Satoshi Yuda

Echocardiographic detection of early diabetic myocardial disease

OBJECTIVES We sought to determine whether disturbances of myocardial contractility and reflectivity could be detected in diabetic patients without overt heart disease and whether these changes were independent and incremental to left ventricular hypertrophy (LVH). BACKGROUND Left ventricular (LV) dysfunction is associated with diabetes mellitus, but LVH is common in this population and the relationship between diabetic LV dysfunction and LVH is unclear. METHODS We studied 186 patients with normal ejection fraction and no evidence of CAD: 48 with diabetes mellitus only (DM group), 45 with LVH only (LVH group), 45 with both diabetes and LVH (DH group), and 48 normal controls. Peak strain and strain rate of six walls in apical four-chamber, long-axis, and two-chamber views were evaluated and averaged for each patient. Calibrated integrated backscatter (IB) was assessed by comparison of the septal or posterior wall with pericardial IB intensity. RESULTS All patient groups (DM, DH, LVH) showed reduced systolic function compared with controls, evidenced by lower peak strain (p < 0.001) and strain rate (p = 0.005). Calibrated IB, signifying myocardial reflectivity, was greater in each patient group than in controls (p < 0.05). Peak strain and strain rate were significantly lower in the DH group than in those in the DM alone (p < 0.03) or LVH alone (p = 0.01) groups. CONCLUSIONS Diabetic patients without overt heart disease demonstrate evidence of systolic dysfunction and increased myocardial reflectivity. Although these changes are similar to those caused by LVH, they are independent and incremental to the effects of LVH.

Diabetic cardiomyopathy: pathophysiology and clinical features

Since diabetic cardiomyopathy was first reported four decades ago, substantial information on its pathogenesis and clinical features has accumulated. In the heart, diabetes enhances fatty acid metabolism, suppresses glucose oxidation, and modifies intracellular signaling, leading to impairments in multiple steps of excitation–contraction coupling, inefficient energy production, and increased susceptibility to ischemia/reperfusion injury. Loss of normal microvessels and remodeling of the extracellular matrix are also involved in contractile dysfunction of diabetic hearts. Use of sensitive echocardiographic techniques (tissue Doppler imaging and strain rate imaging) and magnetic resonance spectroscopy enables detection of diabetic cardiomyopathy at an early stage, and a combination of the modalities allows differentiation of this type of cardiomyopathy from other organic heart diseases. Circumstantial evidence to date indicates that diabetic cardiomyopathy is a common but frequently unrecognized pathological process in asymptomatic diabetic patients. However, a strategy for prevention or treatment of diabetic cardiomyopathy to improve its prognosis has not yet been established. Here, we review both basic and clinical studies on diabetic cardiomyopathy and summarize problems remaining to be solved for improving management of this type of cardiomyopathy.

Influence of wall stress and left ventricular geometry on the accuracy of Dobutamine stress Echocardiography

OBJECTIVE The goal of this study was to determine whether wall stress at rest and during stress could explain the influence of left ventricular (LV) morphology on the accuracy of dobutamine stress echocardiography (DSE). BACKGROUND The sensitivity of DSE appears to be reduced in patients with concentric remodeling, but the cause of this finding is unclear. METHODS We studied 161 patients without resting wall motion abnormalities who underwent DSE and coronary angiography. Patients were classified into four groups according to relative wall thickness (normal <0.45) and LV mass (normal </=131 g/m(2) in men and </=100 g/m(2) in women): normal geometry, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Significant coronary artery disease was defined as >/=50% stenosis. Circumferential (cESS) and meridional end-systolic wall stress (mESS) were calculated at rest and peak DSE. RESULTS Both false-negative and false-positive results for DSE were present in 35 patients (22%). The accuracy of DSE in patients with concentric remodeling (61%) was lower than that in patients with normal geometry (85%, p < 0.05) or concentric hypertrophy (86%, p < 0.05), but the accuracy with eccentric hypertrophy (64%, p < 0.05) was lower than with concentric hypertrophy. Patients in lowest quartile of cESS and mESS at peak had significantly lower sensitivity and accuracy than those in the highest quartile. A reduced cESS at peak (p = 0.012), presence of concentric remodeling (p = 0.044), and eccentric hypertrophy (p = 0.012) were significant predictors of both false-negative and false-positive results for DSE. CONCLUSIONS The accuracy of DSE is influenced by the LV geometric pattern and peak wall stress.

