Basic echocardiographic features of patients with latent left ventricular outflow tract obstruction without left ventricular hypertrophy

Left ventricular outflow tract obstruction (LVOTO) is commonly observed in patients with hypertrophic cardiomyopathy (HCM) or left ventricular hypertrophy (LVH). While some patients develop LVOTO at rest, it can also be provoked by physical exertion, and hence termed latent LVOTO (L-LVOTO). Recent reports demonstrated that L-LVOTO develops not only in LVH patients, but also in patients without LVH (non-LVH). However, the prevalence and clinical prognosis of non-LVH patients with L-LVOTO are not yet elucidated. In this study, we retrospectively investigated the echocardiographic features of patients with malignancy who underwent dobutamine stress echocardiography (DSE) to evaluate preoperative cardiac risk. One hundred ninety-nine patients were found not to have LVH or coronary artery disease. Among them, 106 patients exhibited L-LVOTO after DSE. We next compared the baseline echocardiographic features of L-LVOTO (+) patients with those of L-LVOTO (-) patients, and identified the left ventricular outflow tract (LVOT) ratio (systolic LVOT diameter/diastolic LVOT diameter) as a significant predictor of L-LVOTO. An LVOT ratio ≤ 0.83 was the best cutoff value to detect the presence of L-LVOTO, with a sensitivity of 81.1% and specificity of 80.6%. Overall, L-LVOTO was found to develop in almost half of non-LVH patients with malignancy. In addition, the baseline LVOT ratio was strongly related to the presence of L-LVOTO in non-LVH patients. Therefore, patients with dynamic LVOT narrowing may benefit from DSE to detect the presence of L-LVOTO.     

运动负荷超声在评估肥厚型心肌病梗阻类型中的应用

目的 评估肥厚型心肌病(HCM)患者静息和运动中左室流出道梗阻的情况.方法 连续入选的60例静息左室流出道压差(LVOTG) ＜50 mm Hg(1 mm Hg=0.133 kPa)的HCM患者,超声测量静息LVOTG和运动峰值LVOTG.51例静息LVOTG＜ 30 mm Hg的患者中,26例患者运动峰值LVOTG≥30 mm Hg为潜在梗阻,25例运动峰值LVOTG＜ 30 mm Hg为非梗阻.9例静息LVOTG30 ～49 mm Hg为静息梗阻.分析不同类型梗阻的形态学特征.结果 潜在梗阻与非梗阻患者相比,二尖瓣前叶收缩期前向运动(SAM)征(73.1％比8.0％)、流出道狭窄(46.2％比4.0％)更常见、二尖瓣反流程度更重、静息LVOTG[(16.9±7.2) mm Hg比(7.1 ±4.3)mm Hg]更高,室间隔肥厚部位分布差异有统计学意义(P值均＜0.05).多因素logistic回归分析,SAM征(OR 6.431,95％ CI2.323 ～291.112,P=0.002)和室间隔肥厚部位(OR0.011,95％ CI0.001 ～0.179,P=0.008)为发生潜在梗阻的独立预测因素.结论 约半数静息无梗阻的HCM患者存在潜在梗阻.SAM征和室间隔肥厚部位有助于潜在梗阻的识别.     

Left atrial function by two-dimensional speckle tracking echocardiography in patients with severe rheumatic mitral stenosis and pulmonary hypertension

We studied left atrial (LA) function in severe rheumatic mitral stenosis (MS) patients using two-dimensional speckle tracking echocardiography (STE). Eighty patients with isolated severe MS in sinus rhythm and 40 controls underwent comprehensive echocardiography including STE derived LA strain [reservoir strain (LAS_r), conduit strain (LAS_cd) and contractile strain (LAS_ct)]. The mean MVA was 0.93 ± 0.21 cm². The mean values of LAS_r (14.73 ± 8.59%), LAS_cd (?7.61 ± 4.47%) and LAS_ct (?7.16 ± 5.15%) in patients were significantly lower (p < 0.001) vs. controls 44.11 ± 10.44%, ?32.45 ± 7.63%, ?11.85 ± 6.77% respectively and showed decreasing trend with increasing MS severity and higher NYHA class. In conclusion, LA dysfunction is prevalent in severe MS irrespective of NYHA functional class.     

