CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 2, May/June 2023 112 AFRICA volume is the hallmark change seen in athletes training for endurance.21 The findings of this study are consistent with the abovementioned findings reported in the literature. Individuals who undergo physical training do not exhibit a uniform response to systematic conditioning. On the other hand, the most common form of cardiac remodelling observed in athletes is the increased diameters of the LV, right ventricular (RV) and LA cavities with normal systolic and diastolic function.20 The findings of this study revealed similar cardiac remodelling in athletes. LA remodelling is generally believed to be an adjunctive physiological adaptation mechanism, most commonly seen in rowers or cyclists.20 Several authors have questioned the importance of LA enlargement as a preclinical abnormality,17 suggesting that these changes represented an innocent consequence of regular and intensive training. Nemes et al.4 demonstrated the increase in cyclic LA volumes and LA stroke volumes in young competing athletes without LV hypertrophy. They concluded that LA enlargement is likely a physiological outcome of global cardiac adaptation in response to intensive and chronic training. Gjerdalen et al.1 demonstrated significant variations in the diameters of both the left and right atria and a disproportional enlargement of the atria in comparison with the corresponding ventricles in football players compared to control subjects. Hence, the changes in the LA should be investigated as a single variable to understand its role in individuals who are actively engaged in physical training. An increased cardiac dimension is essential for athletes to perform a large stroke volume.20,22 The morphological changes in LA diameters, such as LA enlargement, observed in athletes have been investigated previously.1,3,11,12,21 Pelliccia17 reported that LA enlargement was observed in 20% of the 1 777 athletes included in the study. In addition to LA enlargement, they also speculated that the amount of maximum LA volume was directly related to LV mass index. In parallel, they concluded that LV enlargement and volume overload are the primary driving factors for the volumetric changes observed in the LA.11,17,20 D’Ascenzi et al.9 reported similar findings in adolescent elite football players. Although the degree of LV hypertrophy is related to the type, intensity and volume of the physical conditioning, the impact of football on the LV cavity size is more prominent than the LV wall thickness in elite football players.20,21 However, no significant difference was found between the football players and the control subjects included in this study in terms of LV mass. Others have speculated that higher vagal tone due to the increased LA filling pressure might be the reason for LA enlargement.13,23 Complex relationships exist between the heart’s different anatomical and functional parts, including the LV and LA. Hence, further studies are needed to clarify the controversy on the pathophysiology of LA remodelling. Several authors have compared the degree of LA enlargement in athletes.1 However, it is difficult to compare the results of these studies since they feature different recording conditions, calculation methods, and disproportionate numbers of highstatic/low-dynamic athletes. In one of these studies, Kartal et al. found that football players had larger indexed LA volumes during the times of atrial systole and passive emptying, but that their volumes were comparable during the times of maximal atrial filling. In football players, the LA volume increases during the pumping phase. In our study, maximum and minimal LA volumes (also indexed volumes) were greater in football players.24 Tumuklu et al.5 determined significant increases in LA diameter in football players. In another study, Cameli et al.11 demonstrated that active training led to the larger indexed LA volumes during both active atrial filling and passive emptying in top-level athletes. They also found a positive correlation between the intensity and volume of the physical training and the changes in LA volume. Interestingly, the changes in LA volume were reportedly reversible. As a matter of fact, considerable reductions were recorded in LA volume after two months without training, comparable to the levels recorded in the pre-training period.11 In our findings, although PVAT [a surrogate of pulmonary artery systolic pressure (PASP)] measurements were higher in football players, the PASP of both groups was estimated to be normal according to PVAT results (> 130 ms). There was also no difference in estimated PASP, which was also within the normal range. Although the TAPSE measurement was statistically higher in the football players’ group, the TAPSE was normal in both groups, indicating normal right heart systolic function. In 2D echocardiography, complete evaluation of the right heart is not possible. Although right ventricular ejection fraction (RVEF) was visually assessed by the researcher, TAPSE measurement is accepted as a more accurate and valid measurement than RVEF. Abnormal ECG patterns are usually seen in athletes that participate in endurance sport.20 Although early repolarisation, increased QRS voltage, diffuse T-wave inversion, and deep Q waves are the most commonly encountered abnormalities, the P wave and its morphology has gained significant attention in recent years.25,26 There are controversial findings on P-wave abnormalities in athletes. Herrera et al.25 found no significant change in electrocardiographic parameters, including P-wave morphology. Others also did not find any significant change in the respective electrocardiographic parameters of young, healthy athletes.26 Similarly, no significant difference was found in P-wave morphology between the groups investigated within the scope of this study. Although the groups significantly differed in terms of P-wave duration, the direct consequences of LA changes on the electrophysiological parameters could not be proven. PR interval was longer in the football player group but within the normal range in both groups. Although the heart rate was slightly higher in the football player group (sinus node was more sensitive to sympathetic activity), the longer PR interval may be due to the predominance of parasympathetic tone in athletes and the decremental conduction property of the atrioventricular node.27 In addition, it is observed that the patient group consisted of football players playing in the amateur league, and as the difficulty level of the football league increased, vagal tonus increased and heart rate decreased further.28 There are some limitations to the study. The relatively small sample size and selection of the study participants without using any random sampling method may be deemed as two of the limitations. Additionally, the differences between the intensity and volume of the physical training of each participant might have confounded the study results. The age-dependent increase in LA size has been reported in the literature.13 However, age may act as a dummy variable given the homogeneity of the study groups studied in similar studies.13 The sample size also acted
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