Relate the surface electrocardiogram (ECG) to the events of the cardiac cycle (60% of marks). Briefly describe the mechanism of the effects of digoxin, and the mechanism of the effects of amiodarone, on the ECG (40% of marks)
Candidates were expected to provide sufficient detail in answers. Extra marks were
awarded for diagrams relating the ECG accurately to pressure events during the
cardiac cycle. Time intervals, units of measurement and clear labels were essential
Mechanisms pertaining to ion flux and ion channels needed to be specifically
explained. Discussion of mechanisms needed to be accurate and relevant to the
effect on the ECG. For example, better answers noted that AV conduction was
depressed by Digoxin, predominantly due to an increase in Vagal tone
Syllabus: Cib2c C2c2b
Recommended sources: Principles of Physiology for the Anaesthetist, Power and
Kam, pages 107-110, Pharmacology and Physiology in Anaesthetic Practice,
Relationship of cardiac cycle events and the ECG:
If one needed to expand on this:
Effects of digoxin on the ECG:
Effects of amiodarone on the ECG
Yates, Christopher, and Alex F Manini. "Utility of the electrocardiogram in drug overdose and poisoning: theoretical considerations and clinical implications." Current cardiology reviews 8.2 (2012): 137-151.
Antoni, H. "Electrophysiology of the heart at the single cell level and cardiac rhythmogenesis." Comprehensive Human Physiology. Springer, Berlin, Heidelberg, 1996. 1825-1842.
Pinnell, Jeremy, Simon Turner, and Simon Howell. "Cardiac muscle physiology." Continuing Education in Anaesthesia, Critical Care and Pain 7.3 (2007): 85-88.
Harley, Alexander, C. Frank Starmer, and Joseph C. Greenfield. "Pressure-flow studies in man. An evaluation of the duration of the phases of systole." The Journal of clinical investigation 48.5 (1969): 895-905.
Braunwald, Eugene, ALFRED P. FISHMAN, and AndrÉ Cournand. "Time relationship of dynamic events in the cardiac chambers, pulmonary artery and aorta in man." Circulation research 4.1 (1956): 100-107.
Singh, V., et al. "Amiodarone Induced Variety of ECG Changes-A Beginners ECG Delight." J Clin Exp Cardiolog 6.2 (2015).