Speckle tracking echocardiography in patients with systemic lupus erythematosus: A meta-analysis

BackgroundSystemic lupus erythematosus (SLE), is characterized by a systemic involvement including myocardial dysfunction. Being standard echocardiography not able at fully detecting subclinical alterations, speckle tracking echocardiography (STE) has recently emerged as a quantitative ultrasound technique to accurately estimate myocardial function.MethodsWe conducted a systematic review with meta-analysis of studies reporting STE parameters in patients with SLE.ResultsA total of 9 studies were included in the analysis. Left ventricle global longitudinal strain (GLS) was significantly lower in SLE patients than in non-SLE controls (MD: −2.331, 95% CI: −3.083, −1.580, p < 0.001). In addition, we found significant differences between SLE patients and non-SLE controls in left ventricle GLS rate (MD: −0.115, 95% CI: −0.177 to 0.063, p < 0.001), left ventricle circumferential strain(MD: −1.841, 95% CI: −3.160 to 0.521, p = 0.006) and left ventricle radial strain(MD: −11.03, 95% CI: −13.819 to 8.241, p < 0.001). Right ventricle strain was significantly lower in SLE patients than in non-SLE controls (MD: −5.814, 95% CI: −7.347, −4.281, p < 0.001). Meta-regression models showed a lower difference in left ventricle GLS between SLE cases and controls for studies with a higher prevalence of female gender and higher prevalence of hypertension.ConclusionsSLE patients have lower STE parameters than controls, thus suggesting the presence of an impaired myocardial function involving both left and right ventricle.     

Isolated hypertrophy of the basal ventricular septum: Characteristics of patients with and without outflow tract obstruction

Background

Isolated basal septal hypertrophy (IBSH) of the left ventricle (LV) is not a well understood phenomenon, particularly in the presence of concomitant left ventricular outflow tract obstruction (LVOTO). We evaluated the prevalence of IBSH and compared those with and without LVOTO.

Methods

Retrospective observational study of 4104 consecutive patients undergoing echocardiography at a community cardiology practice and a hospital without specialized Hypertrophic Cardiomyopathy (HCM) service to determine prevalence of IBSH, defined as isolated hypertrophy (> 15 mm) of the basal LV septum (BS) without hypertrophy elsewhere. Clinical, ECG and echocardiographic characteristics were compared in IBSH with and without LVOTO.

Results

Prevalence of IBSH was 5.8% (240/4104): mean (SD) age was 76.0y (10.4) with equal gender distribution. Prevalence increased with age (p < 0.001 for trend), reaching 7.8% over 70y. None had a family history of HCM, and HCM-associated ECG changes were uncommon. Mean BS thickness (SD) was 17.8 mm (0.24) with a BS/posterior wall ratio (SD) of 1.76 (0.31). Resting peak LVOT gradient (> 20 mm Hg) was present in 8/240 (3.3%), mean (SD) 69.6mm Hg (59.3). Patients with LVOTO had hypercontractile LV function (fractional shortening [SD] 51.8% [9.5] vs. 40.5% [10.9], p = 0.012) compared to those without LVOTO, but had similar BS thickness [SD] (17.8 mm [3.0] vs. 17.8 mm [2.8], p = 0.996) and ECG characteristics. Greater apical and septal displacements of the mitral valve co-aptation point characterized those with IBSH and LVOTO.

Conclusions

IBSH is common in elderly patients referred for echocardiography. LVOTO occurs only when concomitant mitral valve co-aptation and LV hypercontractility facilitate development of a gradient, rather than through differences in the degree of BS myocardial hypertrophy.     

Subclinical left ventricular dysfunction during systemic lupus erythematosus activity with follow-up after remission – A speckle tracking echocardiographic study

Aim of the workTo investigate the subclinical left ventricular (LV) dysfunction in patients with active systemic lupus erythematosus (SLE) using speckle tracking echocardiography (STE). The echocardiographic parameters were followed up when the disease activity was controlled.Patients and methodsThis prospective study included 63 patients with active SLE and LV ejection fraction (EF) ≥50%.Safety of Estrogens in Lupus Erythematosus: National Assessment – Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) was assessed and categorized as mild/moderate (≤12) or severe (>12). Fifty SLE patients continued follow-up after 3–6 months of the disease remission. Fifty age- and gender-matched healthy individuals acted as the control group. The measured STE parameters included LV deformation (global longitudinal strain [GLS] and global circumferential strain [GCS]) and rotational parameters (rotation, twist, and torsion).ResultsThe patients were 56 females and 7 males (F:M 8:1) and median age 26 years (IQR: 21–31 years) and a disease duration of 3 years (IQR 2–5 years. Active SLE patients showed worse strain parameters than controls (mean GLS ?19.9%±2.1 vs ?22.7%±1.3 and mean GCS ?21.2 ± 2.5% vs ?25.1 ± 1.7% respectively; p < 0.001 for both). Patients had lower LV rotational parameters (p < 0.001 for all). STE parameters were similar in patients with mild-moderate and severe activity and improved after remission in both groups.ConclusionActive SLE patients had modest LV dysfunction by STE despite having normal function by traditional echocardiography. Disease remission resulted in the improvement of STE parameters. STE is a simple tool to use in SLE activity scores to detect early cardiac dysfunction.     

