Diagnostic Clues for the Diagnosis of Nonsarcomeric Hypertrophic Cardiomyopathy (Phenocopies): Amyloidosis, Fabry Disease, and Mitochondrial Disease.

Hypertrophic cardiomyopathy (HCM) is the most common known inherited heart disorder, with a prevalence of 1:500 of the adult population. Etiology of HCM can be heterogeneous, with sarcomeric gene disease as the leading cause in up to 60% of the patients, and with a number of possible different diseases (phenocopies) in about 10%-15% of the patients. Early diagnosis of storage and infiltrative disorders, particularly those with specific treatments (i.e., Fabry disease and/or amyloidosis), means early management and treatment, with a significant impact on patients prognosis. Here, we report on four different cases of HCM, highlighting difficulties to make differential diagnosis of different forms of cardiomyopathies, and their potential impact on the management.

Impact of pulmonary regurgitation and age at surgical repair on textural and functional right ventricular myocardial properties in patients with tetralogy of Fallot.

BACKGROUND: The aim of this study was to identify non-invasively the potential impact of pulmonary regurgitation and age at surgical repair on the right ventricular (RV) textural and functional myocardial properties in patients operated on for tetralogy of Fallot (TOF). METHODS: We assessed the average intensity (Int.(1B)) and the cyclic variation (CV(IB)) of the echocardiographic backscatter curve in 30 TOF patients (mean age 16.2 +/- 8.3 years), who had undergone corrective surgery (mean age at repair 3.2 +/- 2.6 years, range 0.2-11 years). They were divided into three age- and body surface area (BSA)-matched subgroups according to the results of the surgical repair: 12 patients had no significant postsurgical sequelae (group I), 12 patients had isolated moderate-severe pulmonary regurgitation (group II), and 6 patients had pulmonary regurgitation associated with significant (> 30 mmHg) RV outflow tract obstruction (group III). In addition, 30 age-, sex- and BSA-matched normal subjects were identified as the control group. RESULTS: In our study population, CV(IB) was lower (7.86 +/- 2.5 vs 10.6 +/- 1.4 dB, p < 0.001) and Int.IB higher (-18.6 +/- 4.1 vs -21 +/- 2.8 dB, p = 0.01) compared to the control group. Comparison between the control group and each subgroup of TOF patients showed: a) comparable values of CV(IB) and Int.(IB) in group I (10.6 +/- 1.4 vs 9.4 +/- 2.3 dB, p = 0.07; and -21 +/- 2.8 vs -21.4 +/- 2.3 dB, p = 0.7, respectively); b) Int.(IB) was significantly different only in group III (-21 +/- 2.8 vs -13.3 +/- 4.6 dB, p < 0.0001), c) CV(IB) was different either in group II or III (10.6 +/- 1.4 vs 7.42 +/- 2, p < 0.001; and 10.6 +/- 1.4 vs 5.56 +/- 1.8, p < 0.001, respectively). In addition, comparison of integrated backscatter indexes among the TOF subgroups revealed significant differences of CV(IB) between group I and II (9.4 +/- 2.4 vs 7.4 +/- 2, p = 0.03) and between group I and III (9.4 +/- 2.4 vs 5.56 +/- 1.8, p = 0.004), and of Int.(IB) between group I and III (-21.4 +/- 2.3 vs -13.3 +/- 4.66, p < 0.001) and between group II and III (-21.4 +/- 2.3 vs -18.6 +/- 2.8, p = 0.006). Group III patients, who had the most significant RV dilation, expressed as the ratio between RV and left ventricular end-diastolic diameter (0.55 +/- 0.8) compared to group II (0.67 +/- 0.11, p = 0.038) and group I (0.55 +/- 0.87, p < 0.001), showed the lowest values of CV(IB) (5.56 +/- 1.8 dB) and the highest values of Int.(IB) (-13.3 +/- 4.6 dB) Finally, in our study population, both the degree of RV dilation and the age at surgical repair significantly correlated with Int.(IB) (r = 0.49 and r = 0.4, p = 0.06 and p = 0.033, respectively) and inversely correlated with CV(IB) (r = -0.55 and r = -0.53, p = 0.002 and p = 0.003, respectively). CONCLUSIONS: In patients operated on for TOF: a) integrated backscatter analysis may identify patients with significant RV myocardial abnormalities related to postsurgical sequelae; b) residual pulmonary regurgitation, particularly if associated with pulmonary stenosis, appears to affect RV myocardial properties; c) an earlier repair of TOF may result in better preservation of myocardial characteristics.

Backscatter evaluation of myocardial functional and textural findings in children with right ventricular pressure and/or volume overload.

Integrated backscatter (IBS) analysis represents a recent echocardiographic technique for evaluating the textural and functional state of the right ventricular (RV) myocardium. We undertook our study to (1) define the potential impact of age or morphometric parameters (height, weight, and body surface area) on RV IBS indexes, and (2) compare RV IBS data among normal subjects and children with different conditions of RV overload. We studied 34 patients (mean age 14.6 +/- 4.7 years) divided into 3 groups: 14 patients with RV volume overload related to moderate to large atrial septal defect (group I); (2) 10 patients with RV pressure overload due to transposition of the great arteries after the Mustard procedure (group II); and (3) 10 patients with RV volume and pressure overload due to pulmonary regurgitation and stenosis after corrective surgery for tetralogy of Fallot (group III). In addition, 20 children with structurally normal hearts were enrolled as the control group. The 4 groups were comparable with regard to age and morphometric parameters. IBS parameters were assessed as the magnitude of cyclic variation, determined as the difference between peak and nadir IBS values and the averaged myocardial IBS intensity. In the control group and group I, IBS parameters did not change significantly with age, height, weight, and body surface area. In contrast, in groups II and III, a significant correlation was found between cyclic variation and age at the study (p = 0.021, r = -0.71, and p = 0.006, r = -0.79, respectively). Furthermore, compared with the control group, cyclic variation and IBS intensity were significantly different only in groups II (p = 0.01 and p = 0.006, respectively) and III (both p <0.0001) but not in group I (p = 0.23 and p = 0.38, respectively). The lowest values of cyclic variation and the highest values of intensity were detected in group III patients. Thus, our data suggest that (1) in normal subjects, there is no correlation between RV IBS indexes and age or any morphometric parameters, and (2) IBS analysis is able to noninvasively detect differences in myocardial functional and textural properties in the presence of different conditions of RV overload.