Isovolumetric Relaxation Period Research Articles

Hypoxia-Induced Myocardial Hypertrophy Companies with Apoptosis Enhancement and p38-MAPK Pathway Activation.

Li, Xiaoxu, Zhijun Pu, Gang Xu, Yidong Yang, Yu Cui, Xiaoying Zhou, Chenyuan Wang, Zhifeng Zhong, Simin Zhou, Jun Yin, Fabo Shan, Chengzhong Yang, Li Jiao, Dewei Chen, and Jian Huang. Hypoxia-induced myocardial hypertrophy companies with apoptosis enhancement and p38-MAPK pathway activation. High Alt Med Biol. 00:00-00, 2024. Background: Right ventricular function and remodeling are closely associated with symptom severity and patient survival in hypoxic pulmonary hypertension. However, the detailed molecular mechanisms underlying hypoxia-induced myocardial hypertrophy remain unclear. Methods: In Sprague-Dawley rats, hemodynamics were assessed under both normoxia and hypobaric hypoxia at intervals of 7 (H7), 14 (H14), and 28 (H28) days. Morphological changes in myocardial tissue were examined using hematoxylin and eosin (HE) staining, while myocardial hypertrophy was evaluated with wheat germ agglutinin (WGA) staining. Apoptosis was determined through TUNEL assays. To further understand the mechanism of myocardial hypertrophy, RNA sequencing was conducted, with findings validated via Western blot analysis. Results: The study demonstrated increased hypoxic pulmonary hypertension and improved right ventricular diastolic and systolic function in the rat models. Significant elevations in pulmonary arterial systolic pressure (PASP), mean pulmonary arterial pressure (mPAP), right ventricular mean pressure (RVMP), and the absolute value of +dp/dtmax were observed in the H14 and H28 groups compared with controls. In addition, right ventricular systolic pressure (RVSP), -dp/dtmax, and the mean dp/dt during isovolumetric relaxation period were notably higher in the H28 group. Heart rate increased in the H14 group, whereas the time constant of right ventricular isovolumic relaxation (tau) was reduced in both H14 and H28 groups. Both the right heart hypertrophy index and the heart weight/body weight ratio (HW/BW) were elevated in the H14 and H28 groups. Myocardial cell cross-sectional area also increased, as shown by HE and WGA staining. Western blot results revealed upregulated HIF-1α levels and enhanced HIF-2α expression in the H7 group. In addition, phosphorylation of p38 and c-fos was augmented in the H28 group. The H28 group showed elevated levels of Cytochrome C (Cyto C), whereas the H14 and H28 groups exhibited increased levels of Cleaved Caspase-3 and the Bax/Bcl-2 ratio. TUNEL analysis revealed a rise in apoptosis with the extension of hypoxia duration in the right ventricle. Conclusions: The study established a link between apoptosis and p38-MAPK pathway activation in hypoxia-induced myocardial hypertrophy, suggesting their significant roles in this pathological process.

A Study of the Usefulness of Tissue Doppler Imaging for the Diagnosis of Coronary Artery Disease in Patients with Left Bundle Branch Block

Abstract Background: In patients with left bundle branch block (LBBB), the diagnosis of ischemia by noninvasive modalities is cumbersome. Most of them such as stress tests, nuclear imaging, and magnetic resonance imaging have limitations in the detection of ischemia in this subset. The postsystolic motion (PSM) during the isovolumetric relaxation period on tissue Doppler imaging (TDI) is a sensitive and specific marker of ischemia. We aimed to see whether the TDI parameters can detect coronary artery disease (CAD) in patients with LBBB. Materials and Methods: Patients with LBBB (n = 64) who underwent coronary angiography were divided into two groups. Group A (n = 30) included patients with left anterior descending (LAD) artery stenosis of ≥70%, and group B (n = 34) included patients without LAD stenosis. All patients underwent TDI and various myocardial tissue velocity parameters were analyzed to detect the presence of CAD. P < 0.05 was considered significant. Results: The TDI of the mid-interventricular septum showed a higher delayed amplitude of PSM (>100 ms after aortic valve closure), lower myocardial systolic (Sm), and early diastolic (Em) velocities, and a higher late diastolic (Am) velocity in group A when compared to group B (all were significant, P < 0.0001). Both the ratios Sm/PSM and Em/Am were significantly lower in group A compared to group B (P < 0.0001). On receiver operating characteristic curve analysis to predict the presence of significant LAD stenosis, the value of Sm/PSM ratio <0.8 showed the best combination of sensitivity (78%) and specificity (96%) with an area under the curve of 0.936. Conclusion: TDI, a noninvasive imaging modality, is reliable and effective in identifying myocardial ischemia in patients with LBBB.

