The potential impact of hereditary hemochromatosis on the heart considering the disease stage and patient age-the role of echocardiography.

Background: Hereditary hemochromatosis (HH) is a genetic disease that leads to increased iron accumulation in several organs. Cardiomyocytes are highly susceptible to this damage owing to their high iron uptake, and cardiovascular complications account for 1/3 of the deaths in the natural course of HH. Additionally, excess iron intake and associated oxidative stress may accelerate the aging of the cardiovascular system, regardless of the age of patients with HH. We aimed to investigate the role of standard and speckle-tracking echocardiography (STE) in revealing heart differences in patients with HH considering the disease stage and the patient age. Methodology: Consecutive patients with HH (n = 58) without heart pathologies (except hypertension) and 29 age- and sex-matched healthy individuals underwent echocardiography. Patients were compared according to the time since HH diagnosis (the recently diagnosed HH group [31 patients] with diagnosed HH for less than 6 months and had no more than one venesection; the medium group [11 patients] with diagnosed HH between 6 and 24 months; and the long-lasting group [16 patients] with diagnosed HH for more than 2 years) and the quartile contribution of their age. Results: Standard echocardiography revealed differences in diastolic parameters between patients with HH and controls, which were the most prominent between healthy and long-lasting HH patients. Regarding systolic function, left ventricular ejection fraction was lower in HH patients, with the most evident differences between the healthy and recently diagnosed HH patients. STE revealed additional differences in systolic parameters, with LV rotation the worst in recently diagnosed patients and its increase in patients with medium and long-lasting HH. Significantly worse peak systolic longitudinal strain values were observed in all patients with HH. Analyses of the results according to the age quartiles of patients with HH revealed that some changes ocurred earlier than expected according to age. Conclusions: Echocardiography can reveal possible heart damage in HH patients at different stages of the disease and highlight potential features of accelerated myocardial aging in these patients.

Left Ventricular Function and Iron Loading Status in a Tertiary Center Hemochromatosis Cohort-A Cardiac Magnetic Resonance Study.

Background: Haemochromatosis (HCH), a common genetic disorder with variable penetrance, results in progressive but understudied iron overload. We prospectively evaluated organ iron loading and cardiac function in a tertiary center HCH cohort. Methods: 42 HCH patients (47 ± 14 years) and 36 controls underwent laboratory workup and cardiac magnetic resonance (CMR), including T1 and T2* mapping. Results: Myocardial T2* (myoT2*), myocardial T1 (myoT1) and liver T2* (livT2*) were lower in patients compared to controls (33 ± 4 ms vs. 36 ± 3 ms [p = 0.004], 964 ± 33 ms vs. 979 ± 25 ms [p = 0.028] and 21 ± 10 ms vs. 30 ± 5 ms [p < 0.001], respectively). MyoT2* did not reach the threshold of clinically significant iron overload (<20 ms), in any of the patients. In 22 (52.4%) patients, at least one of the tissue parameters was reduced. Reduced myocardial T2* and/or T1 were found in 10 (23.8%) patients, including 4 pts with normal livT2*. LivT2* was reduced in 18 (42.9%) patients. MyoT1 and livT2* inversely correlated with ferritin (rs = −0.351 [p = 0.028] and rs = −0.602 [p < 0.001], respectively). LivT2* by a dedicated sequence and livT2* by cardiac T2* mapping showed good agreement (ICC = 0.876 p < 0.001). Conclusions: In contemporary hemochromatosis, significant myocardial iron overload is rare. Low myocardial T2* and/or T1 values may warrant closer follow-up for accelerated myocardial iron overload even in patients without overt liver overload. Cardiac T2* mapping sequence allows for liver screening at the time of CMR.

Can two-dimensional speckle tracking echocardiography be useful for left ventricular assessment in the early stages of hereditary haemochromatosis?

