Left Ventricular Lateral Wall Research Articles

Simplified apical four-chamber view evaluation of relative apical sparing of longitudinal strain in diagnosing AL amyloid cardiomyopathy.

To assess the diagnostic utility of a simplified approach to relative apical sparing of longitudinal strain (RAS LS) using only an apical four-chamber view (A4C) in patients with AL amyloid cardiomyopathy (ALAC). We retrospectively evaluated echocardiographic recordings of 20 patients with ALAC, 20 patients with Fabry disease-related cardiomyopathy (FD), and 20 patients with concentric hypertensive left ventricular hypertrophy (HLVH) matched for mean LV mean thickness. Peak segmental LS values of the interventricular septum and lateral LV wall were measured in the A4C using two-dimensional speckle-tracking echocardiography. RAS LS was calculated as average apical LS/(average basal LS+average midventricular LS). Relative apical sparing of longitudinal strain values in patients with ALAC (1.23±0.64) were significantly higher than those in FD patients (0.75±0.19, P<0.05) as well as in individuals with HLVH (0.75±0.23, P<0.05), but with a significant overlap. The optimal RAS LS value differentiating ALAC from FD and HLVH with 70% sensitivity and 75% specificity was 0.88 (AUC 0.79). In multivariate modeling, RAS LS was significantly additive to traditional predictors of ALAC (low QRS voltage and pseudoinfarct ECG patterns, pericardial effusion, E/e' ratio, E-wave deceleration time; P<0.05 for all models). Simplified RAS LS evaluation represents an attractive approach for diagnostics of ALAC. However, because of considerable overlap with other disorders with hypertrophic phenotype, the analysis of RAS LS in the A4C should be combined with other traditional echocardiographic and ECG predictors in differentiating ALAC from other forms of concentric LV wall thickening.

Speckle Tracking of the Basal Lateral and Septal Wall Annular Plane Systolic Excursion of the Right and Left Ventricles of the Fetal Heart.

Annular plane systolic excursion (APSE) has been evaluated for the right (RV) and left (LV) ventricles using M-mode echocardiography. This study examined APSE using 2-dimensional speckle tracking (2DST) of the lateral and septal annuli of the RV and LV in normal fetuses. Two hundred normal fetuses were prospectively examined between 20 and 40 weeks' gestation, in which the end-diastolic and end-systolic lengths were measured from the apex to the insertion of the annuli into the lateral and septal walls of the RV and LV using 2DST. Subtracting the end-systolic from the end-diastolic length resulted in the APSE measurement. The APSE values from the ventricular and septal locations were regressed against biometric and gestational age independent variables, and the mean and standard deviation computed using fractional polynomial analysis. Within-subject repeated measures of variance were used to compare results within and between the right ventricular and left ventricular basal APSE values. When regressed against the independent variables the R2 for the APSE of the right ventricular lateral wall ranged from 0.39 to 0.40, the left ventricular lateral wall 0.29 to 0.31, the right ventricular septal wall 0.22 to 0.40, and the left ventricular septal wall 0.05 to 0.07. There was a significant difference (P < .001) for APSE between the right ventricular and left ventricular lateral wall and their respective septal annuli, the left ventricular and right ventricular lateral wall annuli, and the left ventricular and right ventricular septal annuli. The right ventricular and left ventricular lateral and septal wall APSE can be computed using 2DST and are associated with changing fetal biometric and age measurements.

Left ventricle primary cardiac fibroma in an adult: A case report.

There is a very low prevalence of cardiac fibroma in the adult population. Cardiac fibromas arise from heart fibroblasts, and these tumors are primarily located in the ventricles or in the interventricular septum. Symptomatic tumors are treated by resection. By contrast, asymptomatic tumors require a long-term follow-up or surgical resection as a preventive measure to avoid complications. The present study reports the case of a 43-year-old man, who presented with a cough and shortness of breath for 2 months. Echocardiogram and cardiac magnetic resonance imaging indicated a large mass located in the left ventricular lateral wall. The patient underwent surgical excision of the tumor, and histopathological examination confirmed the mass to be a fibroma. The patient had a good postoperative recovery and was discharged on day 9 post-surgery.

