preterm infants with BPD and PH.

Two-dimensional speckle tracking echocardiography in calves: feasibility and repeatability study

OBJECTIVES

To assess the feasibility and repeatability of two-dimensional speckle tracking echocardiography for the evaluation of left ventricular function in healthy calves.

ANIMALS

12 Holstein calves, 62 ± 11.6 days old; 75.25 ± 5.4 Kg.

METHODS

Observational study. Right parasternal short-axis views at papillary muscle level were recorded in standing calves and subsequently analyzed by two-dimensional speckle tracking for global and regional radial and circumferential strains and strain rates and radial displacement. Echocardiographic examinations were performed by 2 observers to evaluate intra- and interobserver repeatability and variability.

RESULTS

Two-dimensional speckle tracking was feasible in all calves. Automated tracking was better in systole than in diastole. Repeatability of the technique was good in calves. Systolic radial strain and strain rate peak values showed little variability compared with systolic circumferential strain and strain rate and to all diastolic measurements. Variability of the interobserver measurements was greater than the intraobserver measurements.

CONCLUSIONS

Two-dimensional speckle tracking is feasible in calves. As in other species, evaluation of systolic radial left ventricular function is more reliable than circumferential and diastolic left ventricular function.

Association between Left Ventricular Postsystolic Shortening and Diastolic Relaxation in Asymptomatic Patients with Systemic Hypertension

BACKGROUND

Few data have existed on myocardial postsystolic shortening (PSS) accounting for left ventricular (LV) diastolic dysfunction in systemic hypertension. We examined this relationship, along with clinical and other cardiac parameters, in asymptomatic patients with hypertension.

METHODS

We analyzed 104 patients on pharmacological treatment for hypertension who had no signs or symptoms of heart failure for conventional and speckle tracking echocardiography. The sum of the postsystolic index for multiple LV segments (total PSI) and global longitudinal strain (GLS) was computed and used as measures for global PSS and myocardial systolic function, respectively. The tissue Doppler e' and the speckle tracking-derived global strain rate during early diastole (e'sr) were obtained as indicators of LV relaxation. The circumferential end-systolic stress was also determined noninvasively and substituted for a measure of myocardial afterload.

RESULTS

Main variables that correlated with the e' and e'sr were shown to be age, LV mass index, left atrial volume index, GLS, and the total PSI. Multivariate analysis including gender, circumferential end-systolic stress, and the use of calcium channel blockers as possible covariates revealed that age (β = -0.29, P = 0.002), total PSI (β = -0.26, P = 0.008), and LV mass index (β = -0.25, P = 0.017) were significant independent determinants of e' and that age (β = -0.34, P < 0.001) and GLS (β = -0.28, P = 0.006) were of e'sr.

CONCLUSIONS

Our findings indicate that while depending on the degree of GLS, PSS may affect diastolic relaxation in patients with asymptomatic, but treated, hypertensive patients.

Standard and advanced echocardiography in takotsubo (stress) cardiomyopathy: clinical and prognostic implications

Echocardiography is frequently the initial noninvasive imaging modality used to assess patients with takotsubo cardiomyopathy (TTC). Standard transthoracic echocardiography can provide, even in the acute care setting, useful information about left ventricular (LV) morphology as well as regional and global systolic or diastolic function. It allows the differentiation of different LV morphologic patterns according to the localization of wall motion abnormalities. A "circumferential pattern" of LV myocardial dysfunction characterized by symmetric wall motion abnormalities involving the midventricular segments of the anterior, inferior, and lateral walls should be considered suggestive of TTC and included in the differential diagnosis of acute coronary syndromes. Moreover, advanced echocardiographic techniques, including speckle-tracking, myocardial contrast, and coronary flow studies, are providing mechanistic and pathophysiologic insights into this unique syndrome. Early identification of any potential complications (i.e., LV outflow tract obstruction, reversible moderate to severe mitral regurgitation, right ventricular involvement, thrombus formation, and cardiac rupture) are crucial for the management, risk stratification, and follow-up of patients with TTC. Because of the dynamic evolution of the syndrome, comprehensive serial echocardiographic examinations should be systematically performed. This review focuses on these aspects of imaging and the increasing understanding of the clinical and prognostic utility of echocardiography in TTC.

