Atrial and ventricular function in thalassemic patients with supra-ventricular arrhythmias

Abstract

The aims of this study were to evaluate through Color Doppler Myocardial Imaging (CDMI) echocardiography if atrial or ventricular myocardial alterations could be detectable in patients with thalassemia major (THAL) and if these alterations could be considered as predictive elements for supra-ventricular arrhythmic events. Twenty-three patients with THAL underwent clinical and electrocardiographic evaluation; patients were grouped in THAL1 (9 with supra-ventricular arrhythmias) and THAL2 (14 without arrhythmias); 12 healthy subjects were considered as control group (C). We examined through conventional 2D Color Doppler echocardiography some morphological and functional parameters regarding left ventricular (LV) systolic and diastolic function, and through CDMI the velocities at mitral annulus level, the regional LV and left atrial (LA) strain and strain rate. All THAL patients had LV dimension (p<0.05), LA area (p<0.01) and E/Em ratio (p<0.001) to be significantly higher than controls. The mitral annulus longitudinal velocities were significantly lower in THAL1 than in THAL2 (p<0.001); the E/Em ratio was higher in THAL1 than THAL2 (p<0.001). The THAL1 showed a lower systolic strain rate of atrial wall than THAL2 and C (p<0.05). The multiple regression highlighted a significantly inverse correlation among E/Em and atrial strain (p<0.02). CDMI showed both THAL subgroups had subtle systolic and diastolic left ventricular myocardial alterations, which could represent the onset of developing "iron cardiomyopathy" and are related to supra-ventricular arrhythmia. Monitoring these parameters in the THAL patients could contribute to decisions about follow-up and therapy.

Keywords: echocardiography; myocardial dysfunction.; thalassemia.

Figure 1

Color doppler myocardial imaging: apical 4 chamber views of interested areas at basal segments of interventricular septum and lateral wall, at distal segments of the interatrial septum and atrial lateral wall. In graphics the traces of strain rate at selected points.

Figure 2

Correlation between the ratio of early transmitral flow velocity/early diastolic velocity at mitral septal annulus (E/Em, x axis) and the left ventricular wall strain rate at peak E (LVW SR-E, y axis) in all the Thalassemic population. A statistically significant relation is observed.

Figure 3

Left panel: correlation between the ratio of early transmitral flow velocity/early diastolic velocity at mitral septal annulus (E/Em, x axis) and the left atrial wall strain rate at peak E (LAW SR-E, y axis) in all the Thalassemic population. Right panel: correlation between the ratio of early transmitral flow velocity/early diastolic velocity at mitral lateral annulus (E/Em, x axis) and the left atrial wall strain rate at peak S (LAW SR-S, y axis) in all the Thalassemic population. A statistically significant relation is observed.