P3739Septal rebound stretch is a tug of war between septum and left ventricular lateral wall

P3739Septal rebound stretch is a tug of war between septum and left ventricular lateral wall

P5660Reduced left ventricular lateral wall contractility leads to recovery of septal function in left bundle branch block

P5660Reduced left ventricular lateral wall contractility leads to recovery of septal function in left bundle branch block

Native T1 and T2 mapping by cardiovascular magnetic resonance imaging in pressure overloaded left and right heart diseases.

Pulmonary arterial hypertension (PAH) and severe aortic valve stenosis (AS) are diseases characterized by increased afterload of the right and left heart, respectively. Our study aims to investigate the differences of myocardial tissue characteristics in the pressure overloaded left and right hearts, especially in the shared interventricular septum, as detected by native T1 and T2 relaxation times. Eighteen patients with PAH and 19 patients with severe AS in addition to 5 healthy volunteers underwent 1.5-T CMR examination with native T1 and T2 mapping. Mean T1 and T2 value were measured at the right ventricular (RV) free wall, superior RV insertion, inferior RV insertion, interventricular septum and left ventricular (LV) lateral wall. Compared with controls and AS group, T1 was significantly elevated in the RV insertion in PAH group (P=0.015), while no statistically significant differences were seen in other segments among the three groups. There was an increase of T2 in the RV insertion in AS and PAH groups (P=0.01). Significant T2 elevation was also observed in the RV free wall of PAH group, and the LV lateral wall of AS group compared with the control group. RV insertion T2 was significantly correlated with RV end-diastolic volume index (r=0.608, P=0.016) and RV mass index (r=0.57, P=0.026) in the PAH group. LV lateral wall T2 and RV insertion T2 were significantly correlated with aortic valve mean gradients in the AS group (r=0.56, P=0.02; r=0.58, P=0.01, respectively). In pressure overload diseases, both T1 and T2 values increase in the myocardium. The alterations seen in the RV insertion sites in the septum was more pronounced with RV pressure overload. T2 values also correlated with structural and functional remodeling in both diseases. Combining T1 and T2 mapping may help to better characterize the alternation of myocardial composition in pressure overloaded heart diseases.

Dynamic Myocardial Response to Exercise in Childhood Cancer Survivors Treated with Anthracyclines

Anthracycline cardiotoxicity can cause significant long-term morbidity in childhood cancer survivors (CCS), but many CCS do not manifest clinical symptoms until adulthood. The aims of this study were to characterize the dynamic myocardial response to exercise of CCS at long-term follow-up by combining semisupine bicycle exercise stress echocardiography with myocardial imaging techniques and to establish whether semisupine bicycle exercise stress echocardiography could identify CCS with abnormal exercise response. This was a single-center prospective cross-sectional study. One hundred CCS and 51 control subjects underwent semisupine bicycle exercise stress echocardiography. Color Doppler tissue imaging peak systolic (s') and diastolic (e') velocities, myocardial acceleration during isovolumic contraction, and longitudinal strain were measured at rest and at incremental heart rates in the left ventricular (LV) lateral wall, basal septum, and right ventricle. The relationship with increasing heart rate was evaluated for each parameter by plotting the values against heart rate at each stage of exercise. Kernel density estimate was used to establish the normality of the individual CCS exercise responses. At rest, no significant differences were found for LV lateral wall, right ventricular (RV), and basal septal systolic and diastolic velocities between CCS and control subjects. Only septal e' was lower in CCS. LV longitudinal strain was similar between groups, while RV longitudinal strain was lower in CCS. At peak exercise, LV lateral wall, RV, and septal s' were not different between groups, while e' were significantly lower in CCS. LV lateral wall and septal isovolumic acceleration were also reduced in CCS. LV longitudinal strain was different between groups, while RV longitudinal strain was similar. The dynamic response of Doppler tissue imaging velocities, isovolumic acceleration, and strain was similar between CCS and control subjects. Kernel density estimate analysis confirmed that most CCS responses were within the normal range. At 10-year follow-up, anthracycline-treated CCS with normal baseline ejection fractions have LV and RV systolic and diastolic myocardial exercise response comparable with that of control subjects. Minor differences were observed between CCS and control subjects at rest and at peak exercise, but the dynamic response is within the normal range.