The tissue Doppler imaging derived post-systolic velocity notch originates at the aortic annulus

Background

A distinct velocity pattern represented by a "notch" is observed during the time interval between the end of the systolic and the onset of the early diastolic velocity wave on longitudinal myocardial velocity curve. The origin of the post-systolic velocity notch (PSN) has not been resolved.

Methods

The high frame rate color tissue Doppler imaging of the apical longitudinal axis was performed in 32 healthy subjects.

Results

The time delays of the PSN onset at the posterior aortic wall (AW), the mid anteroseptal wall (MAS) and the posterior mitral annulus (MA) relatively to the anterior aortic annulus (AA) were found to be significantly longer than zero (5.1 ± 2.2, 6.0 ± 2.3, 6.8 ± 2.8 ms; p < 0.001). The amplitude was the highest at the AA when compared to the AW, the MAS and the MA (4.77 ± 1.28 vs. 2.88 ± 1.11, 2.15 ± 0.73, 2.44 ± 1.17 cm/s; p < 0.001). A second PSN spike was identifiable in 10/32 (31%) of the studied subjects at the AA. Of these, 9 (28%) exhibited a second PSN spike at the AW, 3 (9%) at the MAS and no one at the MA.

Conclusion

The AA represents the site of the earliest onset and maximal amplitude of the PSN on the longitudinal velocity curve suggesting its mechanism to be that of an energy release at the instant of the aortic valve closure causing an apically directed acceleration of the myocardium. A substantial number of healthy subjects exhibit a second PSN spike predominantly at the level of the AA. Its mechanism remains to be elucidated.

Imaging techniques for cardiac strain and deformation: comparison of echocardiography, cardiac magnetic resonance and cardiac computed tomography

Myocardial function assessment is essential for determining the health of the myocardium. Global assessment of myocardial function is widely performed (by estimating the ejection fraction), but many common cardiac diseases initially affect the myocardium on a regional, rather than global basis. Regional myocardial wall motion can be quantified using myocardial strain analysis (a normalized measure of deformation). Myocardial strain can be measured in terms of three normal strains (longitudinal strain, radial strain and circumferential) and six shear strains. Cardiac MRI (cMRI) is usually considered the reference standard for measurement of myocardial strain. The most common cMRI method, termed tagged cMRI, allows full, 3D assessment of regional strain. However, due to its complexity and lengthy times for analysis, tagged cMRI is not usually used outside of academic centers. Tagged cMRI is also primarily used only in research studies. Echocardiography combined with tissue Doppler imaging or a speckle tracking technique is now widely available in the clinical setting. Myocardial strain measurement by echocardiography shows reasonable agreement with cMRI. Limited standardization and differences between vendors represent current limitations of the technique. Cardiac computed tomography (CCT) is the newest and most rapidly growing modality for noninvasive imaging of the heart. While CCT studies are most commonly applied to assess the coronary arteries, CCT is easily adapted to provide functional information for both the left and right ventricles. New methods for CCT assessment of regional myocardial function are being developed. This review outlines the current literature on imaging techniques related to cardiac strain analysis and discusses the strengths and weaknesses of various methods for myocardial strain analysis.

Cardiac changes in horses with atypical myopathy

BACKGROUND

Atypical myopathy (AM) is an acute, fatal rhabdomyolysis in grazing horses that mainly affects skeletal muscles. Postmortem examinations have shown that myocardial damage also occurs. Limited information is available on the effect of AM on cardiac function in affected and surviving horses.

OBJECTIVES

To describe electrocardiographic and echocardiographic changes associated with AM in the acute stage of the disease and after follow-up.

