an increasing number of medical specialties such as dermatology ,   oncology , radiology , surgery , cardiology , and psychiatry use telemedicine routinely.in a country like greece , which consists of several small islands dispersed around a mountainous mainland with many remote parts , telemedicine is not only beneficial but rather necessary for high - quality healthcare provision to its population.the services of telemedicine in their modern form appeared in greece in 1991 . due to the low reliability of the plain old telephone service ( pots ) at the beginning of these efforts ,
the implementations became wireless , via satellite links .however , the digitization of the pots and the general improvement of the telecommunication infrastructure , especially the deployment of gsm ( global system for mobile communications ) networks , which took place since then , have favoured further developments in the field [ 35 ] .
telecardiology and specifically transtelephonic electrocardiographic transmission ( tet ) remains the most widespread form of telemedicine since it can ensure a valid , reliable , and objective assessment of cardiac 
 rhythm and function.however , its use in sports medicine is not so widely mentioned , 
 and relevant studies are very scarce in the international literature . 

perhaps the only known application in this area is the follow - up of patients with cardiovascular disease during their rehabilitation exercise [ 610 ] . with the increasing number of individuals having physically active lifestyles ,
transient risk of cardiovascular events during exercise is not rare , especially among athletes with unrecognized 
 cardiovascular diseases.therefore , at least annual preparticipation screening is generally recommended prior to participation in sports.in order to increase the number of athletes properly tested , the screening program should be accurate , practical to apply under field conditions to large numbers of 
 subjects , and have relatively low cost .
the purpose of the study was to evaluate whether it 
 was technically feasible and effective for a general practitioner ( gp ) to 
 examine amateur soccer players in their playfields and transmit , when this was 
 judged necessary , a 12-lead ecg and a clinical record to a sports medicine base 
 for further evaluation by a cardiologist . 

a secondary purpose was to determine whether the data could be reliably 
 transmitted via the cellular communication system , as an alternative in the 
 absence of a fixed telephone line .
ten percent of the active soccer clubs of the prefecture of thessaloniki , 
 in northern greece , participated in this study . specifically , from the total of 230 soccer clubs , 
 23 of urban and rural areas were randomly selected .
the study population 
 included 506 young soccer players , who were asked to fill in a questionnaire so 
 that information about the medical record of the athlete and his family could 
 be collected.additionally , anthropometric and clinical data were recorded , 
 that is , height , weight , systolic and diastolic blood pressure , and resting heart rate .
all athletes underwent physical examination , including precordial auscultation in both the supine and 
 standing positions .
murmurs were further evaluated with the valsalva 
 maneuver.additionally , resting 12-lead ecg was performed in all subjects . in the case of unusual findings , as judged by the gp , from the medical history , physical examination and/or ecg , the 
 latter together with a clinical record were transmitted from the examination 
 site to the laboratory of sports medicine for further evaluation by a 
 cardiologist . the device used for storing and transmitting the ecg was a portable electrocardiograph ( cardiette excel 
 106scp ) with an internal modem and a capability of connecting to an external 
 one with a transmission speed of up to 19.2  kbps.an important feature of the electrocardiograph was the compression of data before transmission , which allowed high quality 12-lead recordings to be sent in small files . in the absence of a fixed telephone line ( pots ) , a dual - band gsm ( 900/1800  mhz ) modem was used ( siemens tc35 terminal ) working with the circuit switched data ( csd ) bearer service of a 
 national operator with more than 99% geographical coverage and a nontransparent 
 data rate of 9.6  kbps.the data calls from the electrocardiograph were terminated at a workstation running the software package medibox cardiobox of h&c medical devices s.p.a . and 
 connected with a modem to the pots.the communication between the cardiologist sitting in front of this workstation and the medical team in the field for reporting was always carried out with a 
 mobile phone.following the initial assessment , 58 athletes were given further appointments for echocardiography , stress test , and 24-hour holter monitoring of ecg or blood pressure .
descriptive statistics were used to describe categorical variables.for statistical 
 analysis , the statistics toolbox of matlab was used ( the mathworks inc . , ma , usa ) .
the correlation coefficient was derived to assess the association between the reception level of gsm and the number of 
 failed transmissions .
the locations where the preparticipation screening took place were at a distance between 
 4 and 82.2  km 
 ( 19.35  18.22 km ) from the 
 specialised examination centre at the laboratory of sports medicine , which is situated at the center of the city of thessaloniki .
the mean transportation time of the healthcare team ( one gp and one nurse ) from the city centre to the locations of the athletes was 23.26 minutes ( sd 17.73 ) .
most of the soccer clubs ( n = 16 or 69.6% ) had their 
 own sports facilities , where the athletes were examined .
however , only a small number 
 ( n = 5 or 21.7% ) among them could offer an infirmary . 