Apical Transverse Motion Is Associated with Interventricular Mechanical Delay and Decreased Left Ventricular Function in Children with Dilated Cardiomyopathy

Apical transverse motion (ATM) is associated with electromechanical dyssynchrony in adult dilated cardiomyopathy (DCM). Bundle branch block electromechanical dyssynchrony is uncommon in pediatric DCM, but ATM and its association with ventricular function have not been characterized. Fifty-six children with DCM were retrospectively studied. Using echocardiography, ATM was assessed visually and by speckle-tracking longitudinal displacement of the interventricular septal and left ventricular (LV) lateral walls in opposite directions. Doppler tissue imaging-derived displacement and velocities were used to time the onset and peak LV and right ventricle motion, from which intra- and interventricular delays were calculated to assess their association with ATM. The timing of aortic valve opening and closure in relation to onset and peak LV displacement was used as a measure of LV mechanical efficiency. LV ATM was observed in 35 of 56 patients (62.5%), occurring in two patterns: 45% had ATM (interventricular septum displacing toward the lateral wall and lateral wall displacing toward the mitral annulus during systole), and 18% showed reverse ATM (r-ATM; lateral wall displaced toward the apex and interventricular septum displaced toward the septal annulus during systole). Both patterns were associated with increased interventricular but not intraventricular mechanical delay (controls: 2 msec, ATM 16 msec, r-ATM 8 msec, both P<.05 vs control subjects). Patients with ATM or r-ATM had lower LV ejection fractions (19% vs 29%, P<.05) and higher mechanical inefficiency compared with those without ATM. Survival was not statistically different in those with ATM or r-ATM compared with those without ATM or r-ATM. In pediatric DCM, ATM is associated with LV dysfunction, mechanical inefficiency, and interventricular mechanical delay.

Afterload Hypersensitivity in Patients With Left Bundle Branch Block

ObjectivesThis study sought to investigate the hypothesis that patients with left bundle branch block (LBBB) are hypersensitive to elevated afterload. BackgroundEpidemiological data suggest that LBBB can provoke heart failure in patients with hypertension. MethodsIn 11 asymptomatic patients with isolated LBBB and 11 age-matched control subjects, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured by echocardiography. Systolic arterial pressure was increased by combining pneumatic extremity constrictors and handgrip exercise. To obtain more insight into mechanisms of afterload response, 8 anesthetized dogs with left ventricular (LV) micromanometer and dimension crystals were studied during acutely induced LBBB and aortic constriction. Regional myocardial work was assessed by LV pressure-dimension analysis. ResultsConsistent with normal afterload dependency, elevation of systolic arterial pressure by 38 ± 12 mm Hg moderately reduced LVEF from 60 ± 4% to 54 ± 6% (p < 0.01) in control subjects. In LBBB patients, however, a similar blood pressure increase caused substantially larger reduction in LVEF (p < 0.01), from 56 ± 6% to 42 ± 7% (p < 0.01). There were similar findings for GLS. In the dog model, aortic constriction abolished septal shortening (p < 0.02), and septal work decreased to negative values (p < 0.01). Therefore, during elevated systolic pressure, the septum made no contribution to global LV work, as indicated by net negative work, and instead absorbed energy from work done by the LV lateral wall. ConclusionsModerate elevation of arterial pressure caused marked reductions in LVEF and GLS in patients with LBBB. This reflects a cardiodepressive effect of elevated afterload in the dyssynchronous ventricle and was attributed to loss of septal function.