Quantifying preload alterations using a sensitive chest-mounted accelerometer

Abstract Seismocardiography (SCG) is a technology where the chest wall vibrations from the beating heart are measured using a highly sensitive accelerometer. SCG offers continuous measurement of cardiac function and potential applications include remote monitoring, diagnostic assessments, prognostic health checks and biventricular pacemaker optimization. Aim In the current study we examined how changes in preload influence SCG time intervals, by acute saline infusion. Methods We included twenty-six subjects, sixteen subjects with cardiac disease such as hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic valve disease or ischemic heart disease (age 45.8±17.7 years and 93% male) and ten subjects without known cardiac conditions (age 42.1±14.4 years and 70% male). SCG was recorded from the xiphoid process using a custom-made sensor before and after acute infusion saline (median 2.0 L). The SCG signals were sampled with 5000 samples per second in 60 seconds, the individual heartbeats were identified using a dedicated segmentation algorithm and an average SCG beat was computed and used for the data analysis. Using a recently proposed nomenclature the following SCG fiducial points was identified: Es which coinciding with mitral valve closure, Gs which to some degree coincides with aortic opening, Bd coinciding with aortic valve closure and Fd coinciding with mitral valve opening [1]. The Es-Gs time interval was used as a measure of isovolumetric contraction time (IVCT), the Gs-Bd time interval was used as an estimate of ejection time (ET) and the Bd-Fd time interval as an estimate of isovolumetric relaxation time (IVRT). Paired t-test was used to test for significant response after infusion, while a two sample t-test was used to test for a significant difference in the observed response in subjects with or with our cardiac disease. Results For two subjects SCG after infusion was not obtained thus, twenty-four subjects were included in the final data analysis. In the whole group, acute saline infusion shortened the IVRT (Bd-Fd) from 91.0±15.3 ms to 82.7±15.3 ms (p=0.004) and prolonged the ET (Gs-Bd) from 329.4±35 ms to 343.4±33 ms (p<0.001). There was no significant change in IVCT (Es-Gs) which was 39.5±15.1 ms at baseline and 38.1±14.9 ms post-infusion (p=0.88). There was no significant difference in response between subjects with or without cardiac disease. Conclusion Increase in preload shortened the SCG time intervals related to the isovolumetric relaxation period and prolonged the period related to ejection time. SCG time intervals capture changes in preload, which demonstrates that the SCG is a potential modality for quantification of cardiac dynamics. Funding Acknowledgement Type of funding sources: None.

Quantifying preload alterations using a sensitive chest-mounted accelerometer

Abstract Seismocardiography (SCG) is a technology where the chest wall vibrations from the beating heart are measured using a highly sensitive accelerometer. SCG offers continuous measurement of cardiac function and potential applications include remote monitoring, diagnostic assessments, prognostic health checks and biventricular pacemaker optimization. Aim In the current study we examined how changes in preload influence SCG time intervals, by acute saline infusion. Methods We included twenty-six subjects, sixteen subjects with cardiac disease such as hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic valve disease or ischemic heart disease (age 45.8±17.7 years and 93% male) and ten subjects without known cardiac conditions (age 42.1±14.4 years and 70% male). SCG was recorded from the xiphoid process using a custom-made sensor before and after acute infusion saline (median 2.0 L). The SCG signals were sampled with 5000 samples per second in 60 seconds, the individual heartbeats were identified using a dedicated segmentation algorithm and an average SCG beat was computed and used for the data analysis. Using a recently proposed nomenclature the following SCG fiducial points was identified: Es which coinciding with mitral valve closure, Gs which to some degree coincides with aortic opening, Bd coinciding with aortic valve closure and Fd coinciding with mitral valve opening [1]. The Es-Gs time interval was used as a measure of isovolumetric contraction time (IVCT), the Gs-Bd time interval was used as an estimate of ejection time (ET) and the Bd-Fd time interval as an estimate of isovolumetric relaxation time (IVRT). Paired t-test was used to test for significant response after infusion, while a two sample t-test was used to test for a significant difference in the observed response in subjects with or with our cardiac disease. Results For two subjects SCG after infusion was not obtained thus, twenty-four subjects were included in the final data analysis. In the whole group, acute saline infusion shortened the IVRT (Bd-Fd) from 91.0±15.3 ms to 82.7±15.3 ms (p=0.004) and prolonged the ET (Gs-Bd) from 329.4±35 ms to 343.4±33 ms (p<0.001). There was no significant change in IVCT (Es-Gs) which was 39.5±15.1 ms at baseline and 38.1±14.9 ms post-infusion (p=0.88). There was no significant difference in response between subjects with or without cardiac disease. Conclusion Increase in preload shortened the SCG time intervals related to the isovolumetric relaxation period and prolonged the period related to ejection time. SCG time intervals capture changes in preload, which demonstrates that the SCG is a potential modality for quantification of cardiac dynamics. Funding Acknowledgement Type of funding sources: None.