therefore , the screening was performed at other sites ( e.g. , offices , 
 canteens , dressing rooms ) for the remaining soccer clubs .
a fixed telephone line was available only at 17 sites ( 73.9% ) , whereas a gsm signal was present everywhere .
the physical characteristics of the 506 soccer players who were examined are shown in table 1 .
taking into account the importance of the family history in identifying athletes at risk of sudden death during sports , we found that 28.3% of the athletes had a family history 
 of cardiovascular disease .
concerning their personal history , 8.1% of the 
 athletes reported symptoms such as chest pain or discomfort during exercise . 
 from the physical examination ,
mild ( 1/6 ) systolic murmurs were found in 15.2% 
 and hypertension ( brachial blood pressure
. a total of 142 ecgs were transmitted either by pots ( n = 108 or 76% ) or gsm ( n = 34 or 24% ) .
ecg transmission on the first attempt was 
 achieved in 93% and 91% of the cases , respectively .
the ecg transmission was 
 deemed unsuccessful in case of disconnects due to technical difficulties .
the 
 mean time for recording and storing the ecg was 180  s ( sd 46 ) .
the transmission time was 60 seconds ( sd 23 ) depending on the file size , which ranged between 6 and 11  kb .
the above mean transmission time also includes repeated attempts.the mean connection 
 time was 24 sesconds ( sd 4 ) .
the high rate of transmission failure was due to the low reliability of pots connection or bad reception level in the case of gsm data calls ( table 2 ) . 

additionally , there was a weak but significant correlation coefficient between the reception 
 level and the number of failed transmissions ( r = 0.66 , p < .005 ) . at the end of each day ,
the cardiologist at the 
 laboratory of sports medicine examined the records and the ecgs of the athletes 
 tested during the day .
there was no disagreement between the cardiologist and 
 the gp on the ecgs that were not sent .
with regard to the transmitted clinical 
 records and ecgs , the cardiologist at the laboratory of sports medicine , who had 
 monitored and examined them , agreed only in 74 cases with the gp in the 
 playfield on the need to have sent the ecgs due to the existence of suspicious 
 findings .
however , from the 74 cases , 16 athletes were not referred for further 
 cardiovascular assessment as the cardiologist diagnosed that the findings were 
 without clinical significance . from the remaining 58 cases ,
49 athletes were 
 referred for echocardiography , 7 were subjected to a stress test , and 2 to a 
 24-hour ambulatory holter monitoring . 

after further evaluation , all of them were , eventually , permitted to 
 participate in physical activities .
our results indicate that telecardiology and specifically tet , interpreted by a sports medicine centre - based cardiologist , allows a rapid assessment of athletes at risk of adverse events during 
 exercise , without the presence of a sports cardiologist.thereby , qualitative care at lower cost can 
 be provided to a large population and can improve compliance.it is also shown that utilizing 
 the advancement of telecommunications , gsm transmission of ecg , is reliable and flexible , and 
 can be used as an alternative when there are no facilities .
several studies have already proven that tet is useful and reliable , and can provide early diagnostic information in cardiac patients with symptoms such as chest pain , dyspnea , palpitations , and so forth , 
 [ 1116 ] . 

