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, Pmax and Pmin , 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, QTc 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.

Effect of Short-Term L-Thyroxine Therapy on Left Ventricular Mechanics in Idiopathic Dilated Cardiomyopathy.

OBJECTIVE: Previous experimental studies have provided evidence of notable changes in thyroid hormone signaling that corresponds to alterations in myocardial function in animal models of heart failure (HF). The present study further explores whether oral thyroid hormone treatment can change left ventricular (LV) mechanics and functional status in patients with idiopathic dilated cardiomyopathy (IDCM) or not. METHODS: Sixty IDCM patients who were receiving conventional HF treatment were randomized to oral L-thyroxine (n = 40) or placebo (n = 20) for 3 months. Fifty-two (86.7%) of all IDCM patients were symptomatic, their mean age was 41 ± 12 years, and their ejection fraction was 32% ± 7%. At baseline, the two groups were comparable in clinical and echocardiographic variables. Vector velocity imaging was utilized to assess LV mechanics. Myocardial longitudinal peak systolic strain, systolic strain rate, early and late diastolic strain rate, circumferential strain, LV dyssynchrony, plasma tri-iodothyronine, thyroxine, and thyroid stimulating hormone levels were measured at baseline and 3 months after treatment. RESULTS: All patients receiving L-thyroxine significantly improved in functional status (New York Heart Association class; P < .001) and echocardiographic parameters including end-diastolic diameter (P < .001), end-systolic diameter (P < .001), mitral regurgitation severity reduction (P < .001), and increased ejection fraction (P < .001). Left ventricular mechanics showed marked improvement at segmental and global levels of both longitudinal and circumferential myocardial strain (P < .005) when compared with placebo group. CONCLUSIONS: Short-term L-thyroxine therapy is well tolerated in IDCM patients. It improves cardiac mechanics and functional status, which might support the potential role of synthetic thyroid hormones in HF treatment.

Clinical characteristics and in-hospital outcome of heart failure in women: a single center registry from Egyptian cardiac care unit.

BACKGROUND: This study represents figures from a cardiac care unit (CCU) of a university hospital; it describes an example of a tertiary academic center in Egypt and provides an epidemiological view of the female HF patients, their risk profile, and short-term outcome during hospitalization. RESULTS: It is a local single-center cross-sectional observational registry of CCU patients 1 year from July 2015 to July 2016. Patient's data were collected through a special software program. Women with evidence of HF were thoroughly studied. Among the 1006 patients admitted to CCU in 1 year, 345 (34.2%) patients were females and 118 (34.2%) had evidence of HF, whereas 661 (65.7%) were males and 178 (26.9%) of them had HF. Women with HF showed 11.7% prevalence of the total population admitted to CCU. 72.7% were HFrEF and 27.3% were HFpEF. Compared to men, women with HF were older in age, more obese, less symptomatic than men, had higher incidence of associated co-morbidities, less likely to be re-admitted for HF, and less likely to have ACS and PCI. Valvular heart diseases and cardiomyopathies were the commonest etiologies of their HF. Women had more frequent normal ECG, higher EF%, and smaller LA size. There is no difference in medications and CCU procedures. While females had shorter stay, there is no significant difference in hospital mortality compared to male patients. CONCLUSIONS: Despite higher prevalence of HF in females admitted to CCU and different clinical characteristics and etiology of HF, female gender was associated with similar prognosis during hospital course compared to male gender.

Prognostic significance of left ventricular end diastolic pressure using E/E' in patients with hypertrophic cardiomyopathy.