P2602Inhaled iloprost improves echocardiographic myocardial performance during exercise in heart failure with preserved ejection fraction

Abstract Introduction The pathophysiology of HFpEF is complicated and treatments that improve outcomes in HFrEF have no substantial benefits in HFpEF. Impairments in LV global longitudinal strain (GLS) and LV diastolic function parameters have been regarded as novel echocardiographic markers to predict cardiovascular events in HFpEF. Preliminary trials indicate that iloprost, an inhaled prostacyclin analougue, improves exercise hemodynamics in both patients with pulmonary artery hypertension and pulmonary hypertension associated with HFpEF. Purpose We aim to investigate the impact of inhaled iloprost on LV global longitudinal strain, LV diastolic function and RV function during exercise in HFpEF population. Methods 34 patients diagnosed with HFpEF were included with exclusion of severe pulmonary, coronary artery, valvular heart and pericardial diseases. Subjects were randomized 1:1 to inhalation of iloprost or placebo. Transthoracic echocardiography was performed at rest and after 6-minute supine bicycle exercise at 20-Watt workload. We utilized tissue speckle tracking by QLAB software to derive LV GLS and global strain rate during LV isovolumetric relaxation period (SRIVR). E/e', E/SRIVR, tricuspid regurgitation pressure gradient (TRPG), tissue Doppler imaging of RV lateral tricuspid annulus and tricuspid annular plane systolic excursion (TAPSE) were measured to evaluate changes of myocardial performance. Results LV GLS during exercise significantly enhanced after iloprost use. E/SRIVR, a novel predictor of LV filling pressure, was significantly decreased. E/e' was also lower in iloprost group by trend. Improvements in RV function and degree of pulmonary hypertension during exercise with iloprost were observed in this study. Echocardiographic myocardial function endpoints during 20-Watt excercise between iloprost and placebo groups Iloprost (N=17) Placebo (N=17) P value LV global longitudinal strain, % −4.96±1.20 −0.75±3.00 <0.001 E/SRIVR, cm 206.41±113.55 454.13±262.98 0.005 E/e' mean 10.77±2.39 14.41±12.14 0.235 TAPSE, cm 2.62±0.62 2.37±0.56 0.221 TRPG, mmHg 28.37±12.47 44.25±9.29 <0.001 TDI lateral tricuspid annulus, cm/s 16.41±4.61 14.77±2.92 0.222 Effects of iloprost at rest and exercise Conclusions Our study is the first to demonstrate that, in patients with HFpEF, inhaled iloprost favorably enhances LV GLS reserves, decreases LV diastolic filling load, reduces pulmonary hypertension and thereby improves RV function during exercise. Acknowledgement/Funding This work was supported in part by the National Science Council of the Republic of China, Taiwan (NSC107-2314-B-002-265-MY3)

Application value of vector flow mapping in assessing the degrees of coronary artery stenosis

Objective To quantify the left ventricular flow field characteristics of different phases of cardiac cycle in patients with different degrees of coronary artery stenosis by using vector flow mapping (VFM), and explore the value of quantitative parameters of VFM in diagnosis of degrees of coronary artery stenosis in patients with coronary heart disease. Methods Eighty-four patients with coronary artery stenosis showed by coronary angiography served as case group. According to the results of coronary angiography, all the patients of case group were divided into 3 groups: mild stenosis group, moderate stenosis group and severe stenosis group. Forty-five healthy adult volunteers were selected as control group. The quantitative parameters, including average energy loss (EL-base, EL-mid, EL-apex) and circulation (vortex area, circulation), were measured in the different periods of VFM mode. The difference of parameters were evaluated between case group and control group during different periods. E/e′ was derived via dual-Doppler imaging technology and correlation was analyzed between aEL, circulation, E/e′(L) and E/e′(S), separately. ROC curve was used to analyze aEL in severe stenosis group, and to evaluate the diagnostic efficacy of aEL in different cardiac cycles. Results ①Compared with the control group, aEL in global and regional segment of left ventricle in the severe stenosis group were significantly increased during isovolumetric relaxation period, reduced filling period, atrial systolic phase and isovolumic contraction period (all P<0.05). And the aEL in global and regional segment of left ventricular in the moderate stenosis group were significantly increased during reduced filling period, atrial systolic phase and isovolumic contraction period (all P<0.05). And the aEL in middle segment of left ventricular in the mild stenosis group was significantly increased during reduced filling period (P<0.05). ②Compared with the control group, the vortex area and circulation intensity in left ventricular of the severe stenosis group were significantly increased during isovolumetric relaxation period, reduced filling period, atrial systolic phase and isovolumic contraction period(P<0.05). ③In case group, there were positive correlations between aEL with E/e′(L) or E/e′(S) at global and regional segment of rapid filling phase and atrial systolic phase. And there were positive correlations between the vortex area or circulation intensity and E/e′(L) or E/e′(S) during reduced filling period and atrial systolic phase. Conclusions VFM can effectively evaluate the flow field characteristics of left ventricle in patients with coronary heart disease. The quantitative parameters of VFM can reflect the extent of coronary artery stenosis in some extent. Key words: Vector flow mapping; Coronary stenosis; Energy loss; Circulation

Antihypertensive treatment improves left ventricular diastolic function in patients with chronic kidney disease.

