{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T22:38:04Z","timestamp":1791844684900,"version":"4.3.4"},"reference-count":27,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"25","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[2020,12,22]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>The diagnosis of long QT syndrome (LQTS) is rather straightforward. We were surprised by realizing that, despite long-standing experience, we were making occasional diagnostic errors by considering as affected subjects who, over time, resulted as not affected. These individuals were all actively practicing sports\u2014an observation that helped in the design of our study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>We focused on subjects referred to our center by sports medicine doctors on suspicion of LQTS because of marked repolarization abnormalities on the ECG performed during the mandatory medical visit necessary in Italy to obtain the certificate of eligibility to practice sports. They all underwent our standard procedures involving both a resting and 12-lead ambulatory ECG, an exercise stress test, and genetic screening.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      There were 310 such consecutive subjects, all actively practicing sports with many hours of intensive weekly training. Of them, 111 had a normal ECG, different cardiac diseases, or were lost to follow-up and exited the study. Of the remaining 199, all with either clear QTc prolongation and\/or typical repolarization abnormalities, 121 were diagnosed as affected based on combination of ECG abnormalities with positive genotyping (QTc, 482\u00b135 ms). Genetic testing was negative in 78 subjects, but 45 were nonetheless diagnosed as affected by LQTS based on unequivocal ECG abnormalities (QTc, 472\u00b133 ms). The remaining 33, entirely asymptomatic and with a negative family history, showed an unexpected and practically complete normalization of the ECG abnormalities (their QTc shortened from 492\u00b137 to 423\u00b125 ms [\n                      <jats:italic>P<\/jats:italic>\n                      &lt;0.001]; their Schwartz score went from 3.0 to 0.06) after detraining. They were considered not affected by congenital LQTS and are henceforth referred to as \u201ccases.\u201d Furthermore, among them, those who resumed similarly heavy physical training showed reappearance of the repolarization abnormalities.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>It is not uncommon to suspect LQTS among individuals actively practicing sports based on marked repolarization abnormalities. Among those who are genotype-negative, &gt;40% normalize their ECG after detraining, but the abnormalities tend to recur with resumption of training. These individuals are not affected by congenital LQTS but could have a form of acquired LQTS. Care should be exercised to avoid diagnostic errors.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1161\/circulationaha.120.048916","type":"journal-article","created":{"date-parts":[[2020,10,19]],"date-time":"2020-10-19T05:01:56Z","timestamp":1603083716000},"page":"2405-2415","update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":58,"title":["Exercise Training-Induced Repolarization Abnormalities Masquerading as Congenital Long QT Syndrome"],"prefix":"10.1161","volume":"142","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1090-3292","authenticated-orcid":true,"given":"Federica","family":"Dagradi","sequence":"first","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin (F.D., C.S, S.C., L.C., P.J.S.)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1209-0157","authenticated-orcid":true,"given":"Carla","family":"Spazzolini","sequence":"additional","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin (F.D., C.S, S.C., L.C., P.J.S.)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9693-4083","authenticated-orcid":true,"given":"Silvia","family":"Castelletti","sequence":"additional","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin (F.D., C.S, S.C., L.C., P.J.S.)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0675-4845","authenticated-orcid":true,"given":"Matteo","family":"Pedrazzini","sequence":"additional","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics (M.P., M-C.K., L.C., P.J.S.)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9629-2172","authenticated-orcid":true,"given":"Maria-Christina","family":"Kotta","sequence":"additional","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics (M.P., M-C.K., L.C., P.J.S.)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8739-6527","authenticated-orcid":true,"given":"Lia","family":"Crotti","sequence":"additional","affiliation":[{"name":"Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin (F.D., C.S, S.C., L.C., P.J.S.)"},{"name":"Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics (M.P., M-C.K., L.C., P.J.S.)"},{"name":"Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital (L.C.), Milan, Italy."},{"name":"University of Milano-Bicocca, Department of 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