Dizziness and two near-faints since this morning

2026-09-14

The case

78-year-old man. Dizziness and two near-faints since this morning

Lives alone and independent. Treated hypertension on amlodipine only — no beta blocker, no rate-limiting calcium blocker, no digoxin and no antiarrhythmic. No chest pain and no palpitations. Each episode came on standing at the sink: a few seconds of going grey and light-headed, no warning, no loss of consciousness and no injury.

On arrival

HR: 78
SpO₂ (%): 97
Respiratory rate: 16
Temperature (°C): 36.5
Systolic BP (mmHg): 138
Diastolic BP (mmHg): 76

Stage 1 of 2

He is comfortable and fully orientated, lying on the trolley. Heart sounds are normal, chest is clear, there is no murmur and no postural drop. This twelve-lead was recorded four minutes after he arrived, between episodes.

Tracing 1 of 2 for the quiz “Dizziness and two near-faints since this morning”. — Twelve-lead on arrival, 25 mm/s, 10 mm/mV. Open this tracing in the studio

What does this tracing show?

ARate-related aberrant conduction, of no immediate consequence Your answer
BRight bundle branch block, unchanged throughout the recording Your answer
CBundle branch block that alternates between right and left, with a run of complete AV block Correct answer Your answer
DAtrial fibrillation with a slow ventricular response Your answer

Stage 2 of 2

He is put on the monitor. Twenty minutes later he says he feels grey again; the monitor records a 4.2-second pause before a slow escape returns. He does not lose consciousness. Bloods are back: potassium 4.2, magnesium 0.86, creatinine 94, troponin T 9 ng/L and TSH normal. He has taken nothing but amlodipine.

Tracing 2 of 2 for the quiz “Dizziness and two near-faints since this morning”. — Rhythm strip, 25 mm/s, 10 mm/mV. Open this tracing in the studio

Bloods

Troponin T (ng/L): 9
Magnesium (mmol/L): 0.86
Potassium (mmol/L): 4.2
Creatinine (umol/L): 94

Notes

Monitored pause 4.2 s, symptomatic. No AV-nodal blocking drug taken.

What does this commit you to?

AAtropine, and discharge if the dizziness settles Your answer
BDischarge with a 24-hour Holter and cardiology follow-up Your answer
COutpatient echocardiogram first, and decide about pacing on the result Your answer
DAdmit to a monitored bed and refer for permanent pacing Correct answer Your answer

Diagnosis

Alternating bundle branch block with intermittent complete AV block

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This tracing was generated, not recorded. It opens in the studio with every dial live.

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Discussion

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