In patients with chronic kidney disease (CKD), hypertension (HP) is associated with the development of left ventricular (LV) diastolic dysfunction. However, the impact of antihypertensive treatment on LV diastolic function has not been well studied in CKD patients. Recently, two-dimensional speckle-tracking echocardiography (2DSTE) has emerged as a sensitive and quantitative assessment of LV diastolic function. The present study used 2DSTE to investigate the effects of antihypertensive treatment on LV diastolic function in patients with CKD and untreated HP. The study comprised 134 patients with CKD and untreated HP. The patients received blood pressure (BP)-lowering therapy for six months. The patients were clinically and echocardiographically evaluated at baseline and after 6 months of therapy. It was found that the mean systolic BP (SBP) and diastolic BP (DBP) at baseline were 154.0±7.0 and 92.6±10.2 mmHg, respectively, decreasing to 121.2±7.3 and 74.6±10.4 mmHg, respectively (P<0.05 for both) after the 6-month treatment period. Moreover, the mean peak LV strain rate during the isovolumetric relaxation period (SRIVR) and early diastole (SRE) improved following treatment (from 0.23±0.10 to 0.42±0.10 sec-1 and from 0.58±0.25 to 1.07±0.24 sec-1, respectively; P<0.05 for both). Notably, the patients with CKD stage ≥3 were more likely to demonstrate an improvement in diastolic speckle-tracking parameters than those with CKD stage 1 or 2. For the entire population, the change (Δ) in B-type natriuretic peptide (BNP) level correlated with changes in echocardiographic parameters between baseline and follow-up, among which ΔSRIVR presented the highest correlation coefficient (r=-0.73, P<0.01). On multivariate analysis, the independent predictors of ΔSRIVR were found to include baseline CKD stage, SBP and SRIVR. This study demonstrated that LV diastolic function was improved in CKD patients following antihypertensive treatment, particularly in patients with CKD stage ≥3, higher baseline SBP and worse LV diastolic function. These results highlight the importance of BP reduction in the treatment of CKD.

Two-dimensional longitudinal strains and torsion analysis to assess the protective effects of ischemic postconditioning on myocardial function: A speckle tracking echocardiography study in rabbits

The reperfusion injury that occurs in the early reperfusion often results in myocardial dysfunction. This study evaluated global and regional left ventricular (LV) function using speckle tracking echocardiography (STE) in a rabbit ischemia–reperfusion (I/R) model with and without ischemic postconditioning (I-PostC). The aim is to investigate the potential benefit of I-PostC for myocardial function and validate whether regional longitudinal strain is an appropriate index to indicate myocardial dysfunction. Forty rabbits were divided into an ischemia–reperfusion group (group I) and an I-PostC group (group II). After the coronary arteries were ligated, LV systolic strain and twist parameters decreased, and absolute value of strain rate of isovolumetric relaxation period (SRivr) and post-systolic strain index (PSI) increased significantly in both groups (all p<0.05). After reperfusion, regional longitudinal systolic strain rate (SRsys), systolic strain (Ssys), LV twist and untwisting rate increased, and SRivr and PSI decreased in group II. These changes were not seen in group I. All STE parameters were correlated with area of necrosis (AN)/area at risk (AR) (all p<0.05). The correlations were morerelevant between SRsys and AN/AR (r=−0.673) and between Ssys and AN/AR (r=−0.777) (both p<0.001). The intra- and inter-observer repeatability of STE parameters were good with correlation coefficients (CCs) >0.8 or 0.6. The sensitivities of GSRsys, GSsys, SRsys, Ssys, and LV twist to detect the myocardial infarction were 81.3%, 62.5%, 87.5%, 93.8% and 81.3%, respectively. And the specificities of those parameters were 75.0%, 81.2%, 75.0%, 87.5% and 68.7%. These results indicate that STE is useful for quantitative detection on myocardial function improvement induced by I-PostC in a rabbit I/R model. The regional index—Ssys is an appropriate parameter to indicate myocardial dysfunction because of its sensitivity, specificity, and repeatability.

Effects of age on left ventricular twist-displacement loop assessed by velocity vector imaging

To assess effect of age on the characteristic of left ventricular (LV) twist-displacement loop in health volunteers by velocity vector imaging (VVI) and to provide a new method for LV function evaluation in clinic. After obtaining basal and apical LV short-axis images in 98 healthy volunteers (18-75 years old) by 2-dimensional echocardiography, we use VVI software to analysis LV twist motion and radial displacement at each plane off-line. The peak LV twist (Ptw), the peak untwist velocity (PutwV), the proportion of untwist in isovolumetric relaxation period (Iutw%) and LV radial displacement (Dis) were measured and calculated. Then we constructed LV twist-displacement loop and compared the characteristic of them among different groups. Ptw increased gradually with the increase in age. The biggest PutwV was in the group of 30-60 years old. Iutw% increased gradually before 60 years old, then decreased after that. Dis was not obviously different among the three groups. The characteristic of LV twist-displacement loop was like the configuration of 8. There was a linear relation between twist and displacement during systole, and the slope increased gradually with the increase in age. During early diastole, the relatively small radial expanding displacement displayed with untwisting, resulting in a much steeper twist-displacement relationship curve occurred in each group, which was getting smooth gradually when the radial expanding displacement increased during mid to late diastole. VVI can be used to effectively and noninvasively assess LV twist-displacement loop with change in age and provide important information for LV function. The effect of age must take into account when evaluate the LV function by the twist-displacement loop.

