1. Introduction to electrocardiography
Jonathan Sahu
Consultant Cardiologist
Honorary Senior Lecturer
Sheffield University

2. 75 yo male admitted with chest pain

3. 70 yo female with chest pain and syncope

4. 40 yo male with recurrent syncope

5. 80 yo lady with syncope

7. His-Purkinje system

8. History
1600 – William Gilbert introduces the term “electrica” for objects (insulators) that hold static electricity. He derived the word from the greek for amber – electra
1646 – Thomas Brown is the first to use the word “electricity”: “Electricity, that is, a power to attract strawes or light bodies, and convert the needle freely placed” from Pseudodoxia Epidemica
1786 – Luigi Galvani showed that electrical stimulation of the frog heart lead to cardiac muscle contraction. “Galvanometer – machine for measuring (and recording) electricity – this is what an ECG/EKG is – a very sensitive galvanometer!
1792 – Alessandro Volta tries to disprove Galvani’s “animal electricity theory”
Over the19th century – development of more sensitive instruments to detect the small electrical currents within the heart

9. History
1838 – Italian scientist Carlo Matteucci realises that electricity is associated with the heart beat; “rheoscopic frog” model
1843 – German Physiologist Emil Du Bois-Reymond describes an “action potential” accompanying each muscular contraction
1876 – Irish scientist Marey records the electrical activity of an exposed frog heart using an “electrometer”
1887 – Augustus Waller published the first human electrocardiogram (St Mary’s Hospital, London) using a capillary electrometer

10. History
1890 – Burch devises an arithmetical correction for the observed fluctuations of the electrometer which allowed the true waveforms to be seen
1893 – Dutch Physiologist Willem Einthoven introduces the term “electrocardiogram”
1895 – Einthoven, using an improved electrometer and the correction formula (Burch), describes and names the 5 derived deflections: P, Q, R, S and T waves

11. Why PQRST? Original deflections were labelled ABCD
Mathematical convention dating back to Descartes using the second half of the alphabet; N has other meanings in mathematics and O was used for the origin of Cartesian coordinates. Einthoven chose the next letter of the alphabet!

12. History
1906 – using the string electrometer Einthoven diagnoses some cardiac problems (LVH, RVH)
1906 – Cremer records the first Oesophageal electrocardiogram
1907 – Cushny publishes the first case report of AF
1911 – Thomas Lewis publishes “The mechanism of the heart beat”
1912 – Einthoven describes the equilateral triangle (Einthoven’s triangle) formed by his standard leads I, II and III.
1924 – Einthoven receives Nobel Prize for Medicine for inventing the electrocardiogram
1938 – AHA and Cardiac Society of GB define the position of the chest leads – V1-V6 (“V” standing for voltage)
Goldberger increased Wilson’s unipolar lead voltage by 50% and described the augmented leads
1949 – Norman Holter ambulatory ECG

83. Contribution of individual membrane currents

84. Contribution of individual membrane currents

85. HPS

86. QRS – initial septal depolarisation

88. RBBB

89. RBBB

90. RBBB

92. LBBB

93. LBBB

94. LBBB