Clinical implications of midventricular obstruction and intravenous propranolol use in transient left ventricular apical ballooning (Tako-tsubo cardiomyopathy)

BACKGROUND Persistent hypotension with dynamic midventricular obstruction (MVO) in patients with transient left ventricular (LV) apical ballooning (Tako-tsubo cardiomyopathy) is an important complication that needs to be treated. PURPOSE The objective of this study is to determine the effects of intravenous propranolol challenge on MVO in transient LV apical ballooning. SUBJECTS AND METHODS Thirty-four patients (12 males, 22 females, mean age 64 +/- 17 years, age range 22-84 years) with LV apical ballooning were enrolled. The hemodynamic and echocardiographic effects of propranolol (0.05 mg/kg, maximum 4 mg) were analyzed in 13 patients. RESULTS (1) Midventricular obstruction was present in 8 (24%) of 34 patients, and the pressure gradient (PG) ranged from 28 to 140 mm Hg. (2) Patients with MVO had similar demographic and clinical characteristics (symptoms, peak creatine kinase, plasma catecholamine levels) as those without MVO; however, in patients with MVO, abnormal Q waves on electrocardiogram and hypotension were more prevalent. (3) In the MVO group, intravenous propranolol changed the PG from 90 +/- 42 to 22 +/- 9 mm Hg, the systolic blood pressure (SBP) from 85 +/- 11 to 116 +/- 20 mm Hg, and the LV ejection fraction (LVEF) from 30% +/- 7% to 43% +/- 4%. (4) In all subjects, the changes in the PG after propranolol injection had a significant linear correlation with the SBP and LVEF changes: deltaSBP = 4.738 + 0.315 x deltaPG (r = 0.689 (P < .001) and deltaLVEF = 2.973 + 0.1321 x deltaPG (r = 0.715, P < .001). CONCLUSION Intravenous propranolol is useful for treating dynamic MVO in patients with transient LV apical ballooning.

Quantitative assessment of left ventricular and left atrial functions by strain rate imaging in diabetic patients with and without hypertension.

Background: Impaired left ventricular (LV) function is shown by strain rate (SR) imaging in patients with diabetes mellitus (DM). Left atrium (LA) function in patients with DM, however, has not been assessed by this method and the effect of hypertension (HT) on LV and LA functions in diabetic patients has not been fully studied. The aim of this study was to quantitatively assess LA function in diabetic patients with and without HT in combination with LV function. Methods: Conventional echocardiographic and SR imaging studies were performed in 55 subjects with normal systolic LV function (LV ejection fraction of 55% or more) and no evidence of coronary artery disease: 17 with DM (DM group), 22 who have both DM and HT (DM+HT group), and 16 age‐matched controls. SR imaging was performed from three apical views, and peak SR was measured at 12 LV segments and 5 LA segments. Mean peak systolic SR (LVs and LAs, respectively), early diastolic SR (LVe and LAe, respectively) and late diastolic SR (LVa and LAa, respectively) were calculated by averaging data in each LV and LA segment. Results: Despite no significant differences in age, LV ejection fraction and E/A ratio among the three groups, systolic blood pressure, LA dimension and LV mass index in the DM+HT group were significantly larger than those in the controls. The DM group had reduced systolic and diastolic LV functions and impaired LA reservoir and conduit functions compared with those in the controls, as shown by lower LVs (P < 0.05), LVe (P < 0.01), LAs (P < 0.01), and LAe (P < 0.05). The DM+HT group had reduced LVs (P < 0.01), LVe (P < 0.01), LAs (P < 0.01) and LAe (P < 0.01) compared with those in the controls. The DM+HT group had significantly lower LVe (P < 0.05) and LAe (P < 0.05) than did the DM group. Conclusions: SR imaging can detect impairment of LA reservoir and conduit functions as well as LV systolic and diastolic dysfunctions in patients with DM, even in the absence of LV hypertrophy and LA dilatation. Coexisting HT augments the impairment of LV diastolic and LA conduit functions in diabetic patients.