Use of Doppler echocardiography and amyl nitrite inhalation to characterize left ventricular outflow obstruction in hypertrophic cardiomyopathy

The presence of left ventricular outflow tract obstruction (LVOTO) of either a resting or dynamic nature may have important therapeutic and prognostic implications in patients with hypertrophic cardiomyopathy (HCM). Doppler echocardiograms combined with amyl nitrite (Amyl) inhalation were performed in 333 consecutive patients referred for suspected HCM to diagnose and categorize the nature and severity of LVOTO. Hypertrophic cardiomyopathy was present by 2-D and M-mode criteria in 145/333 (44 percent) patients. Normal limits of resting and post-Amyl continuous wave Doppler peak left ventricular outflow tract velocities were established in 15 subjects with completely normal 2-D and Doppler echocardiograms. Based on these criteria, of the 145 patients with HCM, 63 (43 percent) were classified as having resting LVOTO, peak velocity 4.2 +/- 1.3 m/s. Among 82 patients with HCM without resting LVOTO, 47 (57 percent) received Amyl. Latent LVOTO was provoked in 25/47 (53 percent), peak post-Amyl velocity 4.5 +/- 1.2 m/s. The remaining 22 (47 percent) had nonobstructive HCM, as indicated by no significant increase in post-Amyl velocity. Among a total 62 subjects receiving Amyl, none experienced serious morbidity or mortality. Doppler echocardiography, in conjunction with Amyl inhalation in selected patients, is a useful noninvasive method to diagnose and categorize patients with HCM according to the nature and severity of LVOTO.     

Mecânica Atrial na Cardiomiopatia Hipertrófica: Discriminando Hipertrofia de Fibrose Ventricular

BackgroundHypertrophic cardiomyopathy (HCM) and left ventricular hypertrophy (LVH) secondary to systemic hypertension (HTN) may be associated with left atrial (LA) functional abnormalities.ObjectivesWe aimed to characterize LA mechanics in HCM and HTN and determine any correlation with the extent of left ventricular (LV) fibrosis measured by cardiac magnetic resonance (CMR) in HCM patients.MethodsTwo-dimensional speckle tracking-derived longitudinal LA function was acquired from apical views in 60 HCM patients, 60 HTN patients, and 34 age-matched controls. HCM patients also underwent CMR, with measurement of late gadolinium enhancement (LGE) extension. Association with LA strain parameters was analyzed. Statistical significance was set at p<0.05.ResultsMean LV ejection fraction was not different between the groups. The E/e’ ratio was impaired in the HCM group and preserved in the control group. LA mechanics was significantly reduced in HCM, compared to the HTN group. LA strain rate in reservoir (LASRr) and in contractile (LASRct) phases were the best discriminators of HCM, with an area under the curve (AUC) of 0.8, followed by LA strain in reservoir phase (LASr) (AUC 0.76). LASRr and LASR-ct had high specificity (89% and 91%, respectively) and LASr had sensitivity of 80%. A decrease in 2.79% of LA strain rate in conduit phase (LASRcd) predicted an increase of 1cm in LGE extension (r²=0.42, β 2.79, p=0.027).ConclusionsLASRr and LASRct were the best discriminators for LVH secondary to HCM. LASRcd predicted the degree of LV fibrosis assessed by CMR. These findings suggest that LA mechanics is a potential predictor of disease severity in HCM.     