A Rare Case of Single Right Coronary Artery with Absent Left Main Coronary Artery

A 54-year-old woman presented with abdominal pain and diarrhoea, and had new T-wave inversion on electrocardiogram in leads V2–V6. Past history included recurrent deep vein thrombosis/pulmonary embolism and a recent subtotal colectomy for ulcerative colitis. The patient denied chest pain and serial troponin I measurements were normal (<0.040 μg/L). Postoperative ileus was the likely cause of abdominal pain. Echocardiography revealed impaired left ventricular (LV) systolic function (LV ejection fraction 35–40%). Coronary angiography was performed and the left main coronary artery (LMCA) could not be located despite cuspal injections, ascending aortogram, and left ventriculogram. A dominant right coronary artery (RCA) was visualised, which passed around the left ventricular apex to the area normally supplied by the obtuse marginal, diagonal, and distal left anterior descending arteries. Computed tomography coronary angiography (CTCA) revealed a superdominant RCA supplying the LV apex and lateral wall with no LMCA coming off the left coronary cusp. The left circumflex was small and arose from a conus branch separate to the RCA. No significant stenosis was visualised on CTCA. The T-wave changes on electrocardiogram and subtle subendocardial enhancement/fibrosis in the anterior wall on cardiac magnetic resonance imaging were deemed to be secondary to supply–demand ischaemia, particularly at the distal end of the RCA, where it supplied the left anterior descending artery territory. The patient was discharged on metoprolol 25 mg twice daily and her usual warfarin. Single RCA with absent LMCA is extremely rare with only few isolated cases in the literature. Use of CTCA in combination with coronary angiography was useful in defining this unusual anatomy.

Role of CT and MRI in Diagnosis of Pericardial Diseases

Background: Pericardial disease is an important cause of morbidity and mortality in patients with cardiovascular disease. Although the pericardium is usually sufficiently thick to be identified on CCT and CMR, visualization at the most common site of pericardial defects, the lateral, posterior, and inferior left ventricular wall, can be poor because of a paucity of fat. Objective: The aim of this study was to evaluate the role of CT & MRI in the diagnosis of pericardial diseases. Patients and Methods: 30 patients with cardiac abnormalities were included. All patients’ data of preoperative were reported. Range of age was 15-59 years. 20 patients were male and 10 patients were female. Results: In our study MR imaging showed accuracy of 93% for differentiation between constrictive pericarditis and restrictive cardiomyopathy on the basis of depiction of thickened pericardium. In our study on MR images, an intact pericardial line may be observed if an adjacent tumor extends to the pericardium but not through it. Tumors that have invaded the pericardium may be recognized by focal obliteration of the pericardial line and the presence of pericardial effusion. Hemorrhagic pericardial effusions secondary to metastases usually have high signal intensity on SE images. Conclusion: CT and MR imaging should be used when findings at echocardiography are difficult to interpret or conflict with clinical findings.

Postnatal myocardium remodelling generates inhomogeneity in the architecture of the ventricular mass

BackgroundThe 3D architecture of the ventricular mass is poorly known, although in vivo imaging techniques show the physiological inhomogeneity of ventricular walls mechanics. Polarized light imaging makes it possible to quantitatively analyse the myosin filament orientation.AimsIn this paper, we focus on the study the 3D architecture and regional isotropy of myocardial cells.MethodsTwenty normal human hearts, 10 from the perinatal period and 10 from the post-neonatal period were studied by polarized light microscopy. In each voxel of the ventricular mass (90 × 90 × 500 µm) the principal orientation segment was automatically and unambiguously extracted as well as a regional isotropy index (regional orientation tensor of the voxel neighbourhood).ResultsDuring the first months of postnatal age, the median regional isotropy values decreased in the ventricular mesh. This global decrease was not homogeneous across the ventricular walls. From the perinatal to the neonatal period, this decrease was more marked in the inner two-third of the lateral left ventricular wall and in the right part of the interventricular septum. There was a progressive post-neonatal appearance of a particularly inhomogeneous secondary arrangement of myocardial cells with alternation of thick low-RI and thin high-RI areas.ConclusionsThis study has shown a postnatal change in ventricular myocardial architecture, which became more inhomogeneous. The cell rearrangements responsible for the inhomogeneity in ventricular myocardial architecture are revealed by a variation of the regional isotropy index. These major changes are probably an adaptive consequence of the major haemodynamic changes occurring after birth during the neonatal period that generates major parietal stress variations and parietal remodelling.