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Cardiac Dysfunction and Prolonged Hemodynamic Deterioration After Implantable Cardioverter-Defibrillator Shock in Patients With Systolic Heart Failure

We investigated the acute effects of implantable cardioverter-defibrillator shock on myocardium, cardiac function, and hemodynamics in relation to left ventricular systolic function. We studied 50 patients who underwent implantable cardioverter-defibrillator implantation and defibrillation threshold (DFT) testing: 25 patients with left ventricular ejection fraction (LVEF) ≥ 45% and 25 patients with LVEF <45%. We measured cardiac biomarkers (creatine kinase, creatine kinase-MB, myoglobin, cardiac troponin T and I, and N-terminal probrain natriuretic peptide). Left ventricular relaxation was assessed by global longitudinal strain rate during the isovolumetric relaxation period using speckle-tracking echocardiography. Blood sampling and echocardiography were performed before, immediately after, and 5 minutes and 4 hours after DFT testing. Mean arterial pressure was measured directly during DFT testing. Cardiac biomarkers showed no significant changes in either group. LVEF was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in the group with reduced LVEF (P<0.001), whereas LVEF reduction was not observed in the group with preserved LVEF (P=0.637). Global isovolumetric relaxation period was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in both groups (preserved LVEF: 0.39 ± 0.14 versus 0.23 ± 0.13* versus 0.23 ± 0.13* versus 0.40 ± 0.13 s(-1), *P<0.001 versus baseline; reduced LVEF: 0.15 ± 0.05 versus 0.08 ± 0.04† versus 0.09 ± 0.04† versus 0.15 ± 0.05 s(-1), †P<0.001 versus baseline, repeated-measures ANOVA). Time to recovery of mean arterial pressure to the baseline was prolonged in the group with reduced LVEF (P<0.001). Implantable cardioverter-defibrillator shock transiently impairs cardiac function and hemodynamics especially in patients with systolic dysfunction, although significant tissue injury is not observed.

Differentiation Between Fresh and Old Left Ventricular Thrombi by Deformation Imaging

Noninvasive echocardiographic differentiation between old and fresh left ventricular thrombi after myocardial infarction would be of clinical importance to estimate the risk for embolization and the necessity of anticoagulation. Fifty-two patients, aged 41 to 87 years, with a thrombus after myocardial infarction were included in this 2-part study: In substudy-I, 20 patients, 10 each with a definite diagnosis of fresh or old thrombus, were included. In the subsequent prospective substudy-II, 32 consecutive patients with an incident thrombus after myocardial infarction but unknown thrombus age were started on phenprocoumon and followed for 6 months. Data on medical history, standard echocardiography, strain-rate (SR) imaging and magnetic resonance tomography were analyzed. In substudy-I, analysis of thrombus deformation revealed the most rapid change in SR during the isovolumetric relaxation period when cavity pressure decreases rapidly. Fresh (range: 5-27 days) and old thrombi (4-26 months) could be discriminated without overlap by peak SR during the isovolumetric relaxation period, using a cutoff value of 1 s(-1). Applying this threshold value in substudy-II, 17 thrombi were echocardiographically classified as fresh (=SR ≥1 s(-1)) and 15 as old. After 6 months in the fresh thrombus group, 16 of 17 thrombi had disappeared (94%), and in 1 patient the thrombus size was diminished by >50% (now presenting an old thrombus SR pattern). In contrast, 14 of the 15 old thrombi remained unchanged in size and deformation (1 thrombus disappeared). Fresh and old intracavitary thrombi can be reliably differentiated by deformation imaging. In fresh thrombi, anticoagulation with phenprocoumon results in thrombus resolution in most patients.

111 “New” echocardiographic isovolumetric parameters combined with standard parameters for the assessment of left ventricular filling pressures

