Myocardial ultrasonic tissue characterization in pediatric and adult patients with hypertrophic cardiomyopathy

"Speckled" ventricular septum in hypertrophic cardiomyopathy revisited after 30 years

We found a highly inconsistent relation between the granular and reflective ultrasound ("speckling") pattern frequently observed in the ventricular septum of patients with hypertrophic cardiomyopathy and evidence of myocardial fibrosis by contrast-enhanced cardiovascular magnetic resonance imaging. Therefore, this distinctive echocardiographic appearance of the myocardium does not accurately characterize left ventricular scarring and is most likely explained as an extraneous ultrasound signal pattern. In conclusion, myocardial fibrosis in patients with hypertrophic cardiomyopathy is most reliably identified using contrast-enhanced cardiovascular magnetic resonance imaging.

Myocardial Texture in Hypertrophic Cardiomyopathy

BACKGROUND

This study was conceived to assess associations between integrated backscatter signal at end diastole (IBS) and diastolic properties in patients with hypertrophic cardiomyopathy.

METHODS

In 46 patients with hypertrophic cardiomyopathy, septal IBS was calculated by both applying an appropriate regression correction (IBSc) and by relating it to pericardial reflectivity (IBSp). Difference in duration between transmitral forward and pulmonary venous backward velocities (A-Ar) was measured as an estimate of passive diastolic filling. In all, 38 patients underwent ambulatory electrocardiogram monitoring for 48 hours.

RESULTS

IBS inversely correlated to both A-Ar (IBSc, r = -.522, P < .001; IBSp, r = -.302, P = .041) and mitral peak velocity at atrial contraction (IBSc, r = -.464, P = .002; IBSp, r = -.413, P = .004). Moreover, IBS was greater in patients with sustained or nonsustained ventricular tachycardia (IBSc, 28.5 +/- 3.8 vs 25.4 +/- 3.8 dB, P = .034).

CONCLUSIONS

Septal IBS correlates with Doppler parameters of left ventricular chamber stiffness in patients with hypertrophic cardiomyopathy. Increased IBS is associated with presence of ventricular arrhythmias.

Changes in cardiac tissue characterization in carriers with gene mutations associated with hypertrophic cardiomyopathy

BACKGROUND

Early detection in patients with hypertrophic cardiomyopathy (HCM) is very important. Integrated backscatter (IB) provides a useful noninvasive measure of the acoustic properties of the myocardium, and may detect early myocardial changes.

METHODS

Thirty-four carriers who had gene mutations causing HCM were studied. The patients were divided into three groups as follows: (1) 21 patients with wall hypertrophy (Group A), (2) 7 patients with ECG abnormalities but without wall hypertrophy (Group B), and (3) 6 carriers with neither ECG abnormalities nor wall hypertrophy (Group C). All subjects underwent ECG, conventional echocardiography and acoustic densitometry. In addition, we studied subjects < or =20 years old from Groups B and C (Group B-2 and Group C-2, respectively), and compared them with control subjects with no cardiac disorders who were < or =20 years old.

RESULTS

In Group A, cyclic variations of integrated backscatter (CV-IB) in the interventricular septum and left ventricular posterior wall were significantly smaller than in Group C. The amplitude of IB in the interventricular septum and left ventricular posterior wall in Group A was significantly higher than those in Group C. Even in Group B, CV-IB in the interventricular septum was significantly smaller than those in Group C. Among patients < or =20 years old, CV-IB in the interventricular septum was significantly smaller in Group B-2 than in control subjects, while that in Group C-2 did not differ from that in control subjects.

CONCLUSIONS

Changes in tissue characterization were found in the hearts of HCM gene carriers even in the absence of wall hypertrophy. These results suggest that tissue changes detectable by the acoustic densitometry methods may occur in the hearts of HCM gene carriers without wall hypertrophy, and that they may be detectable at the time of appearance of ECG abnormalities.

Early myocardial abnormalities in asymptomatic patients with severe isolated congenital aortic regurgitation: An ultrasound tissue characterization and strain rate study

BACKGROUND

Aortic valve regurgitation (AR) in the pediatric population has increased in recent years because of the expanded use of new surgical and hemodynamic procedures. Unlike adult patients, few predictors for the need of operation have been proposed in young asymptomatic or mildly symptomatic patients with AR.