Abstract 21067: Improvements in Regional Myocardial Function on 2D STE With Optimized Chelation in Patients With Thalassemia Major (TM)

Intro: Thalassemia Major (TM) is characterized by recurrent blood transfusions leading to myocardial siderosis and complications including arrhythmias and heart failure. These can be reversible with adequate chelation. We explored the effect of improved chelation and subsequent cardiac T2* MRI (CMR) values on regional myocardial function assessed by 2D STE in setting of normal LVEF. Methods: Data was derived from TM patients recruited for the AMIT study (efficacy of amlodipine with chelation in reducing myocardial iron). All patients underwent echocardiographic imaging at baseline, 6 and 12 months. LSsys was extracted from basal, mid, and apical segments of the LV medial and lateral wall by 2D STE technique. A linear regression model was run to determine the effect of improved T2* in the setting of improved chelation on regional LSsys strain parameters. Results: Nineteen TM patients (11 males), median age 16 (8-21) yrs. All participants were transfused every 2-3 weeks. (median pre-transfusional Hb of 9.3 (8.3-10.8) mg/dL). T2* based chelation regimen was initiated at baseline and compliance to this regimen was gauged at regular clinical visits. 25 data points were available from interval 2D STE imaging for analysis. Medial basal LSsys (-17.3% ± 2.2) and lateral basal LSsys (-16.7% ± 4.4) strains were significantly lower than mean apical LSsys strains (-24.9% ± 4.0) (p &lt;0.01). With optimized improved chelation, we determined up to a 6.3% improvement was seen in LSsys basal septal and 6.7% improvement in LSsys apical septal for each 1 ms improvement in T2* (p values &lt; 0.05). Conclusion: 2D STE can help identify regional myocardial dysfunction prior to development of overt cardiac dysfunction. In patients with transfusion dependent TM, compliance to an optimized chelation regimen can help improve regional myocardial function prior to progression to systolic dysfunction and clinically symptomatic sideroblastic complications.

An Unusual Case of Cardiac and Thyroid Metastasis From Lung Cancer

SESSION TITLE: Non-Small Cell Lung Cancer SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Lung cancer is the leading cause of cancer related death worldwide. It is metastatic in a significant percentage of patients at diagnosis. Common sites of metastasis include adrenals, brain, bone and liver. Uncommon sites include intestine, skin, heart and thyroid. We present a rare case of lung cancer with metastasis to heart and thyroid. CASE PRESENTATION: A 67 year old female presented with cough and hemoptysis for 3 weeks. Computerized tomography (CT) scan of the chest showed right sided lung mass with mediastinal lymphadenopathy. Positron emission tomography (PET-CT) scan showed increased uptake in these lesions, with no other activity outside the chest. Endobronchial ultrasound and biopsy confirmed the diagnosis of squamous cell lung cancer-stage IIIB (T2bN3M0), and she was started on chemotherapy. PET-CT done 2 months after treatment showed improvement in size of lung lesion and mediastinal lymph nodes, but new lesions were identified in the thoracic spine and ribs. Palliative radiotherapy was started in additional to chemotherapy. A PET-CT repeated after 3 months showed progression of disease with enlarging spine lesions and new lesion in the right lobe of thyroid. Thyroid lesion was biopsied and the histological findings were similar to the prior lung biopsy sample. Patient started having hemoptysis again and presented to emergency room. CT chest revealed multiple metastatic lesions in liver, large pericardial effusion and a mass involving the left ventricular lateral wall measuring up to 4.3 cm. Echocardiogram confirmed large pericardial effusion and a large extra-cardiac mass attached to the lateral wall of left ventricle. Given her prognosis and poor response to treatment, she opted for hospice care. DISCUSSION: More than one thirds of patients with lung cancer have spread at the time of diagnosis. Common sites of metastasis from lung cancer include adrenals, brain, bone and liver. Rarely lung cancer can metastasize to intestines, skin, heart and thyroid. Very few cases of cardiac metastasis from lung cancer are reported. Most cases are diagnosed on autopsy. About two thirds of all cardiac metastases involve the pericardium, one third the epicardium or myocardium and rarely the endocardium. Of all the cardiac metastasis, it is adenocarcinoma in 26%, squamous cell carcinoma in 23.4%, undifferentiated in 21.2%, and bronchoalveolar carcinoma in 17.4% of cases(1). Thyroid metastasis from primary lung cancer is an even rarer thing. Common cancers which metastasize to thyroid include colon and kidneys. On extensive literature review, we could find very few cases of lung metastases to thyroid. Our patient had unfortunately two unusual metastatic sites of lung cancer. CONCLUSIONS: Lung cancer can rarely metastasize to locations like heart and thyroid, and we report the only case in literature with combined cardiac and thyroid metastasis. Reference #1: Bussani R, De-Giorgio F, Abbate A, Silvestri F. Cardiac metastases. J Clin Pathol 2007;60:27-34. DISCLOSURE: The following authors have nothing to disclose: Jay Patel, Shejuti Guha, Vishesh Paul No Product/Research Disclosure Information