Left ventricular filling pressures’ evaluation is still challenging. The ratio of the transmitral and myocardial early diastolic velocities (E/E’) can be used to estimate LV filling pressures (LVFP), but between 8 and 15 it remains unclear. Additionally, the time difference between the onset of E and E’ (Δ (RE-E’)), the time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity (Δ (IVRT-IVRT’)) and the mitral early diastolic velocity (E)/Strain rate ratio during the isovolumetric relaxation period also correlate to LVFP. The aim of this study was to evaluate the incremental value of those indices to evaluate LVFP (as measured by left ventricular end diastolic pressure (LVEDP)) in a heterogeneous group of patients during a simultaneous invasive procedure. Simultaneous cardiac catheterization, BNP dosage and doppler echocardiography were performed in 30 patients. LVEDP was elevated (>16 mm Hg) in 14 patients (46,7%). The 3 previously described “new” parameters are significantly correlated to LVEDP, but particularly highly significant correlation was found between Δ (IVRT-IVRT’) and LVEDP (r = −0,74, p < 0,005). ROC curves predict a 80% sensibility and specificity of Δ (IVRT-IVRT’). Δ (RE-E’) sensibility and specificity at lateral site are 87% and 93% respectively. E/SRivr has a 71% sensibility and a specificity. The incremental diagnostic value of each parameter and BNP in combination with “classic” parameters (E/A, E/E’) was evaluated by kappa coefficient. Δ (IVRT-IVRT’) at septal site (k = 0,777) and Δ (RE-E’) (k = 0,73) are the most accurate parameters, whereas additional use of E/SRivr (k = 0,41) isn’t more useful than “classic” echocardiographic strategy (k = 0,478) such as BNP (k = 0,533). Δ (IVRT-IVRT’) and Δ (RE-E’) can predict LV filling pressures with reasonable accuracy.

The Timing of Onset of Mechanical Systole and Diastole in Reference to the QRS-T Complex: a Study to Determine Performance Criteria for a Non-Invasive Diastolic Timed Vibration Massage System in Treatment of Potentially Unstable Cardiac Disorders

Our institution is in development of a low frequency, non-invasive Diastolic Timed Vibrator (DTV) for use in emergency treatment of ST Elevation Myocardial Infarction (STEMI). It is preferable to avoid vibration emissions during the IsoVolumetric Contraction Period (IVCP) and at least the majority of mechanical systole thereafter, as systolic vibration may cause a negative inotropic effect in the ischemic heart. Furthermore diastolic vibration should preferably include the IsoVolumetric Relaxation Period (IVRP) which has been shown in clinical studies to improve cardiac performance and enhance coronary flow. Electrocardiographic (ECG) monitoring can be used to enable diastolic tracking, however, the timing of the phases of the cardiac cycle in relation to the ECG waveform must first be verified. The objective of this study was therefore to determine timing of onset of mechanical systole and diastole in reference to the QRS-T Complex. One hundred and twenty-three adult echocardiographic studies were assessed for the point of mitral and aortic valve closure in relation to the QRS complex and T wave in a representative population. We found that onset of mechanical systole occurred on and usually shortly after the peak of a first dominant QRS complex deflection, and onset of diastole occurred at the earliest on and most commonly beyond the peak or midpoint of the T wave. A DTV should ideally be able to stop vibrating on or before the peak of the first dominant deflection of a QRS complex, and begin vibrating near the peak of the T wave. Given early detection of ventricular depolarization can occur 10-20ms prior to R wave peak, it is proposed that a DTV should preferably be able to stop vibrating within 10ms of a triggered stop command. Onset of vibration during peak of T wave could be approximated by a rate adapted Q-T interval regression equation, and then fine tuned by manual adjustment during therapy.

Abstract 4725: Left Ventricular Myocardium Shows Base-to-Apex Deformation Gradient during Isovolumic Relaxation Period in Healthy Subjects

Introduction: Deformation of LV myocardium during isovolumetric relaxation period (IVR) is not well described. Methods: We performed echocardiography (Vivid 7, GE Medical) in 90 healthy subjects at rest (mean age 38 ±13 years, 34 males). Standard long and short LV axis views were acquired with high frame rate (65–100 fps) and used for strain rate (Sr) measurement by speckle tracking (EchoPac PC) in three directions: longitudinal (SrL), circumferential (SrC) and radial (SrR). Segmental Sr curves were the average Sr in each LV levels, i.e. base (B), mid (M) and apex (A) and normalized by R-R interval duration (Panel A and B). We then calculated Sr gradients during IVR as maximal instantaneous difference between apex-to-base or mid-to-base LV Sr (Sr(A-B) or Sr(M-B), Panel C). Pulsed wave Doppler flow profiles were used to determine cardiac intervals. Results: SrL(A-B), SrC(A-B) and SrR(A-B) were 0.53 ±0.43, 0.67 ±0.46, −1.89± 1.52 s-1. SrL(M-B), SrC(M-B) and SrR(M-B) were 0.37±0.15, 0.5±0.34 and −2.14±1.4 s-1. Both types of gradient were identified for all strains (p&lt;0.001 vs. zero), and were also different from each other (p&lt;0.001, Sr(A-B) vs. Sr (M-B) for similar strain). The gradients were driven by faster relaxation in apical and mid LV segment and brief shortening in basal segment (see Figure inset). Conclusions: Differential deformation of LV exists during IVR. This deformation difference in the base to apex direction may facilitate changes in LV geometry that result in rapid intra-cavitary pressure reduction.