so far , the cellular telephone communication system has been 
 used to transmit 12-lead ecgs from ambulances to a hospital [ 3 , 5 ] , especially in case of chest pain . 
 however , this is the first study introducing tet in sports medicine and specifically in the 
 preparticipation screening of athletes . in this study ,
a store - and - forward transmission method was used.alternatively , 
 real - time transmission could have been used , which , however , would have required a larger bandwidth 
 and would cost more.it should be mentioned here that wired broadband services are not widely available in greece.indeed , in 2005 , about 67% of home internet connections were still dial - up connections on the pstn ( public switched telephone network ) .among midband solutions , 
 isdn is more popular with 21% and adsl is gaining in popularity ( 8% ) very 
 slowly , mainly due to the high prices.on the other hand , most mobile operators in greece provide a general packet radio service ( gprs ) with higher data transfer rates within urban areas , but a 
 financial analysis must be done before one moves towards this solution , due to 
 the different way of charging ( per data volume , instead of calling time ) and 
 the initial cost of equipment .
it is worth comparing the results of the current study with a similar one in the literature , which was conducted in athens , greece .
reported that the mean 
 connection time between the telemedicine unit and the base unit was 28 seconds , 
 a value that is very close to the one reported here .
they also mention a success rate of 93% for 
 the first attempt , which compares very well with the 91% of our study .
one important difference between the two studies is the achieved data throughputs , which is about the double in 
 kyriacou et al . , but this could be attributed to the service used , since the authors mention the high speed circuit switched data ( hscsd ) , which offers high data 
 transfer rates.two more points are worth mentioning from our work : first , the 
 reception level was correlated with the efficiency of the gsm data link and , 
 second , the small mean total time needed to test each subject , that is , 
 four minutes for recording , storing , and transmitting the ecg .
one shortcoming of the study , which needs to be addressed in its future follow - ups , was that it 
 did not consider checking the accuracy of transmission .
one way would have been 
 for the cardiologist to have compared , at the end of the day , the received ecgs 
 against their print - outs from the portable electrocardiograph and not just reviewing 
 all the printed ecgs . in conclusion ,
it managed to distinguish the cases , which required further examination , and significantly reduced the logistics effort needed for the examination of all the subjects at the specialized medical 
 centre .
however , before it can be claimed that the procedure used in the 
 present study can be generalized to other forms of preparticipation screening , 
 a more careful cost - benefit analysis and an accuracy checking need to be performed .
 transtelephonic electrocardiographic transmission ( tet ) is the most widespread form of telecardiology since it enables clinicians to assess patients at a distance . 
 the purpose of this study was to assess the efficacy and effectiveness of tet either by fixed telephone line ( pots ) or by mobile phone in the preparticipation screening of young athletes . 
 a total of 506 players , aged 20.5  6.2 years , from 23 soccer clubs in the prefecture of thessaloniki , greece , were physically examined in their playfields by a general practitioner ( gp ) and had their ecg recorded .   in 142 cases , and on the judgment of the gp , 
 the ecg was transmitted via pots and/or global system for mobile communications ( gsm ) to a specialised medical centre where it was evaluated by a cardiologist .   
 the mean total time for recording , storing , and transmitting the ecg was four minutes per subject .   
 it was found that the success rate for transmission at first attempt was similar for both fixed and mobile networks , that is , 93% and 91% , respectively .   
 the failure rate in the gsm network was correlated to the reception level at the site of transmission .   only in about half ( n = 74 ) of the transmitted ecgs 
 did the cardiologist confirm  abnormal  
 findings , although in 16 , they were considered to be clinically insignificant .   
 consequently , 58 athletes were referred for further medical examination .   
 our results indicate that tet ( either by fixed telephone line or by mobile phone ) can ensure valid , reliable , and objective measurements , and significantly contribute to the application of medical screening in a great number of athletes . 
 therefore , it is recommended as an alternative diagnostic tool for the preparticipation screening of athletes living in remote areas . 
1. INTRODUCTION
2. METHODS
3. RESULTS
4. DISCUSSION