Post-infarction left ventricular pseudoaneurysm

Introduction Pseudoaneurysm of the left ventricle is a severe complication of myocardial infarction that results from a free cardiac wall rupture that is contained by the pericardium, thrombus, or adhesions. Most patients with a cardiac pseudoaneurysm will display symptoms of dyspnea or chest pain, but 10% of patients can be asymptomatic. Transthoracic Doppler color flow imaging is a suitable starting diagnostic method for diagnosing a pseudoaneurysm of the left ventricle. Cardiac magnetic resonance is an excellent complementary method for identifying this cardiac entity. Case description A patient in heart failure was admitted to receive intensive care therapy. An electrocardiogram showed anterolateral ST elevation and two-dimensional echocardiogram [2DE] posterolateral akinesis of the left ventricle. After a satisfactory in-hospital course he was discharged without any apparent complication. Six months later he was referred for new evaluation due to heart failure symptoms. A 2DE revealed a pseudoaneurysm along the left ventricular lateral wall. A cardiac magnetic resonance confirmed a pseudoaneurysm contained by the pericardium. Late gadolinium-enhanced imaging demonstrated a transmural lateral myocardial infarction with marked delayed enhancement of the pericardium that forms the wall of the pseudoaneurysm. Results and conclusions Early surgical intervention is recommended for a pseudoaneurysm of the left ventricle because of its tendency to rupture. Most patients do well after surgical repair, except for that requiring concomitant mitral valve replacement. However, the long-term outcomes of patients with a pseudoaneurysm not treated with surgery appear to be relatively benign, with a very low risk of fatal rupture. Therefore, a conservative approach may be considered in these patients that should include chronic anticoagulation therapy because of a high risk of ischemic stroke. Take-home message Transthoracic echocardiography is an acceptable starting diagnostic method in patients having a pseudoaneurysm. Cardiac magnetic resonance has been increasingly used as a non-invasive diagnostic method.

A dual therapy of off-pump temporary left ventricular extracorporeal device and amniotic stem cell for cardiogenic shock

BackgroundTemporary mechanical circulatory support device without sternotomy has been highly advocated for severe cardiogenic shock patient but little is known when coupled with amniotic stem cell therapy.Case presentationThis case reports the first dual therapy of temporary left ventricular extracorporeal device CentriMag with distal banding technique and human amniotic stem cell injection for treating a severe refractory cardiogenic shock of an 68-year-old female patient. A minimally-invasive off-pump LVAD was established by draining from the left ventricle and returning to the right axillary artery with distal arterial banding to prevent right upper extremity hyperperfusion. Amniotic stem cells were injected intramyocardially at the left ventricular apex, lateral wall, inferior wall, and right subclavian vein.ConclusionThe concomitant use of the temporary minimally-invasive off-pump CentriMag placement and stem cell therapy not only provided an alternative to cardiopulmonary bypass and full-median sternotomy procedures but may have also synergistically enhanced myocardial reperfusion and regeneration.