ANIMALS

Horses (n = 12) diagnosed with AM in which cardiac ultrasound examination and ECG recording were available.

METHODS

All horses underwent clinical examinations, serum biochemistry, electrocardiography, and echocardiography. Four surviving horses underwent the same examinations after 2-10 weeks.

RESULTS

All but 1 horse had increased cardiac troponin I concentrations and 10 horses had ventricular premature depolarizations (VPDs). All horses had prolonged corrected QT (QT(cf) ) intervals on the day of admission and abnormal myocardial wall motion on echocardiography. One of the surviving horses still had VPDs and prolonged QT(cf) at follow-up after 10 weeks.

CONCLUSIONS AND CLINICAL IMPORTANCE

The AM results in characteristic electrocardiographic and echocardiographic changes and may be associated with increased cardiac troponin I concentrations and VPDs. In survivors, abnormal cardiac function still may be found at follow-up after 10 weeks. Additional research in a larger group of horses is necessary to identify the long-term effects of AM on cardiac function.

Impact of antihypertensive treatment on left ventricular systolic dyssynchrony in treatment-naïve hypertensive patients

Dyssynchrony is common in asymptomatic patients with hypertension. We sought to investigate the impact of antihypertensive treatment on dyssynchrony in patients with hypertension. A total of sixty patients who had uncomplicated hypertension that had never been treated (treatment-naïve hypertensive patients) underwent echocardiographic evaluations of left ventricular (LV) dyssynchrony at baseline and after a 6-month treatment with antihypertensive drugs. The measured parameters were as follows: (1) the s.d. of 12 LV-segment time-to-peak systolic velocities (Ts-SD12), and (2) the maximal difference between peak systolic velocities of any 2 of the 12 segments (Ts-Max). Patients with Ts-SD12 ≥ 33 ms or Ts-Max ≥ 100 ms were regarded as having LV systolic dyssynchrony. Patients with systolic dyssynchrony (group 1, n = 29) and without systolic dyssynchrony (group 2, n = 31) were compared. Among the patients in group 1, antihypertensive treatment significantly improved LV systolic dyssynchrony (ΔTs-SD12, -13.1 ms; P<0.001 and ΔTs-Max, -34.0 ms; P = 0.003), whereas it did not demonstrate additional benefit among group 2 patients. The change in LV systolic dyssynchrony was significantly associated with changes in the mean annulus E' velocity, mean annulus S' velocity and mean annulus E'/A' ratio, but not with changes in blood pressure and LV mass index. It is likely that chronic antihypertensive treatment could reverse the LV systolic dyssynchrony and simultaneously improve subclinical systolic and diastolic function in patients with hypertension and LV systolic dyssynchrony.

Impaired subendocardial wall thickening and post-systolic shortening are signs of critical myocardial ischemia in patients with flow-limiting coronary stenosis

BACKGROUND

The early diagnosis of myocardial ischemia is still challenging. The aim of the present study was to determine whether subendocardial hypokinesis and post-systolic contraction could be early markers of myocardial ischemia.

METHODS AND RESULTS

Thirty-one consecutive patients with flow-limiting severe coronary stenosis but without visually abnormal left ventricular wall motion underwent quantitative echocardiography. Myocardial strain was measured using layer-by-layer analysis in severely hypoperfused segments. Radial strain (RS) was measured in the subendocardial, subepicardial, and total wall (innerRS, outerRS, and totalRS, respectively). Circumferential strain (CS) was also measured as 3 separate layers: subendocardial, mid-layer, and subepicardial layers (innerCS, midCS, and outerCS, respectively). Post-systolic shortening (PSS) was defined as the peak strain after end systole, and post-systolic strain index (PSI) was calculated as PSS divided by end-systolic strain. TotalRS was similar between ischemic and normally perfused segments, but innerRS and inner/outer RS ratio were significantly smaller in the ischemic segments than in corresponding segments in healthy subjects. Receiver operating characteristic analysis identified an optimum cut-off for PSI of 0.6. The combined criteria of inner/outer RS ratio <1.0 and PSI >0.6 achieved 95% specificity for the presence of flow-limiting stenosis.