Prognostic Utility of Echocardiographic Atrial and Ventricular Strain Imaging in Patients With Cardiac Amyloidosis

ObjectivesThe prognostic value of echocardiographic atrial and ventricular strain imaging in patients with biopsy-proven cardiac amyloidosis was assessed.BackgroundAlthough left ventricular global longitudinal strain (GLS) is known to be predictive of outcome, the additive prognostic value of left (LA), right atrial (RA), and right ventricular (RV) strain is unclear.MethodsOne hundred thirty-six patients with cardiac amyloidosis and available follow-up data were studied by endomyocardial biopsy, noncardiac biopsy with supportive cardiac imaging, or autopsy confirmation. One hundred nine patients (80%) had light-chain, 23 (17%) had transthyretin, and 4 (3%) had amyloid A type cardiac amyloidosis. GLS, RV free wall strain, peak longitudinal LA strain, and peak longitudinal RA strain were measured from apical views. Clinical and routine echocardiographic data were compared. All-cause mortality was followed (median 5 years).ResultsStrain data were feasible for GLS in 127 (93%), LA strain in 119 (88%), RA strain in 117 (86%), and RV strain in 102 (75%). Strain values from all 4 chambers were significantly associated with survival. Hazard ratio (HR) and 95% confidence interval (CI) for low median strain values were as follows: GLS, HR: 2.3; 95% CI: 1.3 to 3.8 (p < 0.01); LA strain, HR: 7.5; 95% CI: 3.8 to 14.7 (p < 0.001); RA strain, HR: 3.5; 95% CI: 2.0 to 6.2 (p < 0.001); and RV free wall strain, HR: 2.8; 95% CI: 1.5 to 5.1 (p < 0.001). Peak longitudinal LA strain and RV strain remained independently associated with survival in multivariable analysis. Peak LA strain had the strongest association with survival (p < 0.001), and LA strain combined with GLS and RV free wall strain had the highest prognostic value (p < 0.001).ConclusionsStrain data from all 4 chambers had important prognostic associations with survival in patients with biopsy-confirmed cardiac amyloidosis. Peak longitudinal LA strain was particularly associated with prognosis. Atrial and ventricular strain have promise for clinical utility.     

Relation of atrial electromechanical delay to P-wave dispersion on surface ECG using vector velocity imaging in patients with hypertrophic cardiomyopathy

Objectives

Heterogeneity of structural and electrophysiologic properties of atrial myocardium is common characteristic in hypertrophic cardiomyopathy (HCM). We assessed the dispersion of atrial refractoriness on surface ECG using P-wave dispersion (PWD) and its relation to atrial electromechanical functions using vector velocity imaging (VVI) in HCM population.

Methods

Seventy-nine HCM patients (mean age: 43.7 ± 13 years, 67% male) were compared with 25 healthy individuals as control. P-wave durations, P_max and P_min, P-wave dispersion (PWD), and P terminal force (PTF) were measured from 12-lead ECG. LA segmental delay (TTP-d) and dispersion (TTP-SD) of electromechanical activation were derived from atrial strain rate curves.

Results

HCM patients had longer PR interval, PW duration, higher PWD, PTF, QT_c compared to control (p < .001). HCM patients were classified according to presence of PWD into two groups, group I with PWD > 46 ms (n = 25) and group II PWD ≤ 46 ms (n = 54). Group I showed higher prevalence of female gender, higher PTF, QTc interval, left ventricular outflow tract (LVOT) obstruction, p < .01, LVOT gradient (p < .001), LV mass index (p < .01), E/E' (p < .01), and severe mitral regurgitation (p < .001). Moreover, PWD was associated with increased atrial electromechanical delay (TTP-d) and LA mechanical dyssynchrony (TTP-SD), p < .001. LA segmental delay and dispersion of electromechanical activation were distinctly higher among HCM patient.

Conclusion

PWD is simple ECG criterion, and it is associated with more severe HCM phenotype and LA electromechanical delay while PTF is linked only to atrial remodeling.

     

Independent effect of visceral fat on left atrial phasic function in the general population

Background and aimsObesity increases the risk for atrial fibrillation (AF), although the impact of abdominal fat distribution on left atrial (LA) morphology and functional remodeling remains unclear. This study aimed to investigate whether increased abdominal adiposity is independently associated with impaired LA function and/or LA enlargement in a sample of the general population and to evaluate the role of adipokines in this association.Methods and resultsThe study cohort consisted of 527 participants (362 men; 57 ± 10 years) without overt cardiac disease who underwent laboratory testing, abdominal computed tomographic examination and echocardiography. Abdominal adiposity was quantitatively assessed as visceral fat area (VFA) and subcutaneous fat area (SFA) at the level of the umbilicus. Speckle-tracking echocardiography was performed to assess LA phasic function including reservoir, conduit and pump strain. LA reservoir and conduit strain decreased with increasing VFA quartiles (both p < 0.05), whereas no significant differences were observed in LA volume index and pump strain. When stratified by SFA, there were no significant differences in LA size and function across the quartiles. In multivariable analysis, VFA was significantly associated with LA conduit strain independent of cardiovascular risk factors, and pertinent laboratory and echocardiographic parameters (standardized β = −0.136, p = 0.019). VFA was correlated with serum adiponectin level (r = −0.51, p < 0.001), but there was no association between adiponectin level and three LA phasic strains.ConclusionIn a sample of the general population, VFA accumulation was independently associated with worse LA conduit strain, which may be involved in the pathophysiological mechanism of obesity-related AF.     

