Sudden palpitations and light-headedness on the assessment unit

2026-08-17

The case

71-year-old woman. Sudden palpitations and light-headedness on the assessment unit

Anterior myocardial infarction six years ago, treated with primary PCI to the LAD. Takes bisoprolol, ramipril, atorvastatin and aspirin. Admitted this morning with two weeks of exertional breathlessness.

On arrival

HR: 168
SpO₂ (%): 94
Respiratory rate: 26
Temperature (°C): 36.4
Systolic BP (mmHg): 78
Diastolic BP (mmHg): 50

Stage 1 of 2

Marta Sokolová is grey and sweating, rousable but slow to answer. The nurse who called you says it started four minutes ago while she was sitting up for lunch. Radial pulse is impalpable, femoral pulse present.

Tracing 1 of 2 for the quiz “Sudden palpitations and light-headedness on the assessment unit”. — Twelve-lead recorded at the bedside, 25 mm/s, 10 mm/mV. Open this tracing in the studio

What is the rhythm on this tracing?

ATorsades de pointes Your answer
BMonomorphic ventricular tachycardia Correct answer Your answer
CSupraventricular tachycardia with rate-related aberrancy Your answer
DPre-excited atrial fibrillation Your answer

What is the immediate treatment?

ASynchronised DC shock under sedation Correct answer Your answer
BUnsynchronised shock at maximum energy Your answer
CAdenosine 6 mg by rapid intravenous push Your answer
DVerapamil 5 mg intravenously over two minutes Your answer

Stage 2 of 2

She converts on the first shock and is awake and talking within a minute. Potassium is 4.3 mmol/L and magnesium 0.86 mmol/L. This tracing was recorded once she had settled.

Tracing 2 of 2 for the quiz “Sudden palpitations and light-headedness on the assessment unit”. — Twelve-lead repeated after cardioversion, 25 mm/s, 10 mm/mV. Open this tracing in the studio

Observations

HR: 78
SpO₂ (%): 97
Respiratory rate: 16
Temperature (°C): 36.5
Systolic BP (mmHg): 118
Diastolic BP (mmHg): 70

Bloods

Magnesium (mmol/L): 0.86
Potassium (mmol/L): 4.3

What does the second tracing show?

ALeft bundle branch block, which accounts for the width of the first tracing Your answer
BAcute anterior infarction: the arrhythmia was ischaemic in origin Your answer
COld anterior infarction: Q waves in V1 to V3 without acute ST change Correct answer Your answer
DPoor R-wave progression from high precordial lead placement Your answer

Diagnosis

Monomorphic ventricular tachycardia on an old anterior infarct scar

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Discussion

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