CONCLUSIONS

Combined assessment of both subendocardial contractile impairment and PSS is very useful in identifying a severely hypoperfused left ventricular wall even without visual wall motion abnormality.

Strain measurements during adenosine triphosphate infusion before and after percutaneous coronary intervention

BACKGROUND

In regional myocardial ischemia, contractile delay develops, which can be assessed by measuring time to peak strain (TPS) on tissue Doppler imaging. The aims of the present study were to clarify the usefulness of TPS measurements during adenosine triphosphate (ATP) stress in assessing myocardial ischemia and to evaluate whether prolongation of TPS disappears immediately after percutaneous coronary intervention (PCI) or not.

METHODS AND RESULTS

A total of 26 patients underwent strain measurements before and after PCI. Corrected TPS for heart rate (TPSc) in target regions and in control regions were measured both at baseline and during ATP infusion. TPSc ratio was calculated as a ratio of TPSc during ATP stress to TPSc at baseline. TPSc in the target region significantly increased during ATP infusion before PCI, which was significantly longer than hyperemic TPSc in control regions. Accordingly, TPSc ratio in the target regions before PCI was significantly greater than that in control regions (1.22+/-0.17 vs 0.96+/-0.09, respectively, P<0.0001). Following PCI, the TPSc ratio in the target regions significantly decreased to 0.98+/-0.05 (P<0.0001). Receiver operating characteristic curve analysis provided a cut-off of 1.04 in TPSc ratio for detecting myocardial ischemia with a sensitivity of 93% and specificity of 93%.

CONCLUSIONS

TPS measurements during ATP stress differentiated target from control myocardium before PCI. The prolongation of TPSc disappeared immediately after PCI.

Relationship between post-systolic motion during dobutamine stress echocardiography and functional recovery of myocardium after successful percutaneous coronary intervention

BACKGROUND AND OBJECTIVES

Doppler myocardial imaging (DMI) has been suggested as a method of quantifying inducible ischemia during dobutamine stress echocardiography (DSE). Post-systolic motion (PSM) detected by DMI is related to peri-infarct ischemia during DSE. We hypothesized that PSM during DSE would predict recovery of dysfunctional myocardium after successful percutaneous coronary intervention (PCI).

SUBJECTS AND METHODS

Thirty patients with dysfunctional myocardium in the left anterior descending coronary artery (LAD) territory were divided into two groups according to improvement of wall motion score index (WMSI) in the LAD territory at 6 months after successful PCI of the LAD. DMI was evaluated in the LAD territory during DSE. Fifteen patients showed improved WMSI (1.42+/-0.39) while the other 15 had unchanged WMSI (1.75+/-0.46) 1 month after PCI. Myocardial velocity was measured in the mid-septal, apico-septal, and basal anterior segments of the LAD artery territory. PSM was defined as a positive wave appearing after the curve of systolic ejection had reached the zero line.

RESULTS

Although there was no difference between resting PSMs in both groups, PSM during DSE was significantly higher in the improved WMSI group than in the WMSI group where it was unchanged.

CONCLUSION

PSM during DSE predicts recovery of dysfunctional myocardium after successful PCI.

Benefit of warm water immersion on biventricular function in patients with chronic heart failure

Background

Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water) could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety.

The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI) and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP).

Methods

Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, _peakVO₂ 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C).

Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly.

Results

During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p < 0.0001, respectively). Heart rate decreased from 73 ± 12 to 66 ± 11 bpm (p < 0.0001), mean arterial pressure from 92 ± 14 to 86 ± 16 mmHg (p < 0.01), and systemic vascular resistance from 31 ± 7 to 22 ± 5 resistant units (p < 0.0001).

There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy.

Conclusion

Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

Tissue Doppler and strain imaging: anything left in the echo-lab?