Impact of Left Ventricular Outflow Tract Calcification on Procedural Outcomes After Transcatheter Aortic Valve Replacement

ObjectivesThis study aimed to systematically assess the importance of left ventricular outflow tract (LVOT) calcification on procedural outcomes and device performances with contemporary transcatheter heart valve (THV) systems.BackgroundLVOT calcification has been associated with adverse clinical outcomes after transcatheter aortic valve replacement (TAVR). However, the available evidence is limited to observational data with modest numbers and incomplete assessment of the effect of the different THV systems.MethodsIn a retrospective analysis of a prospective single-center registry, LVOT calcification was assessed in a semiquantitative fashion. Moderate or severe LVOT calcification was documented in the presence of 2 nodules of calcification, or 1 extending >5 mm in any direction, or covering >10 % of the perimeter of the LVOT.ResultsAmong 1,635 patients undergoing TAVR between 2007 and 2018, moderate or severe LVOT calcification was found in 407 (24.9%). Patients with moderate or severe LVOT calcification had significantly higher incidences of annular rupture (2.3% vs. 0.2%; p < 0.001), bailout valve-in-valve implantation (2.9% vs. 0.8%; p = 0.004), and residual aortic regurgitation (11.1% vs. 6.3%; p = 0.002). Balloon-expandable valves conferred a higher risk of annular rupture in the presence of moderate or severe LVOT calcification (4.0% vs. 0.4%; p = 0.002) as compared with the other valve designs. There was no significant interaction of valve design or generation and LVOT calcification with regard to the occurrence of bailout valve-in-valve implantation and residual aortic regurgitation.ConclusionsModerate or severe LVOT calcification confers increased risks of annular rupture, residual aortic regurgitation, and implantation of a second valve. The risk of residual aortic regurgitation is consistent across valve designs and generations. (SWISS TAVI Registry; NCT01368250)     

Strain patterns in primary mitral regurgitation due to rheumatic heart disease and mitral valve prolapse

ObjectiveLeft atrial (LA) and left ventricular (LV) remodelling are the adaptive changes that occur in primary mitral regurgitation (MR) and are related to its clinical outcomes. Despite the pathophysiological differences in MR in rheumatic heart disease (RHD) and mitral valve prolapse (MVP), whether the pattern of LV and LA remodelling is different between the two conditions remains unknown. Hence, we compared the LA and LV strain pattern in MR due to RHD, the predominant etiology in developing countries topatients with MVP and age and sex-matched controls.MethodsA total of 50 patients of severe MR which included 30 MVP MR and 20 RHD MR were assessed by strain imaging by speckle tracking echocardiography (STE) and were compared with age and sex-matched controls. 2D STE was used for LA and 3D STE was used for LV strain analysis. LA and LV strain parameters were compared between MVP MR and RHD MR groups.Results30 patients with MVP and 20 with RHD were studied. 60% (n = 30) were symptomatic. Mean GLS was ?17.2 ± 4.4% compared to ?20 ± 3.2% among controls and mean LA strain was 17.35 ± 10.3% compared to 51.34 ± 11.5% among controls which were significantly lower (both p < 0.01). No significant difference in LA strain and GLS was found between MVP and RHD subgroups (LA strain 20.45 ± 11.9% and 14.63 ± 8.85%; p = 0.08; GLS - 18.25 ± 4.3% and-16.2 ± 4.6%; p = 0.12). PALS in the RHD group was lower compared to MVP(p = 0.08) which showed a trend towards significance. LV strain parameters showed no significant difference among the MVP and RHD groups.ConclusionLA and LV strain parameters showed no significant difference in MR due to either RHD or MVP. There was a trend towards lower LA strain in RHD which needs validation with large multicentric studies. The current strain parameters from MVP with the prognostic value may be applied to MR of RHD etiology, pending confirmation of our results by other groups.     