Echocardiographic Prediction of Cardiac Resynchronization Therapy Response Requires Analysis of Both Mechanical Dyssynchrony and Right Ventricular Function: A Combined Analysis of Patient Data and Computer Simulations

Pronounced echocardiographically measured mechanical dyssynchrony is a positive predictor of response to cardiac resynchronization therapy (CRT), whereas right ventricular (RV) dysfunction is a negative predictor. The aim of this study was to investigate how RV dysfunction influences the association between mechanical dyssynchrony and left ventricular (LV) volumetric remodeling following CRT. One hundred twenty-two CRT candidates (mean LV ejection fraction, 19±6%; mean QRS width, 168±21msec) were prospectively enrolled and underwent echocardiography before and 6months after CRT. Volumetric remodeling was defined as percentage reduction in LV end-systolic volume. RV dysfunction was defined as RV fractional area change<35%. Mechanical dyssynchrony was assessed as time to peak strain between the septum and LV lateral wall, interventricular mechanical delay, and septal systolic rebound stretch. Simulations of heart failure with an LV conduction delay in the CircAdapt computer model were used to investigate how LV and RV myocardial contractility influence LV dyssynchrony and acute CRT response. In the entire patient cohort, higher baseline septal systolic rebound stretch, time to peak strain between the septum and LV lateral wall, and interventricular mechanical delay were all associated with LV volumetric remodeling in univariate analysis (R=0.599, R=0.421, and R=0.410, respectively, P<.01 for all). The association between septal systolic rebound stretch and LV volumetric remodeling was even stronger in patients without RV dysfunction (R=0.648, P<.01). However, none of the mechanical dyssynchrony parameters were associated with LV remodeling in the RV dysfunction subgroup. The computer simulations showed that low RV contractility reduced CRT response but hardly affected mechanical dyssynchrony. In contrast, LV contractility changes had congruent effects on mechanical dyssynchrony and CRT response. Mechanical dyssynchrony parameters do not reflect the negative impact of reduced RV contractility on CRT response. Echocardiographic prediction of CRT response should therefore include parameters of mechanical dyssynchrony and RV function.

Left ventricular longitudinal function assessment in rabbits after acute occlusion of left anterior descending coronary artery by two-dimensional speckle tracking imaging

AbstactBackgroundTo evaluate the left ventricular (LV) longitudinal function changes in rabbits after acute occlusion of the left anterior descending artery (LAD) by two-dimensional speckle tracking imaging (2D–STI).MethodsForty-eight New Zealand white rabbits underwent echocardiography examination. EchoPAC was used to measure LV peak systolic longitudinal strain (LS) of the endocardium, middle myocardium, and epicardium, peak longitudinal strain rate (LSr), segmental and global longitudinal rotation (LR) degrees. Ligated the LAD and repeated all measurements after 10 min.ResultsPeak LS and LSr were significantly different between the preoperative and postoperative rabbits among most LV walls (P < 0.05). In apical four-chamber view, there was significant difference in the degrees of rotation of the LV lateral wall in preoperative and postoperative rabbits (P < 0.05). In apical three-chamber view, the rotation degrees of the posterior wall and the LR were significantly lower in the postoperative than in the preoperative (P < 0.001). In apical two-chamber view, the rotation degrees of the inferior wall and the LR were significantly lower in the postoperative (P < 0.05).ConclusionsLeft ventricular function was impaired after acute occlusion of LAD. Segmental rotational degrees and changes in LR could be useful indicators of cardiac function during the early phases of acute myocardial ischemia.

Deleterious acute and chronic effects of bradycardic right ventricular apex pacing: consequences for arrhythmic outcome.