BACKGROUND: Left ventricular (LV) diastolic dysfunction is a prominent feature of hypertrophic cardiomyopathy (HCM). Prediction of LV filling pressure using the ratio between early diastolic transmitral flow and mitral annular velocity (E/e') had proved a good accuracy. AIM OF THIS STUDY: We investigated the value of E/e' to predict cardiovascular (CV) mortality in patients with HCM. METHODS: A total of 243 patients with HCM had E/e' measured in combination with clinical evaluation, conventional echocardiographic measurements, cardiopulmonary exercise evaluation, and Holter monitoring. RESULTS: During a mean follow-up of (3.2 ± 1.2 years), 17 (7%) patients died. Non survivors had significantly higher SBP, DBP, left ventricular outflow tract obstruction (LVOTO) gradient, mitral E, and E/e', but lower e' of mitral annulus and more prevalent restrictive filling pattern. E/e' was directly correlated with age (r = .24, P < .005), left atrial volume index (r = .44, P < .0001), LVMI (r=0.23,P<.005), LVOT gradient (r = .43, P < .0001), NYHA class (r = .19, P < .006), pulmonary artery pressure (r = .24, P < .005), positive family history of HCM (r = .22, P < .005), and inversely related to peak systolic velocity (S) (r = .44, P < .0001). By multivariate analysis, only LVOTO ([RR] 4.11, 95% CI 1.002 to 1.148, P < .04) and E/e' were independent predictors for overall mortality in HCM (relative risk [RR] 5.27, 95% CI 1.002 to 1.024, P < .02). The risk of dying increased with increasing E/e' ratio, being approximately 4 times higher for patients in the highest quartile (HR 3.8 (CI 1.38-5.12, log-rank < 0.002)). CONCLUSIONS: In hypertrophic cardiomyopathy, the E/e' ratio remains a powerful predictor of all-cause mortality, particularly if it is associated with LVOT obstruction.

Comparison of vector velocity imaging and three-dimensional speckle tracking echocardiography for assessment of left ventricular longitudinal strain in hypertrophic cardiomyopathy.

Background: Vector velocity imaging (VVI) is a two-dimensional wall motion tracking method that can measure cardiac mechanics in hypertrophic cardiomyopathy (HCM). 3D-speckle tracking echocardiography (3D-STE) has been proven to be superior to conventional measures in assessment of LV function. The aim of this study was to compare the two technologies in the assessment of LV longitudinal strain (LS) in HCM patients. Methods: A total of 50 patients with HCM were investigated using VVI and 3D-STE in same setting. 3D-STE allows obtaining longitudinal, circumferential, radial and area strains (AS). Values of longitudinal strain (LS) and AS by 3D-STE were compared to VVI- derived analyses. Thereafter, VVI-LS values were correlated with LV phenotype. Last, the variability of VVI versus 3DE strain measurements as well as recorded time of analysis was assessed. Results: The absolute value of 3D-STE LS and AS is significantly higher than VVI-LS (P < 0.0001). VVI provided complete longitudinal LV strain information, similar to 3D-STE. There is excellent agreement between the two technologies-derived values, however, a greater number of segments could be analyzed using VVI (94.7%), compared with 3DE (62.1%). Despite VVI being more time consuming, VVI-LS is more correlated to LV mass index, mitral regurgitation severity and functional class when compared with 3D-STE LS and AS. Conclusions: VVI is a feasible modality for assessing LV longitudinal strain. Although VVI agreed well with 3D-STE for most of regional and global LS, a better correlation was found between VVI-LS and HCM phenotype. It is hypothesized that this discrepancy originates from the inferior imaging quality using 3D tracking algorithms.

Relationship of left atrial mechanics to electrical activity on surface electrocardiography in idiopathic dilated cardiomyopathy.

Aim: (1) Assess left atrial (LA) mechanics and electromechanical delay in patients with idiopathic dilated cardiomyopathy (IDCM), and (2) examine the relationship between atrial electromechanical delay and atrial electrical activity [P-wave duration, P-wave dispersion (PWD) and P terminal force (PTF)] on surface ECG. Methods: 73 IDCM patients (age 36  ±  17 years); 63% men,25 age & sex matched healthy subjects were studied. LA atrial electromechanical delay & mechanics (εsys, SRsys, SRe, SRa) were measured with 2D-strain. From 12-lead electrocardiograms, P-wave duration, PWD and PTF calculated. Results: Reservoir, conduit and contractile functions were predominantly reduced compared to control (P < 0.001). Intra-atrial electromechanical delay was 88.9 ± 84.6 in IDCM versus 27.4 ± 16.5 in control (P < 0.0001). In IDCM, PWD (52.89 ± 15), Pmax(98 ± 17.5) and PTF(58.2 ± 36) were significantly increased compared to control (36.20 ± 8.9, 79 ± 9.9, 25.22 ± 8.76) respectively (P < 0.0001). A positive correlation was detected between intra-atrial electromechanical delay and PWD &PTF (r = 0.5, P < 0.0001). By stepwise multiple linear regression analyses, LA reservoir function (LA εsys) [ß = 0.754; CI at 95%:0.356-0.780, P < 0.001] and LA volume [ß = 0.743; CI 95%:0.423-0.75, P < 0.001], and PWD [ß=0.848; CI 95%:0.311-0.644, P < 0.0001], and PTF [ß = 0.927; CI 95%: 0.357-0.722, P < 0.0001] are independent predictors for LA electromechanical delay in IDCM. Conclusion: In addition to altered LA mechanics, atrial electromechanical delay gets longer in IDCM and is correlated with PWD and PTF. Atrial electrical dispersion on surface ECG could be early index of LA dysfunction that deserves further study.