Dobutamine Stress Echocardiography Identifies Patients with Angina and Dynamic Left Ventricular Outflow Obstruction in Physiological Exercise

Background and Methods: To determine whether patients with no heart disease who develop dynamic left ventricular outflow obstruction (DLVOTO) during dobutamine echocardiography (DE) reproduce the phenomenon during exercise echocardiography (EE), DE and EE were performed in 78 patients (59 ± 9 years) with effort angina and no alterations in SPECT. Thirty-eight (48.7%) patients had DLVOTO during DE and 15 (19.2%) during EE. This phenomenon during EE was reproducible in 39.4% of the patients with DLVOTO on DE, and 100% of the patients with DLVOTO during EE had it during DE. Independent factors predicting DLVOTO during EE were the LVOT diameter (OR 0.33 (0.14–0.74)) and the left ventricular (LV) mass index (OR 1.05 (1.01–1.08)). No cardiovascular events were noted after 26 ± 3 months. The reproducibility of DLVOTO during EE in patients with unexplained angina and with DLVOTO on DE is associated with the size of the LVOT and the LV mass index. The long-term prognosis is excellent.     

3-Dimensional Versus 2-Dimensional STE for Right Ventricular Myocardial Fibrosis in Patients With End-Stage Heart Failure

BackgroundLongitudinal strain of the right ventricular (RV) free wall (RVFWLS) assessed by 2-dimensional (2D) speckle-tracking echocardiography (STE) has been recently demonstrated to correlate with the extent of RV myocardial fibrosis (MF). However, the value of 3-dimensional (3D) STE–derived strain parameters in predicting RV MF has not been investigated in patients with end-stage heart failure (HF).ObjectivesThis study aimed to determine which RV strain parameter assessed by 2D-STE and 3D-STE was the most reliable parameter for predicting RV MF in patients with end-stage HF against histological confirmation of MF.MethodsA total of 105 consecutive patients with end-stage HF undergoing heart transplantation were enrolled in our study. The conventional RV function parameters, 2D-RVFWLS, and 3D-RVFWLS were obtained in these patients. The degree of MF was quantified by Masson trichrome staining in RV myocardial samples. The study population was divided into 3 groups according to the degree of MF on histology.ResultsPatients with severe MF had lower 3D-RVFWLS, 2D-RVFWLS, and conventional parameters of RV function compared with those with mild and moderate MF. RV MF strongly correlated with 3D-RVFWLS (r = ?0.72; p < 0.001), modestly with 2D-RVFWLS (r = ?0.53; p < 0.001), and weakly with conventional RV function parameters (r = ?0.21 to ?0.49; p < 0.01). 3D-RVFWLS correlated best with the degree of MF (r = ?0.72 vs. ?0.21 to ?0.53; p < 0.05) compared with 2D-RVFWLS and conventional RV function parameters. 3D-RVFWLS had the highest accuracy for detecting severe MF (area under the receiver-operating characteristic curve: 0.90 vs. 0.24–0.80; p < 0.05) compared with 2D-RVFWLS and conventional RV parameters. The model with 3D-RVFWLS (R² = 0.63; p < 0.001) was better in predicting the degree of RV MF than that with 2D-RVFWLS (R² = 0.54; p < 0.001).Conclusions3D-RVFWLS may be the most robust echocardiographic measure for predicting the extent of RV MF in patients with end-stage HF.     

肥厚性心肌病心衰患者左室流出道压差和运动心肺功能研究

目的：通过多巴酚丁胺负荷超声心动图和心肺运动联合试验（CPET）评价左室射血分数正常的心肌肥厚病临床心衰患者左室流出道（LVOT）压差,心房大小和运动心肺功能变化。方法：对35例正常人,62例梗阻型肥厚性心肌病（HCM）心衰患者进行多巴酚丁胺负荷脉冲型,连续波型,彩色多普勒超声心动图和CPET。测定LVOT压差,左房内径,于运动前、运动高峰和运动后分别测定峰氧耗量,无氧代谢阈（AT）,每分通气量/二氧化碳排出量（.VE/.VCO2）斜率。结果：与正常人相比较,LVOT梗阻的HCM心衰组患者左室短轴缩短率[（31±9）%∶（37±11）%]明显增大、LVOT压差[静态（3.9±1.1）mmHg∶（64±36）mmHg,负荷（13±7）mmHg∶（132±34）mmHg]明显增加、左房内径[（3.0±0.6）cm∶（4.3±0.7）cm]明显增大、A峰[（55±18）cm/s∶（81±35）cm/s]明显增高,峰值耗氧量[（32±7.9）ml/kg/min∶（18.4±5.8）ml/kg/min]、无氧阈（.VO2AT）[（16.5±2.1）ml/kg/min∶（9.2±2.2）ml/kg/min]明显下降,.VE/.VCO2斜率[（25.7±4.0）∶（32.8±5.1）]显著增加,P〈0.05~0.01。结论：左室流出道梗阻型肥厚性心肌病心衰患者,心房和心肺运动功能有明显改变。负荷超声和心肺运动联合试验有助于评价梗阻型肥厚性心肌病心衰患者左室流出道压差和运动时心肺功能。     