BACKGROUND: Hereditary haemochromatosis (HH) is a common inherited disease. Abnormally increased intestinal iron absorption and accelerated recycling of iron by macrophages lead to progressive body iron accumulation and the generation of oxidative stress. In the late stages, iron overload can lead to dysfunction of the left ventricle (LV). It is believed that two-dimensional speckle tracking echocardiography (2D STE) can evaluate LV dysfunction more accurately than conventional echocardiography. This accurate evaluation seems to be clinically important in the early stages of HH before substantial damage of the LV. Evaluation of this assessment was the purpose of this paper. METHODS: We prospectively enrolled 24 patients with early diagnosed HH and without any history of cardiovascular diseases; 23 healthy age- and sex-matched volunteers constituted the control group. Standard echocardiographic parameters and LV rotation and strain parameters were assessed and compared between the groups. RESULTS: All echocardiographic parameters were within normal ranges, and there were no differences between the groups. 2D STE revealed significantly worse basal and apical rotation, twist and torsion values in HH patients. The peak systolic longitudinal strain was decreased in HH patients, even though the LV ejection fraction (LVEF) was normal. There were weak correlations between the iron turnover and 2D STE parameters. CONCLUSIONS: 2D STE seems to be more sensitive than traditional echocardiography for detecting LV abnormalities in HH patients who are diagnosed early. The results of this study may be clinically useful, but their relevance and therapeutic implications remain to be confirmed by further studies.

Microvolt T-wave alternans and autonomic nervous system parameters can be helpful in the identification of low-arrhythmic risk patients with ischemic left ventricular systolic dysfunction.

INTRODUCTION: The role of implantable cardioverter-defibrillator (ICD) placement in the primary prevention of sudden cardiac death (SCD) in all consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35% is still a matter of hot debate due to the fact that the population of these patients is highly heterogeneous in terms of the SCD risk. Nevertheless, reduced LVEF is still the only established criterion during qualification of patients for ICD implantation in the primary prevention of SCD, therefore identification of persons with particularly high risk among patients with LVEF ≤35% is currently of lesser importance. More important seems to be the selection of individuals with relatively low risk of SCD in whom ICD implantation can be safely postponed. The aim of the study was to determine whether well-known, non-invasive parameters, such as microvolt T-wave alternans (MTWA), baroreflex sensitivity (BRS) and short-term heart rate variability (HRV), can be helpful in the identification of low-arrhythmic risk patients with ischemic left ventricular systolic dysfunction. METHODS: In 141 patients with coronary artery disease and LVEF ≤ 35%, MTWA testing, as well as BRS and short-term HRV parameters, were analysed. During 34 ± 13 months of follow-up 37 patients had arrhythmic episode (EVENT): SCD, non-fatal sustained ventricular arrhythmia (ventricular tachycardia [VT] or ventricular fibrillation [VF]), or adequate high-voltage ICD intervention (shock) due to a rapid ventricular arrhythmia ≥200/min. LVEF, non-negative MTWA (MTWA_non-neg), BRS and low frequency power in normalized units (LFnu) turned out to be associated with the incidence of EVENT in univariate Cox analysis. The cut-off values for BRS and LFnu that most accurately distinguished between patients with and without EVENT were 3 ms/mmHg and 23, respectively. The only variable that provided 100% negative predictive value (NPV) for EVENT was negative MTWA result (MTWA_neg), but solely for initial 12 months of the follow-up; the NPVs for other potential predictors of the EVENT were lower. The cut-off values for BRS and LFnu that provide 100% NPV for EVENT during 12 and 24 months were higher: 6.0 ms/mmHg and 73 respectively, but the gain in the NPV occurred at an expense of the number of identified patients. However, the number of identified non-risk patients turned out to be higher when the predictive model included MTWA_neg and the lower cut-off values for ANS parameters: 100% NPV for 12 and 24 months of follow-up was obtained for combination MTWA_neg and BRS ≥ 3 ms/mmHg, for combination MTWA_neg and LFnu ≥ 23 100% NPV was obtained for 12 months. CONCLUSION: Well-known, non-invasive parameters, such as MTWA, BRS and short-term HRV indices may be helpful in the identification of individuals with a relatively low risk of malignant ventricular arrhythmias among patients with ischemic left ventricular systolic dysfunction; in such persons, implantation of ICD could be safely postponed.