Medline research indicates that an increasing number of manuscripts have been published in the last decade claiming, the feasibility and the potential clinical role of tissue Doppler and strain/strain rate imaging. However, despite this amount of scientific evidence, these technologies are still confined to dedicated, high-tech, research-oriented echocardiography laboratories. In this review we have critically evaluated these techniques, analysing their physical principles, the technical problems related to their current clinical application, and the future perspectives. Finally, this review explores the reasons why these technologies are still defined "new technologies" and the impact of their implementation on the current clinical activity of an echocardiography laboratory.

Segmental early relaxation phenomenon as determined by tissue Doppler imaging

BACKGROUND

The early diastolic peak velocity of left ventricular (LV) wall segment has always been thought to appear in the rapid filling phase. However, we find a segmental early relaxation phenomenon (SERP), characterized by an early diastolic peak velocity lying in the isovolumic relaxation (IVR) period. The present study aimed to investigate the characteristics of SERP segments with tissue Doppler imaging (TDI) echocardiography.

METHODS

TDI was performed in 119 patients with known or suspected coronary heart disease (CHD) and 60 normal subjects. The segmental early diastolic velocity pattern was classified as normal pattern (NP), postsystolic shortening (PSS) and SERP.

RESULTS

Segmental early diastolic velocity pattern was significantly associated with actual coronary diameter stenosis, relative coronary stenosis, wall motion score, and segmental location in LV wall. Compared with other segments, SERP segments had a higher IVR velocity and lower early diastolic peak velocity.

CONCLUSION

SERP most frequently occurs in the distribution of artery with the relatively mildest stenosis, and is more likely accompanied by simultaneous PSS elsewhere in LV wall, which occurs most frequently in the distribution of artery with the relatively most severe stenosis. A decreased early diastolic peak velocity of SERP segment dose not necessarily mean impaired myocardial relaxation.

Apical Myocardial Stunning in a Large Size Porcine Model Assessed by Strain and Strain Rate Echocardiography

BACKGROUND

Warm ischemia and subsequent reperfusion of the heart can induce a temporary dysfunction known as myocardial stunning. The aim of this study was to investigate the ability of tissue Doppler imaging (TDI) to quantify longitudinal myocardial stunning close to the apex, and perform a comparison with sonomicrometry using a well-established large size porcine model.

METHODS

In anesthetized pigs, postischemic myocardial stunning was induced by occluding LAD for 15 min followed by 90 min reperfusion (n = 7). Long-axis strain and strain rate was quantified by both TDI and sonomicrometry.

RESULTS

During reperfusion, peak systolic strain measured by TDI decreased from -11.2% (+/-3.0) at baseline to -4.9% (+/-3.6), -3.4% (+/-2.9), and -4.3% (+/-5.0) at 30, 60, and 90 min, respectively (all P < 0.007). Postsystolic strain increased from -1.3% (+/-1.6) at baseline to -6.4% (+/-4.4), -4.8% (+/-4.0), and -5.2% (+/-2.7) by TDI in the reperfusion phase (all P < 0.048 except at 60 min of reperfusion (P = 0.081)). Postsystolic index increased from 0.10 (+/-0.13) at baseline to 0.56 (+/-0.24), 0.54 (+/-0.30), and 0.64 (+/-0.37) subsequently (all P < 0.012). [Correction added after online publication 30-May-2007: In the preceding sentence, the phrase 'Postsystolic index decreased from 0.10 (+/-0.13)' was changed to 'Postsystolic index increased from 0.10 (+/-0.13).'] Difference-mean and line of identity plots did not disclose any systematic error, but revealed substantial variation, indicating a mismatch between TDI and sonomicrometry.

CONCLUSIONS

It is feasible to quantify postischemic myocardial stunning by TDI in a large size porcine model using longitudinal postsystolic shortening, and postsystolic index as indicators. TDI and sonomicrometry data reach the same end point, but the two techniques are not interchangeable when investigating myocardial stunning close to apex in reference to longitudinal strain and strain rate.