Characterization of Left Atrial Mechanics in Hypertrophic Cardiomyopathy and Essential Hypertension Using Vector Velocity Imaging.

BACKGROUND: Systemic hypertension (HTN) and hypertrophic cardiomyopathy (HCM) may be associated with left atrial (LA) dilation, but whether LA functional abnormalities are characteristic to each disease or not, is unknown. The aim of this study was to characterize LA mechanical changes in patients with HTN and HCM using vector velocity imaging (VVI). METHODS: VVI-derived longitudinal LA function was acquired from apical views in 76 CM patients, 33 hypertension patients and 30 age-matched controls. Peak atrial longitudinal strain (ɛsys ), atrial strain rate during systole (SRsys ), early diastole (SRe ), and late diastole (SRa ) were measured (corresponding to LA reservoir, conduit and contractile functions, respectively). Similar parameters were used to assess left ventricular (LV) function. RESULTS: LV mass and LA volume index were higher in HCM and HTN than in controls. Both LA Reservoir function (LA ɛsys SRsys ) and conduit function (SRe ) were more declined in HCM patients, in comparison to HTN patients and controls (P < 0.0001),whereas conduit function was the only function deteriorated in the HTN group. LA contractile function was preserved among patient groups. In HCM, LV ɛsys and SRa [P < 0.001] are independent predictors for LA ɛsys . While in hypertension, only LVMI is an independent predictor for LA dysfunction (P < 0.01). By receiver operating characteristic analyses, only atrial reservoir function was extrapolative and appeared to be accurate in discriminating HCM from both hypertension and controls, with LA ɛsys ≤ 33% being more sensitive (71.8%) and specific (75%). CONCLUSIONS: Response of LA mechanics to pathologic hypertrophy is entirely different. In HCM LA reservoir and conduit functions are more deteriorated and related to the severity of phenotype, while in hypertension the conduit function is chiefly affected and LA dysfunction is linked to a more advanced disease.

Provocation of left ventricular outflow tract obstruction using nitrate inhalation in hypertrophic cardiomyopathy: Relation to electromechanical delay.

BACKGROUND: Left ventricular outflow tract obstruction (LVOT) is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). It is of major importance that the provocation modalities used are validated against each other. AIM: To define the magnitude of LVOT gradients provocation during both isosorbide dinitrate (ISDN) inhalation and treadmill exercise in non-obstructive HCM and analyze the correlation to the electromechanical delay using speckle tracking. METHODS: We studied 39 HCM pts (64% males, mean age 38 ± 13 years) regional LV longitudinal strain and electromechanical delay (TTP) was analyzed at rest using speckle tracking. LVOT gradient was measured at rest and after ISDN then patients underwent a treadmill exercise echocardiography (EE) and LVOT gradient was measured at peak exercise. RESULTS: The maximum effect of ISDN on LVOT gradient was obtained at 5 minutes, it increased to a significant level in 12 (31%) patients, and in 14 (36%) patients using EE, with 85.6% sensitivity & 100% specificity. Patients with latent obstruction had larger left atrial volume and lower E/A ratio compared to the non-obstructive group (p < 0.01). LVOTG using ISDN was significantly correlated with that using EE (p < 0.0001), resting LVOTG (p < 0.0001), SAM (p < 0.0001), EF% (p < 0.02) and regional electromechanical delay but not related to global LV longitudinal strain. Using multivariate regression, resting LVOTG (p = 0.006) & TTP mid septum (p = 0.01) were found to be independent predictors of latent LVOT obstruction using ISDN. CONCLUSION: There is a comparable diagnostic value of nitrate inhalation to exercise testing in provocation of LVOT obstruction in HCM. Latent obstruction is predominantly dependent on regional electromechanical delay.

