Dysrhythmias III

Cardiovascular System

{"ops":[{"insert":"An 18-year-old man is seen at a university clinic in South Florida for a pre-participation sports physical. He was on the cross-country track team in high school. He has been in good health, reports no symptoms, and denies recent travel out of the area. The physical examination is within normal limits. A routine electrocardiogram (ECG) is obtained and shows a heart rate of 58 and a PR interval of 300 milliseconds. The ECG is otherwise within normal limits.\n\nWhich of the following is the most likely cause of the prolonged P-R interval?"},{"insert":"\n"}]}




Left ventricular hypertrophy




Tricuspid valve abnormality


Subacute infective endocarditis


Increased vagal tone


{"ops":[{"insert":"CORRADO D., PELLICCIA A., HEIDBUCHEL H., SHARMA S., LINK M., BASSO C., BIFFI A., BUJA G., DELISE P., GUSSAC I., ANASTASAKIS A., BORJESSON M., BJORNSTAD H. H., CARRE F., DELIGIANNIS A., DUGMORE D., FAGARD R., HOOGSTEEN J., MELLWIG K. P., PANHUYZEN-GOEDKOOP N., SOLBERG E., VANHEES L., DREZNER J., ESTES N.A. M., ILICETO S., MARON B. J., PEIDRO R., SCHWARTZ P. J., STEIN R., THIENE G., ZEPPILLI P., MCKENNA W. J.. Recommendations for interpretation of 12-lead electrocardiogram in the athlete. European Heart Journal [online] December, 31(2):243-259 [viewed 17 November 2019] Available from: doi:10.1093\/eurheartj\/ehp473"},{"insert":"\n","attributes":{"list":"ordered"}},{"insert":"ARO AL, ANTTONEN O, KEROLA T, JUNTTILA MJ, TIKKANEN JT, RISSANEN HA, REUNANEN A, HUIKURI HV. Prognostic significance of prolonged PR interval in the general population. Eur Heart J [online] 2014 Jan, 35(2):123-9 [viewed 17 November 2019] Available from: http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/23677846"},{"insert":"\n","attributes":{"list":"ordered"}},{"insert":"PALMER BF, CLEGG DJ. Diagnosis and treatment of hyperkalemia. Cleve Clin J Med [online] 2017 Dec, 84(12):934-942 [viewed 17 November 2019] Available from: http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/29244647"},{"insert":"\n","attributes":{"list":"ordered"}},{"insert":"HOLST KA, CONNOLLY HM, DEARANI JA. Ebstein\u0027s Anomaly Methodist Debakey Cardiovasc J [online] 2019 Apr-Jun, 15(2):138-144 [viewed 17 November 2019] Available from: http:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6668741"},{"insert":"\n","attributes":{"list":"ordered"}},{"insert":"MURRAY TS, SHAPIRO ED. Lyme Disease Clin Lab Med [online] 2010 Mar, 30(1):311-328 [viewed 17 November 2019] Available from: http:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC3652387"},{"insert":"\n","attributes":{"list":"ordered"}}]}

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