Assessing the true severity of low-gradient aortic stenosis using resting echocardiography

BackgroundDobutamine stress echocardiography (DSE) is required to determine whether low-gradient aortic stenosis (AS) with a small aortic valve area (AVA) is truly severe. The purpose of the present study was to evaluate the usefulness of ejection dynamics parameters at resting echocardiography for predicting the result of DSE performed in patients with low-gradient AS.MethodsThe results of resting echocardiography and DSE performed on 51 AS patients with low mean-gradient (<40 mmHg) and small indexed AVA (<0.60 cm²/m²) were retrospectively reviewed. Acceleration time (AT) and the ratio of AT to ejection time (ET) were measured on the recorded images. True-severe AS was defined as that with indexed projected AVA < 0.60 cm²/m².ResultsTwenty-six (51%) patients had true-severe AS, while 22 (43%) patients had preserved left ventricular ejection fraction (≥50%). Baseline indexed AVA and AT/ET were independently associated with indexed projected AVA at DSE. AT/ET was the only independent determinant of valve compliance. Indexed AVA ≤ 0.493 cm²/m² and AT/ET > 0.334 at baseline had sensitivities of 69% and 65% and specificities of 84% and 84%, respectively, for predicting true-severe AS. The presence of either indexed AVA ≤ 0.493 cm²/m² or AT/ET > 0.334 had a higher sensitivity (88%), and their co-occurrence had a higher specificity (100%).ConclusionsIndexed projected AVA at DSE was predicted by AT/ET, which represented valve compliance, along with indexed AVA. The true severity of low-gradient AS can be screened using a combination of resting indexed AVA and AT/ET without performing DSE.     

Progression of Myocardial Fibrosis in Hypertrophic Cardiomyopathy: A Cardiac Magnetic Resonance Study

ObjectivesThis study examined fibrosis progression in hypertrophic cardiomyopathy (HCM) patients, as well as its relationship to patient characteristics, clinical outcomes, and its effect on clinical decision making.BackgroundMyocardial fibrosis, as quantified by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR), provides valuable prognostic information in patients with HCM.MethodsA total of 157 patients with HCM were enrolled in this study, with 2 sequential CMR scans separated by an interval of 4.7 ± 1.9 years.ResultsAt the first CMR session (CMR-1), 70% of patients had LGE compared with 85% at CMR-2 (p = 0.001). The extent of LGE extent increased between the 2 CMR procedures, from 4.0 ± 5.6% to 6.3 ± 7.4% (p < 0.0001), with an average LGE progression rate of 0.5 ± 1.0%/year. LGE mass progression was correlated with higher LGE mass and extent on CMR-1 (p = 0.0017 and p = 0.007, respectively), greater indexed left ventricular (LV) mass (p < 0.0001), greater LV maximal wall thickness (p < 0.0001), apical aneurysm at CMR-1 (p < 0.0001), and lower LV ejection fraction (EF) (p = 0.029). Patients who were more likely to have a higher rate of LGE progression presented with more severe disease at baseline, characterized by LGE extent >8% of LV mass, indexed LV mass >100 g/m², maximal wall thickness ≥20 mm, LVEF ≤60%, and apical aneurysm. There was a significant correlation between the magnitude of LGE progression and future implantation of insertable cardioverter-defibrillators (p = 0.004), EF deterioration to ≤50% (p < 0.0001), and admission for heart failure (p = 0.0006).ConclusionsMyocardial fibrosis in patients with HCM is a slowly progressive process. Progression of LGE is significantly correlated with a number of clinical outcomes such as progression to EF ≤50% and heart failure admission. Judicious use of serial CMR with LGE can provide valuable information to help patient management.     