METHODS

To unmask early abnormalities of left ventricular (LV) function, 59 participants were enrolled: 14 asymptomatic patients (mean age 18 years) with congenital isolated severe AR and normal LV function (LV ejection fraction > 50%); and 45 healthy control subjects with comparable age and body surface area. All the studied population underwent standard echocardiographic examination, integrated backscatter, and strain rate imaging study.

RESULTS

Conventional echocardiographic indices of global LV systolic performance for patients with AR were similar to that of control subjects. Compared with control subjects, integrated backscatter analysis demonstrated a significant reduction in cyclic variation in both septal and posterior walls ( P < .05). LV radial and longitudinal deformation properties for patients with AR were significantly reduced ( P < .05) as assessed by peak systolic strain rate.

CONCLUSION

Our results demonstrated the ability of integrated backscatter and strain rate imaging to detect early subclinical abnormalities in young patients with severe congenital AR despite the presence of a normal ejection fraction.

Myocardial ultrasound tissue characterization in patients with hypertrophic cardiomyopathy: noninvasive evidence of electrical and textural substrate for ventricular arrhythmias

BACKGROUND

Although in patients with hypertrophic cardiomyopathy (HCM) pathologic studies seem to suggest a correlation between morphologic findings and arrhythmias, it has never been confirmed in the clinical setting.

OBJECTIVE

We sought to noninvasively assess the electrical and textural properties of the myocardium and to define their potential relationship in patients with HCM.

METHODS

We studied 48 patients: 22 with HCM (mean age: 22 +/- 5.1 years) and 26 age- and body surface area-matched healthy patients. They underwent a standard echocardiographic examination to assess left ventricular size and thickness. In addition, by integrated backscatter analysis, we assessed textural properties of left ventricular myocardium with calibrated averaged intensity (IB) and to assess functional properties of the myocardium with cyclic variation, both at the interventricular septum (IVS) and posterior wall. Finally, we studied ventricular late potentials (VLPs) by signal-averaged electrocardiography and performed a 24-hour electrocardiography Holter monitoring to respectively define electrical instability and ventricular arrhythmias.

RESULTS

Compared with control patients, patients with HCM had, both at IVS and posterior wall, increased IB (-28.8 +/- 10 vs -35 +/- 4 dB [P =.007] and -29 +/- 8 vs -33 +/- 5 dB [P <.035], respectively) and decreased cyclic variation (6.8 +/- 2.7 vs 10.3 +/- 2.3 dB [P <.001] and 8.2 +/- 2.9 vs 11.4 +/- 2.1 dB [P <.001], respectively). In all, 5 patients with HCM had positivity of VLPs, and 4 of them showed nonsustained ventricular tachycardia (nsVT) on the Holter monitoring. Compared with patients who had HCM without VLPs and nsVT, patients with positivity of VLPs and nsVT showed higher IB both at IVS (-15.8 +/- 8.4 vs -32.6 +/- 5.9 dB [P <.001] and -16.6 +/- 9.5 vs -31.5 +/- 7.5 dB [P =.002], respectively) and at posterior wall (-19.08 +/- 8.42 vs -32.5 +/- 4.2 dB [P <.001] and -22.4 +/- 4.6 vs -31 +/- 7.5 [P =.04], respectively). A multivariate analysis showed IB at IVS (P =.042; odds ratio = 1.19) and positivity of VLPs (P =.026; odds ratio = 3.67) as independent predictors of nsVT.

CONCLUSION

Patients with HCM showed abnormal morphologic and electrical properties of the myocardium. The correlation between VLPs and IB at IVS and their relationship with nsVT suggests a link between textural and electrical nonhomogeneity of myocardial fibers, a potential substrate of nsVT in patients with HCM.

