Assessment of left ventricular and atrial diastolic function using two-dimensional (2D) strain imaging in patients with ß-thalassemia major.

BACKGROUND: ß-thalassemia major is a unique disease characterized by early severe diastolic dysfunction, due to iron myocardial deposition alone, while left ventricular systolic dysfunction and failure seem to be multifactorial in aitiology. OBJECTIVES: The purpose of this study was to investigate left ventricular diastolic dysfunction using a new echo index as speckle tracking in comparison with the conventional methods. MATERIAL AND METHODS: Eighty-eight consecutive patients (38 male, 50 female) aged 36 ± 8.2 yr with ß-thalassemia major and preserved LV ejection fraction (LVEF>55%) were studied. Patients were divided into two groups according to the E mitral/E mitral annulus ratio (E/E'): group A patients with E/E' ratio ≤8 and group B patients with E/E' >8. Cutoff value of eight was used to separate patients with normal and abnormal diastolic function. All subjects were studied thoroughly by tissue Doppler echocardiography as also by 2D left ventricular and atrial strain imaging 2-4 d following blood transfusion. Blood samples were also taken for plasma BNP measurements at the same time. RESULTS: Left atrial volumes(LAV max, LAV min) as also left atrial index were significantly higher in patients with diastolic dysfunction compared with patients without diastolic dysfunction(LAV max: 57.6 ± 19.4 vs. 71.3 ± 22.9, P < 0.01,LAV min: 20.2 ± 11.4 vs. 33.9 ± 18, P < 0.01, LAVI: 37.66 ± 12.18 vs. 47.13 ± 14.77, P < 0.01). Radial 2D strain (RS) and peak atrial 2D strain (AS) were significantly reduced in patients with suspected diastolic dysfunction compared with patients without diastolic dysfunction (RS: 43.48 ± 13.92 vs. 35.58 ± 11.32, P < 0.05; AS: 36.36 ± 8.45 vs. 29.85 ± 9.25, P < 0.01). Using ROC analysis, peak atrial 2D strain at a cutoff of 41.1 cm/s was highly accurate (AUC: 0.66, P < 0.05 in ruling out diastolic dysfunction (E/E'<8) with a sensitivity of 90% and a specificity of 81%. CONCLUSIONS: B-thalassemic major patients with preserved left ventricular systolic function had impaired left atrial function at the longitudinal axis and left ventricular function at the radial axis. The new echo markers have better prognostic value than the traditional echo indexes in detecting latent diastolic dysfunction in ß-thalassemia major, earlier than E/E' ratio.

An amyloidogenic determinant in N-terminal pro-brain natriuretic peptide (NT-proBNP): Implications for cardiac amyloidoses.

Deposition of amyloid in the atria (isolated atrial/cardiac amyloid) is fairly common in the aging heart. It consists of amyloid fibrils, formed both by atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) and the precursor molecule of ANP, proANP. This study examines whether amyloidogenic determinants (short peptides/amyloid forming favoring regions) exist in the sequence of NT-proBNP, the N-terminal part of proBNP, and if these determinants form amyloid-like fibrils in vitro. We have predicted a possible amyloidogenic determinant in the sequence of the NT-proBNP, and we conclusively show, after its synthesis, that it forms amyloid-like fibrils in vitro, utilizing transmission electron microscopy, X-ray diffraction, attenuated total reflectance Fourier-transform infrared spectroscopy, and polarizing microscopy. Thus, for the first time, in this study, a possible biological role is attributed to a certain, specific part of this important cardiac prohormone/natriuretic peptide, which acts as an important biomarker indicative of heart failure. Its possible direct involvement in isolated cardiac amyloidosis, atrial fibrillation, and other types of cardiac amyloidoses is indicated and discussed. Since these cardiac hormones and their prohormones play key roles in cardiovascular homeostasis through natriuresis, diuresis, vasorelaxation, and inhibition of renin and aldosterone secretion (pathophysiology of hypertension and cardiovascular regulation), we also try to suggest these specific, short peptides as possible future structural targets of efforts toward inhibiting formation of natriuretic peptide(s) amyloid.

NT-proBNP levels and diastolic dysfunction in beta-thalassaemia major patients.

BACKGROUND: The early diagnosis and treatment of heart failure in beta-thalassaemic patients is related to survival. Iron alone or in combination with other factors causes diastolic dysfunction, which usually precedes systolic dysfunction. NT-proBNP is a sensitive biomarker of ventricular dysfunction. AIM: To evaluate NT-proBNP in non heart failure beta-thalassaemic patients. METHODS: Fifty-two beta-thalassaemia major patients (mean age: 27.2+/-12.5 years) with normal LV systolic function, underwent NT-proBNP measurement and a thorough Doppler-echocardiographic and pulsed tissue-Doppler study, 4 days following blood transfusion. Fifty-two age matched healthy controls were also studied. RESULTS: NT-proBNP and E/E' ratio were increased in thalassaemic patients compared with controls [(469+/-171 vs 262+/-51 pmol/l, p<0.001) and (10.8+/-4.0 vs 6.6+/-1.1, p<0.001)] and were well correlated (r: 0.54, p<0.01). Although NT-proBNP levels were increased in patients with higher E/E' ratios (E/E' <8: 354+/-119, 8-15: 516+/-177, >15: 565+/-114 pmol/l, ANOVA p: 0.002) this increase only became statistically significant in the 3rd decade of life, while E/E' ratio increased in the 4th decade. CONCLUSION: NT-proBNP increases in beta-thalassaemia major patients and is related to age and LV diastolic dysfunction. NT-proBNP appears to be an early biomarker of LV diastolic dysfunction, compared with the conventional Echo-Doppler indexes.

Management of inadvertent left ventricular permanent pacing.

Inadvertent implantation of a pacemaker lead in the left ventricle is an uncommon complication. We report a case of a permanent pacemaker lead inadvertently placed through the left subclavian artery, across the aortic valve into the left ventricle. A chest X-ray one month after the procedure showed an unusual course of the lead and a 12-lead ECG and a transthoracic echocardiogram confirmed the diagnosis. The patient refused surgical removal and remained on full anticoagulation. No clinical events were recorded during a 3-year follow-up. In such cases we propose life-long full anticoagulation as an alternative to surgical lead extraction.