Systolic function reserve using two-dimensional strain imaging in hypertrophic cardiomyopathy: comparison with essential hypertension.

BACKGROUND: Although patients with hypertrophic cardiomyopathy (HCM) have normal ejection fractions at rest, the investigators hypothesized that these patients have differentially abnormal systolic function reserves, limiting their exercise capacity compared with patients with hypertension (HTN). METHODS: Forty patients with HCM (mean age, 39.1 ± 12 years), 20 patients with HTN with LVH, and 33 healthy individuals underwent resting and peak exercise echocardiography using two-dimensional strain imaging. Peak longitudinal systolic strain (εsys) and strain rate were measured in apical views. Circumferential εsys and left ventricular (LV) twist were analyzed from short-axis views. LV systolic dyssynchrony was measured from regional longitudinal strain curves as the standard deviation of time to peak strain (time from the beginning of the Q wave on electrocardiography to peak εsys) between 12 segments. The differences between resting and peak exercise values were analyzed, and functional reserve was calculated as the difference divided by the resting value. RESULTS: In patients with HCM, resting values for longitudinal εsys, systolic strain rate, early diastolic strain rate, and atrial diastolic strain rate were significantly lower, while circumferential εsys and twist were higher, compared with patients with HTN and controls (P < .0001). Functional systolic reserve increased during exercise in controls (17 ± 6%), increased to a lesser extent in patients with HTN (10 ± 16%), and was markedly attenuated in patients with HCM (-23 ± 28%) (P < .001). At peak exercise, even with augmented circumferential εsys and twist in patients with HCM (P < .01) compared with those with HTN, both remained lower than in controls (P < .001). LV dyssynchrony was amplified during exercise in patients with HCM compared with those with HTN (P < .001). Within the entire population, exercise capacity was clearly correlated with systolic functional reserve. However when taken separately, it was mainly related to resting LV dyssynchrony and diastolic function in patients with HCM, whereas it was linked to age and LV wall thickness in those with HTN. CONCLUSIONS: Patients with HCM have significantly limited systolic function reserve and more dynamic dyssynchrony with exercise compared with those with HTN. Two-dimensional strain imaging during stress may provide a new and reliable method to identify patients at higher cardiovascular risk.

Changes in left atrial deformation in hypertrophic cardiomyopathy: Evaluation by vector velocity imaging.

OBJECTIVES: Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. We assessed the global and regional left atrial (LA) function and its relation to left ventricular (LV) mechanics and clinical status in patients with HCM using Vector Velocity Imaging (VVI). METHODS: VVI of the LA and LV was acquired from apical four- and two-chamber views of 108 HCM patients (age 40 ± 19years, 56.5% men) and 33 healthy subjects, all had normal LV systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ϵ)/strain rate (SR) measurements. RESULTS: Left atrial reservoir (ϵsys,SRsys) and conduit (early diastolic SRe) function were significantly reduced in HCM compared to controls (P < .0001). Left atrial deformation directly correlated to LVϵsys, SRsys and negatively correlated to age, NYHA class, left ventricular outflow tract (LVOT) gradient, left ventricular mass index (LVMI), LA volume index and severity of mitral regurge (P < 0.001). Receiver operating characterist was constructed to explore the cutoff value of LA deformation in differentiation of LA dysfunction; ϵsys < 40% was 75% sensitive, 50% specific, SRsys < 1.7s(- 1) was 70% sensitive, 61% specific, SRe> - 1.8s(- 1) was 81% sensitive and 30% specific, SRa> - 1.5s(- 1) was 73% sensitive and 40% specific. By multivariate analysis global LVϵsys and LV septal thickness are independent predictors for LAϵsys, while end systolic diameter is the only independent predictor for SRsys, P < .001. CONCLUSION: Left atrial reservoir and conduit function as measured by VVI were significantly impaired while contractile function was preserved among HCM patients. Left atrial deformation was greatly influenced by LV mechanics and correlated to severity of phenotype.