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br Materials and methods br Results The two groups
Materials and methods
Results
The two groups were similar regarding age, sex, systolic blood pressure, diastolic blood pressure, and heart rate (bpm) (Table 1). LV end-diastolic dimension, LV end-systolic dimension, posterior wall thickness, and LV ejection fraction (%) were not statistically different between the groups (Table 2). Left atrial dimension and interventricular septal thickness were higher and deceleration time was lower in patients who underwent heart transplantation than in the control population (Table 2). Biochemical and complete blood count parameters were not statistically different between the groups. Two-dimensional conventional Doppler and the PA parameters of different sites measured by DTI are shown in Table 2. PA lateral (68±7 vs. 51±11ms, p<0.01), PA septal (50±5 vs. 42±8ms, p<0.01) and PA tricuspid (39±6 vs. 36±9ms, p<0.01) values were higher in patients who underwent heart transplantation than in a control population (Table 2). Furthermore, inter-AEMD, right AEMD and left intra-AEMD were prolonged in patients who underwent heart transplantation as compared to the control population. Inter-AEMD (27±7 vs. 10±4ms, p<0.01), left intra-AEMD (18±7 vs. 10±4ms, p<0.01), right intra-AEMD (13±5 vs. 5±3ms, p<0.01) (Fig. 2).
Discussion
Prolongation of intra-AEMD and inter-AEMD and the inhomogeneous propagation of sinus impulses are well-known electrophysiologic characteristics of the atria prone to fibrillation [5–7,17–24]. Fibrosis in the left atrium and left ventricle accounts for the development of LV diastolic dysfunction and AF [24–37]. Increases in intra- and inter-AEMD have been identified in patients who are prone to develop AF, such as those with mitral stenosis, familial Mediterranean fever, type II diabetes, scleroderma, paroxysmal AF, and essential hypertension [5–7,20,21]. The anisotropy and dispersion of refractory periods resulting from the decrease in electrical connections and deposition of geldanamycin between the myocytes may lead to atrial conduction abnormalities, resulting in intra- and inter-AEMD that can prepare a convenient substrate for AF [38–40]. However, because the number of wavelets at any time depends on the refractory period, mass, and conduction velocity in different parts of the atria, the shortened refractory period and delayed conduction may increase the quantity of daughter wavelets according to the multiple wavelet hypothesis.
Deniz et al. determined the correlation of AEMD with the electrophysiologic (EPS) and DTI measurements, and evaluated the appropriateness of the usage of DTI in patients with clinical arrhythmias [41]. However, Erdem et al. validated the correlation of AEMD with TDI and EPS measurements in healthy subjects. They suggested that DTI measurements of AEMD may be used accurately and confidently instead of the EPS and were significantly advantageous because of their low cost and non-invasiveness [42].
To our knowledge, there is no prior study of AEMD in patients undergoing heart transplantation. In this study, we found that intra- and inter-AEMD were higher in patients who underwent heart transplantation than in a control population. All patients included our study were operated on by using the orthotopic biatrial technique. In this technique, the incision that originates from the inferior vena cava is extended to the right atrial appendix. Then, the incision is lengthened to the left atrial ceiling in the vicinity of the transverse sinus. The septal suture line is revealed by extending the right atrial incision line towards the septum and septal leaflet of the tricuspid valve, and is connected to the incision in the left atrial wall. In the bicaval technique, the heart is extracted relatively intact and much fewer incisions are applied to the atrial tissue. Extensive incision lines applied to atrial tissue may create electrophysiological instability by disturbing action potential propagation velocity and homogeneous distribution, thus creating a tendency to AF after using the biatrial technique. Owing to more extensive surgery lines, a temporary pacemaker requirement, left bundle branch block, and atrioventricular block were also observed statistically more significantly often compared to bicaval anastomosis [43–46]. In a study comparing the atrial arrhythmia incidence after both techniques, 31 bicaval and 35 biatrial operated patients were examined and the AF incidence were found to be significantly higher in the biatrial group (21 vs. 3 patients, p<0.01) [47]. Therefore, it can be suggested that bicaval anastomosis may be a better choice for avoiding future arrhythmias in patients undergoing heart transplantation.