Test Yourself
Case 1
A 42 year old male attends his GP for a routine medical assessment as part of his work offshore. He has no previous past medical history, is not taking any regular medications and has no chest pain or other respiratory. symptoms. However, he has noticed that over the last few days he has experienced palpitations intermittently.
SH: drinks alcohol occasionally, non-smoker
His ECG is shown below.
Q1) What is this patient's heart rate? (1 mark)
Q2) Explain why some QRS complexes are wide and some are narrow (2 marks)
Q3) What arrhythmia is noted in the above ECG (1 mark)
Q4) Does this rhythm warrant underlying investigation? Explain your answer (2 marks)
Answers
Q1) 80bpm (must use method of counting the number of QRS complexes occurring in the space of six seconds (30 large squares) and multiplying the answer by 10 to get the number of beats in 60s - alternative method should not be used at the heart rhythm is irregular)
Q2) Narrow QRS complexes occur when the electrical signals travel via the His-purkinje system (1 mark). Broad QRS complexes occur whenever electrical conduction through the ventricles is slowed (1 mark) e.g. signal not travelling via his-purkinje system or cells taking longer to depolarise e.g. metabolic disturbances (1 mark). (Max 2 marks)
Q3) Ventricular Trigeminy (need both terms "ventricular" and "trigeminy" for full mark, award 1/2 mark for trigeminy alone)
Q4) No (1 mark), Ectopic beats are not concerning in young people with no history of ischaemic heart disease and patients with a normal QT interval (1 mark)