Reflux nephropathy and hypertension: correlation with the progression of renal damage

The aim of this study was to evaluate the relationship between blood pressure (BP), measured with ambulatory blood pressure monitoring (ABPM), and the progression of renal damage in 100 (70 females, 30 males) normotensive children with reflux nephropathy (RN). The patients, mean age of 13.5+/-5 years and almost 5 years of follow-up, were divided according to degree of RN into group A (I/II) and group B (III/IV). For each subject, 24-h systolic and diastolic BP (SBP-DBP), load (percentage of BP readings that exceeded the age- and sex-specific 95th percentile), and biochemical parameters were recorded. There was no significant difference in casual BP between the groups. The mean 24-h SBP-DBP and load were significantly higher in group B than A. There was a significant difference in creatinine (Cr) levels between the groups, and Cr correlated with BP in both groups. In group B, microalbuminuria correlated with ambulatory BP, and plasma renin activity failed to decrease with chronological age. Elevated load was shown in 8 of 50 patients in group A and in 21 of 50 in group B. In 3 of 12 patients of group B, with increased load BP, left ventricular geometry, by integrated backscatter, was abnormal. ABPM was useful in selected children at risk of hypertension.

Do variable age-related secondary factors affect ventricular geometry in hypertrophic cardiomyopathy?

The relationship between cardiac shape and the age of patients with hypertrophic cardiomyopathy (HCM) has been established, and echocardiography has been accepted as the best method to quantitate ventricular cavity geometry. Recently, real-time three-dimensional volumetric data have demonstrated that children and young, middle-aged, and elderly patients with HCM have different morphologic and prognostic characteristics. This review discusses the importance of phenotypic expression and describes secondary factors that may affect ventricular cavity geometry during the progression of HCM.

Influence of propranolol infusion on cyclic variation of myocardial integrated backscatter in hypertrophic obstructive cardiomyopathy

It has been demonstrated that cyclic variation, assessed by myocardial integrated backscatter, reflects regional myocardial contractile function. The aim of this study was to investigate the influence of administration of beta-blocker propranolol on cyclic variation in patients with hypertrophic cardiomyopathy and persistent left ventricular (LV) pressure gradient and to test the hypothesis that the reduction of LV pressure gradient would be related to the change in regional contractile function. Before and after 2 mg propranolol infusion, transthoracic echocardiography with integrated backscatter analysis was performed on 11 patients (8 men and 3 women, mean age 54 +/- 12 years old). Integrated backscatter curves were obtained from the ventricular septum and LV posterior walls. With propranolol infusion, there was a significant reduction of LV fractional shortening (0.39 +/- 0.08 to 0.34 +/- 0.09, P <.01) and LV pressure gradient (83 +/- 40 mm Hg to 42 +/- 32 mm Hg, P <.001). In the posterior wall, the magnitude of cyclic variation significantly decreased (7.1 +/- 2.2 dB to 5.6 +/- 1.8 dB, P <.01), whereas in the septum, no apparent change in this parameter was observed (5.8 +/- 2.1 dB to 4.7 +/- 1.9 dB). Our findings suggest that in this form of cardiomyopathy, (1) the posterior wall myocardium is more susceptible to negative inotropic effects than the septum; (2) the reduction of LV pressure gradient is not related to that of regional wall motion; and (3) poor response of the ventricular septum is possibly because of more severe myocardial disarray and hypertrophy.

Enhanced method for predicting left ventricular reverse remodeling after surgical repair of aortic regurgitation: application of ultrasonic tissue characterization

To predict left ventricular (LV) reverse remodeling after surgical repair of aortic regurgitation, we examined 30 patients with aortic regurgitation accompanying LV dilatation by myocardial tissue characterization with integrated backscatter method. Before and after operation, the magnitude of cyclic variation of integrated backscatter (CVIB) was obtained from anterior septum and posterior wall, and averaged value was calculated in each patient. Before operation, LV end-diastolic dimension, fractional shortening, and LV end-diastolic pressure were not significantly different between the patients with (group GR) and without (group PR) decreased LV end-diastolic dimension after operation. Under these conditions, CVIB, which was 9.6 +/- 1.0 dB from healthy volunteers, was significantly greater in group GR, 5.7 +/- 1.4 dB, than that in group PR, 3.8 +/- 0.8 dB (P =.0003). The patients with CVIB >/= 4 before operation were expected to have reverse remodeling after operation with a sensitivity of 79%, a specificity of 82%. These data indicate that preoperative CVIB from the left ventricle provides pivotal information for predicting reverse remodeling after operation for aortic regurgitation in addition to the conventional echocardiographic parameters.

