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Progressive exertional breathlessness and one episode of near-syncope

The case

35-year-old woman. Progressive exertional breathlessness and one episode of near-syncope

Systemic sclerosis with known pulmonary arterial hypertension. No sudden pleuritic pain and no acute change in symptoms.

On arrival

HR
104
GCS
15
SpO₂ (%)
94
Respiratory rate
20
Temperature (°C)
36.5
Systolic BP (mmHg)
108
Diastolic BP (mmHg)
68

Stage 1 of 1

She is stable at rest. The ECG is recorded during routine assessment of worsening exercise tolerance.

The tracing for the quiz “Progressive exertional breathlessness and one episode of near-syncope”.
Twelve-lead recorded on arrival, 25 mm/s, 10 mm/mV. Open this tracing in the studio
What chamber abnormality is shown?

The tracing shows right axis deviation at about 150 degrees with a dominant R wave in V1 and deep S waves persisting across the lateral precordial leads, which together indicate right ventricular hypertrophy. A posterior myocardial infarction can produce a tall R in V1, but it would be accompanied by ST depression in V1 to V3 as a reciprocal change, which is absent here. The axis and the overall morphology point to a pressure-loaded right ventricle rather than a posterior infarct or left-sided pathology.

Which combination is most characteristic?

Right axis deviation beyond 110 degrees combined with a dominant R wave in V1 is the hallmark pair for right ventricular hypertrophy on a twelve-lead ECG. Both features are visible on this tracing: the axis is about 150 degrees and V1 shows a tall R wave exceeding the S wave. Left axis deviation with deep S waves in V1 would suggest left anterior fascicular block, and broad notched R waves in V6 would point to left bundle branch block, neither of which fits this pattern.

What does the associated tall P-wave morphology suggest?

The tall, peaked P waves visible in the inferior leads exceed 2.5 mm and represent P pulmonale, indicating right atrial enlargement from chronic pressure loading. In a patient with pulmonary arterial hypertension, this is the expected atrial response to a sustained increase in right-sided filling pressures. Hyperkalaemia can produce peaked waves but affects the T wave rather than the P wave, and pre-excitation produces a delta wave at the onset of the QRS, not a change in P-wave morphology.

Diagnosis

Right ventricular hypertrophy and strain from pulmonary arterial hypertension

This tracing shows the classic ECG pattern of right ventricular hypertrophy with strain in a patient with pulmonary arterial hypertension complicating systemic sclerosis. The combination of right axis deviation, a dominant R wave in V1 and peaked P waves in the inferior leads tells a single story: chronically elevated pulmonary artery pressure has remodelled first the right atrium and then the right ventricle.

The practical point is that these changes develop over months to years. In a patient with known pulmonary hypertension, worsening exercise tolerance with this pattern should prompt reassessment of pulmonary pressures and right ventricular function rather than a search for a new diagnosis.

References

  1. Hancock EW, Deal BJ, Mirvis DM, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part V: electrocardiogram changes associated with cardiac chamber hypertrophy. Circulation. 2009;119(10):e251-e261.
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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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