Left Ventricular Hypertrophy Causes Different Changes in Longitudinal, Radial, and Circumferential Mechanics in Patients with Hypertension: A Two-Dimensional Speckle Tracking Study

BACKGROUND Systolic reserve is an important compensatory mechanism against increasing afterload. Although longitudinal systolic dysfunction with preserved ejection fraction has been reported in hypertensive hearts, radial and circumferential function has not been fully examined. The aim of this study was to investigate three-directional systolic function and its relationships with left ventricular geometry in asymptomatic hypertensive patients using two-dimensional speckle-tracking imaging. METHODS Echocardiographic evaluations were performed in 74 hypertensive patients and 55 age-matched control subjects. RESULTS Longitudinal strain was significantly reduced in the hypertrophy groups compared with that in control subjects (concentric, -15.1 ± 4.0%; eccentric, -15.9 ± 4.4%; control, -18.9 ± 3.3%; P < .05). Conversely, radial strain was significantly higher in the normal geometry group than in control subjects (53.8 ± 19.4% vs 40.3 ± 15.1%, P < .05). However, this augmentation was attenuated in the other geometries. CONCLUSION Hypertrophic remodeling attenuates compensatory augmentation of radial systolic function and is associated with latent longitudinal systolic dysfunction.

Impaired Cardiac Sympathetic Innervation and Myocardial Perfusion Are Related to Lethal Arrhythmia: Quantification of Cardiac Tracers in Patients with ICDs

Despite widespread prophylactic use of implantable cardioverter defibrillator (ICD) therapy, sudden cardiac death and refractory arrhythmia events are still important clinical issues to be overcome. We examined whether the impairment of cardiac sympathetic innervation and myocardial perfusion is responsible for lethal arrhythmic events and has prognostic value by comparing conventional clinical indices. Methods: In consecutive ICDs implanted in 60 patients, cardiac uptake of 123I-metaiodobenzylguanidine and 99mTc-tetrofosmin at rest was quantified, and then patients were prospectively followed with endpoints of appropriate ICD shocks or cardiac death. Cardiac metaiodobenzylguanidine activity was quantified as a heart-to-mediastinum ratio (HMR), and impaired tetrofosmin uptake was graded as a summed score (SS) using a computerized technique with a percentage of tracer uptake. Results: During a mean 29-mo interval, ICD shock was documented in 30 patients (50%); 3 cardiac deaths were also observed in this group of patients. Patients with ICD shocks had a significantly smaller HMR and a greater SS than did those without (1.73 ± 0.34 vs. 2.06 ± 0.46, P = 0.003, and 18.0 ± 16.2 vs. 5.7 ± 4.4, P = 0.001, respectively). Kaplan–Meier analysis showed that patients who had both an HMR of 1.90 or less and an SS of 12 or greater had a significantly greater ICD discharge rate than did those who had both an HMR greater than 1.90 and an SS less than 12 (94% vs. 18%, P < 0.005) (log rank, 15.14; P < 0.0005). Multivariate analysis with a Cox model identified the greatest Wald χ2 of 6.454 and a hazard ratio of 3.857 (P = 0.011) when an HMR of 1.9 or less and tetrofosmin SS of 12 or greater were combined. Conclusion: Impairment of cardiac sympathetic innervation and myocardial perfusion is related to lethal arrhythmic events leading to sudden death, and the combined assessment of these can identify patients for whom prophylactic ICD use has the greatest potential.

Long-term follow-up of atrial contraction after the maze procedure in patients with mitral valve disease

