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electrocardiogram (ECG, EKG)

A graphic record of the electrical activity of the heart, obtained with an electrocardiograph. * see figure Indications: 1) new symptoms or changes in symptoms a) syncope, pre-syncope or cardiac arrest b) chest pain, possibly cardiac in origin c) change in usual pattern of angina pectoris d) acute pulmonary edema e) acute congestive heart failure f) post-thrombolytic chest pain g) new or worsening dyspnea h) *unexplained weakness, fatigue or prostration i) *unexplained cough or hemoptysis j) palpitations 2) new signs or changes in signs a) worsening congestive heart failure b) bradycardia, tachycardia, irregular pulse or new onset of cardiac arrhythmia c) post-thrombolytic hypotension d) unexplained hypotension in an adult e) coma, altered mental status or CVA f) new murmur or friction rub g) new findings suggesting pulmonary hypertension 1] elevated jugular venous pressure 2] dependent edema 3] hepatomegaly h) poorly controlled hypertension i) valvular heart disease - *fever of unknown origin j) suspected drug overdose k) blunt chest trauma with precordial injury l) electrolyte abnormalities m) hypothermia n) renal failure o) diabetic ketoacidosis 3) abnormal physical findings a) cardiomegaly b) seizures c) congenital deafness d) carotid, cranial or abdominal bruit e) increased intracranial pressure 4) pre-operative management (general anesthesia) a) *patients over 40 years, or b) known cardiac disease 5) post event monitoring a) complications of myocardial infarction b) postoperative complication 6) routine risk assessment in the elderly ? [4] * most arrhythmias are intermittent & not recorded on a resting ECG [6] Contraindications: - routine screening in the young people [5] - routine screening in asymptomatic adults at low risk for cardiovascular events [6]* * routine screening still common in low-risk patients [7] - these patients underwent significantly more cardiac tests, with no evidence of benefit [7] Procedure: - voltage calibration: 10 mm = 1 mV - time calibration: 1 mm = 40 msec, 25 mm/sec Notes: - computer algorithms not always correct [3] - ingestion of a single AA battery led to ECG findings consistent with acute ST-segment-elevation myocardial infarction in a 26-year-old prison inmate [8] - EKG Interpretations: A Non-Cardiologist Must Know (video) [9]

Related

cardiac (ECG) monitor ECG changes in myocardial ischemia ECG lead electrocardiogram feature HOLTER

Specific

microvolt T-wave alternans microvolt testing (MTWA) signal averaged electrocardiogram (SA-ECG)

General

cardiology electrophysiologic measurement

Figures/Diagrams

EKG: normal sinus rhythm Electrocardiograms

References

  1. Diagnostic History & Physical Examination in Medicine, Chan & Winkle, Current Clinical Strategies, Laguna Hills, CA 1996
  2. Practial ECG Interpretation, Basic Electrocardiography & Cardiac Arrhythmias, T. Evans, M.D., UCSF, Ring Montain Press, 1998
  3. Journal Watch 24(24):183, 2004 Bogun F, Anh D, Kalahasty G, Wissner E, Bou Serhal C, Bazzi R, Weaver WD, Schuger C. Misdiagnosis of atrial fibrillation and its clinical consequences. Am J Med. 2004 Nov 1;117(9):636-42. PMID: 15501200
  4. Auer R et al. Association of major and minor ECG abnormalities with coronary heart disease events. JAMA 2012 Apr 11; 307:1497 PMID: 22496264 - Greenland P. Should the resting electrocardiogram be ordered as a routine risk assessment test in healthy asymptomatic adults? JAMA 2012 Apr 11; 307:1530. PMID: 22496268
  5. Maron BJ et al Assessment of the 12-Lead ECG as a Screening Test for Detection of Cardiovascular Disease in Healthy General Populations of Young People (12-25 Years of Age): A Scientific Statement From the American Heart Association and the American College of Cardiology. Circulation. Sept 15, 2014
  6. Medical Knowledge Self Assessment Program (MKSAP) 17, 18. American College of Physicians, Philadelphia 2015, 2018.
  7. Bhatia RS, Bouck Z, Ivers NM et al. Electrocardiograms in low-risk patients undergoing an annual health examination. JAMA Intern Med 2017 Jul 10 PMID: 28692719
  8. Giannasi G et al Acute ST-Segment Elevation From an Ingested Battery: A Case Report. Ann Intern Med. 2020. Nov 24, PMID: 33226857 https://www.acpjournals.org/doi/10.7326/L20-1123
  9. Schurmann P EKG Interpretations: A Non-Cardiologist Must Know Houston Methodist DeBakey Heart and Vascular Center https://www.vumedi.com/video/ekg-interpretations-a-non-cardiologist-must-know/