A New Parameter of Pulsed‐Wave Tissue Doppler Imaging: IVRa

We investigated how velocity of isovolumetric relaxation period on pulsed-wave tissue Doppler trace (IVRa and IVRb) is affected by the left ventricular (LV) geometry changes. Two hundred cases without exclusion criteria were included in the study. Normal LV mass index (LVMI) and normal relative wall thickness (RWT) was assigned to group 1 (n = 72). Concentric remodeling (normal LVMI and increased RWT) was defined to group 2 (n = 25). Eccentric LV hypertrophy (LVH) (increased LVMI and normal RWT) was defined to group 3 (n = 62). And finally, concentric LVH (increased LVMI and increased RWT) was defined to group 4 (n = 41). Patients with LVH (groups 3 and 4) were older than group 1 (P = 0.017 and 0.001). It was observed in the assessment of M-mode ECHO parameters that the aortic valve diameter, aortic valve opening, LV end-systolic diameter (LVESD), LV end-diastolic diameter (LVEDD), and left atrium (LA) were higher in cases with eccentric LVH. It was shown that Ea velocity and Sa velocity time integral (Sa-VTI) were decreased with LV geometry change. However, IVRa velocity and E/Ea were increased as LV geometry change. A positive correlation between IVRa velocity and LVMI (correlation ratio = 34%, P = 0.000) was found. Similarly, a positive correlation between IVRa velocity and RWT (correlation ratio = 17%, P = 0.025) was found. IVRa velocity exhibits a positive correlation with LV geometry changes indicating that IVRa velocity is affected by LV geometry like the other parameters influenced by LV geometry.

Response to Letter by Weidemann et al Regarding Article, “Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressure”

We thank Weidemann et al for their interest in our study.1 We hereby address their comments. They mistakenly state that we “had some difficulties in patients with wall motion abnormalities”. We are surprised at this comment, as we clearly show that the ratio of E to strain rate in the isovolumetric relaxation period (SRIVR) was significantly related to mean wedge pressure in patients with regional dysfunction ( r =0.83, P <0.01) and performed better than the E/Ea ratio ( r =0.63, P <0.01).1 The ratio of E/SRIVR accurately identified patients with regional …

Letter by Weidemann et al Regarding Article, “Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressure”

HomeCirculationVol. 116, No. 14Letter by Weidemann et al Regarding Article, “Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressure” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter by Weidemann et al Regarding Article, “Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressure” Frank Weidemann and Joerg M. Strotmann Bart Bijnens Frank WeidemannFrank Weidemann Department of Internal Medicine I, University Hospital Wuerzburg, Germany Search for more papers by this author and Joerg M. StrotmannJoerg M. Strotmann Department of Internal Medicine I, University Hospital Wuerzburg, Germany Search for more papers by this author Bart BijnensBart Bijnens Medical School and Faculty of Electronic Engineering, University of Zagreb, Croatia Search for more papers by this author Originally published2 Oct 2007https://doi.org/10.1161/CIRCULATIONAHA.107.708784Circulation. 2007;116:e368To the Editor:We have read with interest the paper by Wang et al1 on diastolic function assessed by strain rate in the isovolumetric relaxation period (SRIVR) derived from 2-dimensional speckle tracking. In principle, 2-dimensional speckle tracking is a useful progression toward an automated assessment of left ventricular deformation.We would like to comment on the fact that the authors had some difficulties with patients with wall motion abnormalities. It is known from many studies that different conditions such as acute ischemia, regional fibrosis, and increased afterload result in ongoing (postsystolic) deformation during isovolumic relaxation (IVR).2,3 This deformation will change local SRIVR independently from tau, which thus limits the assessment of diastolic function by analysis of SRIVR in a wide range of important clinical conditions.In addition, we agree that E/Ea has some limitations when diastolic function is assessed, especially in the gray zone between 8 and 15. However, although it has merits in the assessment of strain, we think that 2-dimensional speckle tracking is not satisfactory when strain rate is assessed, especially during IVR. It is well known that speckle tracking can only be performed at relatively low frame rates. However, this low frame rate prevents resolution of the fast change in deformation (ie, strain rate) that occurs during IVR. This lack of resolution leads, as correctly mentioned in the paper,1 to an underestimation of peak strain-rate value. Thus, we would suggest use of Doppler-derived strain rate (with its high temporal resolution), and not speckle tracking strain rate, to accurately assess SRIVR.The authors could nicely show the limitations of diastolic function assessment by pulsed-wave tissue Doppler imaging and suggest a greater focus on diastolic deformation. However, we believe that assessment of strain rate during IVR with 2-dimensional speckle tracking and its inherent technical limitations will prove a real challenge in clinical conditions.DisclosuresNone.1 Wang J, Khoury DS, Thohan V, Torre-Amione G, Nagueh SF. Global diastolic strain rate for the assessment of left ventricular relaxation and filling pressures. Circulation. 2007; 115: 1376–1383.LinkGoogle Scholar2 Weidemann F, Dommke C, Bijnens B, Claus P, D’hooge J, Mertens P, Verbeken E, Maes A, Van de Werf F, De Scheerder I, Sutherland GR. Defining the transmurality of a chronic myocardial infarction by ultrasonic strain-rate imaging: implications for identifying intramural viability: an experimental study. Circulation. 2003; 107: 883–888.LinkGoogle Scholar3 Voigt JU, Lindenmeier G, Exner B, Regenfus M, Werner D, Reulbach U, Nixdorff U, Flachskampf FA, Daniel WG. Incidence and characteristics of segmental postsystolic longitudinal shortening in normal, acutely ischemic, and scarred myocardium. J Am Soc Echocardiogr. 2003; 16: 415–423.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Chiang S, Daimon M, Ishii K, Kawata T, Miyazaki S, Hirose K, Ichikawa R, Miyauchi K, Yeh M, Chang N and Daida H (2014) Assessment of Elevation of and Rapid Change in Left Ventricular Filling Pressure Using a Novel Global Strain Imaging Diastolic Index, Circulation Journal, 10.1253/circj.CJ-13-0513, 78:2, (419-427), . October 2, 2007Vol 116, Issue 14 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCULATIONAHA.107.708784PMID: 17909112 Originally publishedOctober 2, 2007 PDF download Advertisement SubjectsEchocardiography

Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressures

Diastolic strain rate (SR) measurements that comprise all left ventricular (LV) segments are advantageous over myocardial velocity for assessment of diastolic function. Mitral early diastolic velocity (E)/SR ratio during the isovolumetric relaxation (IVR) period can be used to estimate LV filling pressures. Simultaneous echocardiographic imaging and LV pressure measurements (7F catheters) were performed in 7 adult dogs. Loading conditions were altered by saline infusion and caval occlusion, and lusitropic state was changed by dobutamine and esmolol infusion. A curve depicting global SR was derived from each of the 3 apical views, and SR was measured during IVR (SR(IVR)) and early LV filling (SR(E)). SR(IVR) had a strong correlation with time constant of LV pressure decay during the IVR period (tau) (r=-0.83, P<0.001), whereas SR(E) was significantly related to LV end-diastolic pressure (r=0.52, P=0.005) in the experimental stages where tau was <40 ms. In 50 patients with simultaneous right heart catheterization and echocardiographic imaging, mitral E/SR(IVR) ratio had the best correlation with mean wedge pressure (r=0.79, P<0.001), as well as in 24 prospective patients (r=0.84, P=0.001). E/SR(IVR) was most useful in patients with ratio of E to mitral annulus early diastolic velocity (E/Ea ratio) 8 to 15 and was more accurate than E/Ea in patients with normal ejection fraction and regional dysfunction (both P<0.01). Global SR(IVR) by 2-dimensional speckle tracking is strongly dependent on LV relaxation. E/SR(IVR) can predict LV filling pressures with reasonable accuracy, particularly in patients with normal ejection fraction and in those with regional dysfunction.

How to distinguish between ischemic and nonischemic postsystolic thickening: A strain rate imaging study

Ongoing myocardial thickening after aortic valve closure (postsystolic thickening = ε PST) is an established marker for the presence of segmental ischemia. However, ε PST may also be present in late activated segments and can be induced by pharmacological interventions or left ventricular pressure overload. The aim of this study was to determine if it is possible to distinguish between ischemic and nonischemic ε PST. In an experimental pig-model ( n = 11) regional radial deformation was measured in the inferolateral wall during either normal perfusion or regional ischemia using ultrasonic strain rate imaging. Ischemia was induced by active hypoperfusion of the circumflex coronary artery territory. Measurements were made at 1. baseline, and during 2. theodrenalin infusion, 3. dobutamine infusion 4. esmolol infusion and 5. during a preload increase induced by saline infusion. In all segments where thickening was ongoing after aortic valve closure, the amount of ε PST was calculated as the difference of maximal strain minus systolic strain. In addition, peak strain rate during the isovolumetric relaxation period was extracted. During normal coronary perfusion, 73% of all segments ( n = 40) developed ε PST. This physiological ε PST averaged 5 ± 2% and was most frequently induced during the esmolol infusion ( n = 11). Peak isovolumetric strain rate averaged −2.1 ± 0.5 s −1 in segments with physiological ε PST. During coronary hypoperfusion, 96% of the “at risk” segments developed ε PST. ε PST in the ischemic segments averaged 14 ± 3%, and was highest during the dobutamine infusion (25 ± 4%) and lowest during the esmolol infusion (5 ± 1%). In contrast to normally perfused segments, peak isovolumetric strain rate was positive in the ischemic segments and averaged 2.0 ± 0.5 s −1 in these pathologic segments with postsystolic strain. Using a cut-off value of ≥ 0 s −1 for isovolumetric strain rate, pathologic ε PST was detected with a sensitivity of 100% and a specificity of 87%. These experimental findings were confirmed by a subsequent clinical study with 6 patients with acute myocardial infarction (ischemic group) and 6 patients with arterial hypertension or aortic stenosis (nonischemic group). Ischemic and nonischemic postsystolic thickening can be precisely differentiated by extracting the polarity of the peak isovolumetric strain curve. (E-mail: strotmann_j@medizin.uni-wuerzburg.de)