OBJECTIVES We sought to determine the effectiveness of the maze procedure for maintaining sinus rhythm and atrial contraction for a long period in patients with mitral valve disease. BACKGROUND Although the maze procedure for atrial fibrillation (AF) has been effective in restoring sinus rhythm in patients with mitral valve disease, the long-term results of this procedure have not been determined. METHODS We echocardiographically studied 94 consecutive patients with mitral valve disease before, as well as early (3.1 +/- 3.3 months) and late (2.2 +/- 0.9 years) after, the maze procedure. Peak velocity and the time-velocity integral of the left ventricular (LV) diastolic filling wave during atrial contraction (A wave), as well as the atrial filling fraction (calculated as the ratio of the time-velocity integral of the A wave to total diastolic filling), were obtained from transmitral flow recordings. Peak A wave velocity > or =10 cm/s was considered to indicate echocardiographic evidence of effective atrial contraction. RESULTS Regular rhythm with P waves was restored in 70 patients (74%) in the early stage and in 59 patients (63%, p = 0.09) in the late stage after the maze procedure. Forty-seven patients (50%) in the early stage and 36 patients (38%, p = 0.14) in the late stage showed effective atrial contraction by Doppler echocardiography. Left atrial (LA) and LV end-diastolic diameters significantly decreased after the procedure (from 59 +/- 13 to 48 +/- 7 mm, p < 0.01; and from 54 +/- 9 to 47 +/- 5 mm, p < 0.01, respectively) and did not show significant changes during the follow-up period. Once atrial contraction was resumed, its degree did not change between the early and late stages after the maze procedure (17 +/- 6% vs. 17 +/- 6% for atrial filling fraction). CONCLUSIONS Sinus rhythm and atrial contraction recovered early after the maze procedure in most patients and were maintained for more than two years. Once active atrial contraction was resumed, the degree of contraction did not change thereafter. These results demonstrate that the maze procedure is effective for a long period in patients with mitral valve disease.

Normal values and clinical relevance of left atrial myocardial function analysed by speckle-tracking echocardiography: multicentre study

AIMS The aim of this multicentre study was to determine the normal range and the clinical relevance of the myocardial function of the left atrium (LA) analysed by 2D speckle-tracking echocardiography (2DSTE). METHODS AND RESULTS We analysed 329 healthy adult subjects prospectively included in 10 centres and a validation group of 377 patients with left ventricular diastolic dysfunction (LVDD). LA myocardial function was analysed by LA strain rate peak during LA contraction (LA-SRa) and LA strain peak during LA relaxation (LA-Strain). The range of values of LA myocardial function in healthy subjects was LA-SRa -2.11 ± 0.61 s(-1) and LA-Strain 45.5 ± 11.4%, and the lowest expected values of these LA analyses (calculated as -1.96 SD from the mean of healthy subjects) were LA-SRa -0.91 s(-1) and LA-Strain 23.1%. Concerning the clinical relevance of these LA myocardial analyses, LA-SRa and LA-Strain detected subtle LA dysfunction in patients with LVDD, even though LA volumetric measurements were normal. In addition, in these patients we found that the functional class (dyspnoea-NYHA classification) was inversely related to both LA-Strain and LA-SRa. CONCLUSION In the present multicentre study analysing a large cohort of healthy subjects and patients with LVDD, the normal range and the clinical relevance of the myocardial function of the LA using 2DSTE have been determined.

Comparative Efficacy of the Maze Procedure for Restoration of Atrial Contraction in Patients With and Without Giant Left Atrium Associated With Mitral Valve Disease

OBJECTIVES We sought to determine the effectiveness of the maze procedure for restoring atrial contraction in patients with and without giant left atrium (GLA). BACKGROUND Although the maze procedure has been reported to be effective for refractory atrial fibrillation, it is unknown whether this procedure can restore effective atrial contraction in patients with GLA. METHODS Nineteen patients with and 32 patients without GLA were studied with Doppler echocardiography before and after the maze procedure. Peak velocity and the time-velocity integral of the left ventricular diastolic filling wave during atrial contraction (A wave) and the atrial filling fraction calculated as the ratio of the time-velocity integral of the A wave to that of total diastolic filling were compared between patients with and without GLA. A peak A wave velocity > or =10 cm/s was considered to indicate echocardiographic evidence of effective atrial contraction. RESULTS Regular rhythm with P waves was restored in 10 patients (53%) with and 26 (81%, p < 0.05) without GLA. Four patients (21%) with and 21 patients (66%, p < 0.01) without GLA showed effective atrial contraction by echocardiography. Once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA (17+/-5% vs. 17+/-4% for atrial filling fraction at 12 months, respectively). CONCLUSIONS Although most patients without GLA had restored atrial contraction by the maze procedure, it was resumed in fewer patients with GLA. However, once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA. Therefore, the maze procedure may be an option in selected patients with GLA.