Dipyridamole stress ultrasonic myocardial tissue characterization in patients with Kawasaki disease

Dipyridamole stress integrated backscatter (IBS) was used for evaluation of myocardial ischemia or damage in 31 children with coronary artery lesions caused by Kawasaki disease, in comparison with thallium-201 myocardial imaging. All patients underwent echocardiography at rest and after dipyridamole stress at the anterior interventricular septum, posterior wall (PW), and inferior wall (INF). At rest, no significant difference was seen in cyclic variation (CV) of IBS in the regions with normal or abnormal distribution on Tl-201 imaging. But in the regions showing abnormal distribution after stress, CV decreased significantly. A delayed study after stress showed the recovery of CV to the level at rest in all patients. Sensitivity of abnormal cyclic variation integrated backscatter was 75% in the PW and 91% in the INF, and specificity was 91% in the PW and 90% in the INF, compared with the results of thallium-201 imaging. Dipyridamole stress IBS can provide sensitive detection of myocardial ischemia or damage in Kawasaki disease.

Myocardial integrated ultrasonic backscatter in patients with dilated cardiomyopathy: prediction of response to beta-blocker therapy

BACKGROUND

Myocardial integrated backscatter (IB) imaging has been reported to be useful for ultrasonic tissue characterization and delineation of myocardial viability or fibrosis. beta-Blocker therapy has beneficial effects for patients with dilated cardiomyopathy (DCM), but there are no clear findings that indicate which patients with DCM will respond to this therapy. This study was performed to evaluate whether myocardial IB analysis can predict the response to beta-blocker therapy.

METHODS AND RESULTS

We prospectively performed echocardiographic examination with IB analysis in 29 patients with DCM (20 men, 9 women) before starting bisoprolol therapy and in 15 normal subjects. Standard echocardiographic examination and IB analysis in the left ventricular wall in the 2-dimensional short-axis view were performed and the magnitude of cyclic variation (CV) of IB and calibrated myocardial IB intensity (subtracted pericardial) were obtained from the interventricular septum and the left ventricular posterior wall. Sixteen patients responded to bisoprolol therapy and 13 did not respond after 12 months of full-dose therapy. Calibrated myocardial IB intensity was lower in responders relative to nonresponders in both the interventricular septum (responders, -20.1 +/- 3.6 dB vs nonresponders, -9.8 +/- 5.1 dB, P <.0001; controls, -20.1 +/- 4.4 dB) and posterior wall (responders, -20.6 +/- 3.6 dB vs nonresponders, -14.6 +/- 4.2 dB, P =.0002; controls, -22.7 +/- 3.3 dB). Also, the lower the myocardial intensity in the interventricular septum or posterior wall, the better left ventricular systolic function improved after beta-blocker therapy. However, CV was lower in both DCM groups than in the controls, and CV in the interventricular septum was lower in nonresponders than in responders (responders, 4.0 +/- 4.1 dB vs nonresponders, -0.8 +/- 6. 1 dB, P <.02; controls, 8.3 +/- 2.4 dB). In addition, CV in the posterior wall showed no difference between the 2 DCM groups (responders, 5.6 +/- 1.3 dB vs nonresponders, 5.1 +/- 3.5 dB, P = not significant; controls, 9.6 +/- 2.5 dB). Also, the percent fibrosis on right ventricular endomyocardial biopsy specimens showed no distinctions between these 2 groups (responders, 25.1% +/- 16.1% vs nonresponders, 24.9% +/- 15.0%, P = not significant).

CONCLUSIONS

These findings suggest that left ventricular myocardial IB data, especially IB intensity, provide useful information for predicting the response to beta-blocker therapy in patients with DCM. However, right ventricular endomyocardial biopsy findings do not appear to contribute to discriminating between the 2 groups.