Microvolt T-wave alternans profiles in patients with pulmonary arterial hypertension compared to patients with left ventricular systolic dysfunction and a group of healthy volunteers.

OBJECTIVE: Microvolt T-wave alternans (MTWA) is a well-examined parameter for the risk stratification of sudden cardiac death (SCD) in patients with left ventricular dysfunction (LVD). However, the role of MTWA in pulmonary arterial hypertension (PAH) remains obscure. Consequently, the present study aimed to analyze the profile of MTWA among PAH patients in comparison with LVD patients and healthy volunteers. METHODS: The prospectively study included 22 patients with PAH (mean pulmonary artery pressure ≥ 25 mm Hg and pulmonary capillary wedge pressure ≤15 mm Hg during right heart catheterization; mean age, 40±17 years); 24 with LVD [left ventricular ejection fraction (LVEF) ≤35%; mean age, 40±11 years]; and 28 healthy volunteers (mean age, 41±8 years). Patients with persistent atrial arrhythmia were excluded. The MTWA (spectral method) categories were positive, negative, or indeterminate (MTWA_pos, MTWA_neg, or MTWA_ind, respectively). MTWA_pos and MTWA_ind were qualified as abnormal (MTWA_abn). Statistical analyses (Mann-Whitney U, chi-square with Yates's correction, Fisher's exact test) were performed. RESULTS: PAH patients had higher LVEF than LVD patients (61±7% vs. 27±7%; p<0.05). MTWA_abn was observed more frequently in the PAH and LVD groups than in the healthy volunteers. Patients with PAH were characterized by a considerable percentage of MTWA_pos and MTWA_abn (59% and 73%, respectively), but this did not differ from LVD patients. CONCLUSION: Patients with PAH are characterized by a high rate of MTWA abnormalities similar to LVD patients, despite the relevant differences in LVEF. Further research is required to elucidate the clinical significance and prognostic value of this data, particularly in the context of SCDunderlying mechanisms in PAH patients.

Autonomic Predictors of Hospitalization Due to Heart Failure Decompensation in Patients with Left Ventricular Systolic Dysfunction.

INTRODUCTION: Autonomic nervous system balance can be significantly deteriorated during heart failure exacerbation. However, it is still unknown whether these changes are only the consequence of heart failure decompensation or can also predict development thereof. Objectives were to verify if simple, non-invasive autonomic parameters, such as baroreflex sensitivity and short-term heart rate variability can provide independent of other well-known clinical parameters information on the risk of heart failure decompensation in patients with left ventricular systolic dysfunction. METHODS: In 142 stable patients with left ventricular ejection fraction ≤ 40%, baroreflex sensitivity and short-term heart rate variability, as well as other well-known clinical parameters, were analyzed. During 23 ± 9 months of follow-up 19 patients were hospitalized due to the heart failure decompensation (EVENT). RESULTS: Pre-specified cut-off values of baroreflex sensitivity (≤2.4 ms/mmHg) and low frequency power index of heart rate variability (≤19 ms2) were significantly associated with the EVENTs (hazard ratio 4.43, 95% confidence interval [CI] 1.35-14.54 and 5.41, 95% CI 1.87-15.65 respectively). EVENTs were also associated with other parameters, such as left ventricular ejection fraction, NYHA class, diuretic use, renal function, brain natriuretic peptide and hemoglobin level, left atrial size, left and right ventricular heart failure signs. After adjusting baroreflex sensitivity and low frequency power index for each of the abovementioned parameters, autonomic parameters were still significant predictors of hospitalization due to the heart failure decompensation. CONCLUSION: Simple, noninvasive autonomic indices can be helpful in identifying individuals with increased risk of hospitalization due to the heart failure decompensation among clinically stable patients with left ventricular systolic dysfunction, even when adjusted for other well-known clinical parameters.