Identification of Myocardial Disarray in Patients With Hypertrophic Cardiomyopathy and Ventricular Arrhythmias

BackgroundMyocardial disarray is a likely focus for fatal arrhythmia in hypertrophic cardiomyopathy (HCM). This microstructural abnormality can be inferred by mapping the preferential diffusion of water along cardiac muscle fibers using diffusion tensor cardiac magnetic resonance (DT-CMR) imaging. Fractional anisotropy (FA) quantifies directionality of diffusion in 3 dimensions. The authors hypothesized that FA would be reduced in HCM due to disarray and fibrosis that may represent the anatomic substrate for ventricular arrhythmia.ObjectivesThis study sought to assess FA as a noninvasive in vivo biomarker of HCM myoarchitecture and its association with ventricular arrhythmia.MethodsA total of 50 HCM patients (47 ± 15 years of age, 77% male) and 30 healthy control subjects (46 ± 16 years of age, 70% male) underwent DT-CMR in diastole, cine, late gadolinium enhancement (LGE), and extracellular volume (ECV) imaging at 3-T.ResultsDiastolic FA was reduced in HCM compared with control subjects (0.49 ± 0.05 vs. 0.52 ± 0.03; p = 0.0005). Control subjects had a mid-wall ring of high FA. In HCM, this ring was disrupted by reduced FA, consistent with published histology demonstrating that disarray and fibrosis invade circumferentially aligned mid-wall myocytes. LGE and ECV were significant predictors of FA, in line with fibrosis contributing to low FA. Yet FA adjusted for LGE and ECV remained reduced in HCM (p = 0.028). FA in the hypertrophied segment was reduced in HCM patients with ventricular arrhythmia compared to patients without (n = 15; 0.41 ± 0.03 vs. 0.46 ± 0.06; p = 0.007). A decrease in FA of 0.05 increased odds of ventricular arrhythmia by 2.5 (95% confidence interval: 1.2 to 5.3; p = 0.015) in HCM and remained significant even after correcting for LGE, ECV, and wall thickness (p = 0.036).ConclusionsDT-CMR assessment of left ventricular myoarchitecture matched patterns reported previously on histology. Low diastolic FA in HCM was associated with ventricular arrhythmia and is likely to represent disarray after accounting for fibrosis. The authors propose that diastolic FA could be the first in vivo marker of disarray in HCM and a potential independent risk factor.     

Myocardial Histopathology in Patients With Obstructive Hypertrophic Cardiomyopathy

BackgroundHypertrophic cardiomyopathy (HCM) is characterized by multiple pathological features including myocyte hypertrophy, myocyte disarray, and interstitial fibrosis.ObjectivesThis study sought to correlate myocardial histopathology with clinical characteristics of patients with obstructive HCM and post-operative outcomes following septal myectomy.MethodsThe authors reviewed the pathological findings of the myocardial specimens from 1,836 patients with obstructive HCM who underwent septal myectomy from 2000 to 2016. Myocyte hypertrophy, myocyte disarray, interstitial fibrosis, and endocardial thickening were graded and analyzed.ResultsThe median age at operation was 54.2 years (43.5 to 64.3 years), and 1,067 (58.1%) were men. A weak negative correlation between myocyte disarray and age at surgery was identified (ρ = ?0.22; p < 0.001). Myocyte hypertrophy (p < 0.001), myocyte disarray (p < 0.001), and interstitial fibrosis (p < 0.001) were positively associated with implantable cardioverter-defibrillator implantation. Interstitial fibrosis (p < 0.001) and endocardial thickening (p < 0.001) were associated with atrial fibrillation pre-operatively. In the Cox survival model, older age (p < 0.001), lower degree of myocyte hypertrophy (severe vs. mild hazard ratio: 0.41; 95% confidence interval: 0.19 to 0.86; p = 0.040), and lower degree of endocardial thickening (moderate vs. mild hazard ratio: 0.75; 95% confidence interval: 0.58 to 0.97; p = 0.019) were independently associated with worse post-myectomy survival. Among 256 patients who had genotype analysis, patients with pathogenic or likely pathogenic variants (n = 62) had a greater degree of myocyte disarray (42% vs. 15% vs. 20%; p = 0.022). Notably, 13 patients with pathogenic or likely pathogenic genetic variants of HCM had no myocyte disarray.ConclusionsHistopathology was associated with clinical manifestations including the age of disease onset and arrhythmias. Myocyte hypertrophy and endocardial thickening were negatively associated with post-myectomy mortality.