In the chronic complete atrioventricular (AV) block dog (CAVB) model, both bradycardia and altered ventricular activation due to the uncontrolled idioventricular rhythm contribute to ventricular remodeling and the enhanced susceptibility to Torsade de Pointes (TdP) arrhythmias. We investigated the effect of permanent bradycardic right ventricular apex (RVA) pacing on mechanical and electrical remodeling and TdP. In 23 anesthetized dogs, serial experiments were performed at sinus rhythm (SR), acutely after AV block (AAVB) and 3weeks of remodeling CAVB at a fixed pacing rate of 60/min. ECG, and left (LV) and right ventricular (RV) monophasic action potentials durations (MAPD) were recorded; activation time (AT) and activation recovery interval (ARI) were determined from ten distinct LV electrograms; interventricular mechanical delay (IVMD) and time-to-peak strain (TTP) of the LV septal and lateral wall (ΔTTP: lateral wall minus septal wall) were obtained echocardiographically. Dofetilide (25μg/kg/5min) was infused to study TdP inducibility. In baseline AAVB, in comparison to SR, RVA bradypacing acutely increased QT interval, LV, and RVMAPD. Echocardiographic IVMD and ΔTTP were initially increased, which was partially corrected after 3weeks of RVA pacing (IVMD: 22±13 vs. 42±11 vs. 31±6ms; ΔTTP: -2±47 vs. -114±38 vs. -36±22ms). QT interval (362±23 vs. 373±29ms), LVMAPD (245±18 vs. 253±22ms), RVMAPD (226±26 vs. 238±31ms), and mean LV-ARI (268±5 vs. 267±6ms) were not significantly changed after 3weeks of RVA pacing. During AAVB, dofetilide increased mean LV-ARI (381±11ms) with largest increases in the later activated basal areas (slope AT-ARI: +0.96). In contrast with acute RVA pacing, 3week pacing increased TdP inducibility (0/13 vs. 11/21) and mean LV-ARI (484±18ms), while the slope of AT-ARI responded differently on dofetilide (-2.37), with larger APD increases in the early region. The latter was supported at the molecular level: reduced RNA expressions of three repolarization-related ion channel genes in early (KCNQ1, KCNH2, and KCNJ2) versus two in late regions (KNCQ1 and KCNJ2). In conclusion, bradycardic RVA pacing acutely induced LV intra- and interventricular mechanical dyssynchrony, which was partially reversed after 3weeks of pacing (remodeling). The latter occurred without apparent baseline electrical effects. However, dofetilide clearly unmasked (region-specific) arrhythmic consequences of remodeling.

Association of native T1 times with biventricular function and hemodynamics in precapillary pulmonary hypertension.

In precapillary pulmonary hypertension (PH) patients, we sought to (1) investigate the relationship between ventricular insertion point (VIP) T1 times, hemodynamic parameters, and biventricular function, and (2) determine the predictors of anterior and inferior VIP T1 time. Twenty-two patients with precapillary PH underwent 1.5-T cardiac MR, right heart catheterization (RHC), and echocardiography. A group of 10 healthy age- and sex-matched volunteers served as controls. Biventricular function, morphology and mass were obtained from short-axis cine images. Native T1 times at anterior, inferior VIP, septum and LV lateral wall were respectively derived from all subjects. Mixed venous oxygen saturation (SvO2) was the strongest hemodynamic parameters correlating with anterior (rp=-0.67, P = 0.001) and inferior VIP T1 time (rp=-0.81, P < 0.001). Elevated VIP T1 times were associated with reduced right ventricular (RV) ejection fraction, RV longitudinal and transverse motion, and increased RV end-diastolic and end-systolic volume index. LV diastolic function, quantified as mitral E velocity, was negatively correlated with anterior, inferior VIP (rp=-0.55, P = 0.01) and septal T1 times (rp=-0.50, P = 0.02), and positively correlated with RV systolic function and wall motion. In multivariate linear regression analyses, systolic eccentricity index (sEI) was the independent predictor of average VIPs T1 time (β= 0.47, P < 0.01), and remained significant correlation after adjustment of RHC and demographic parameters. In patients with precapillary PH, VIP T1 times are associated with biventricular function and hemodynamic parameters. Among all the parameters, sEI acts as a determinant of average VIPs T1 time.