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A 50 year old woman with a history of end stage non-ischaemic cardiomyopathy presents with two days of increasing dyspnoea at rest and orthopnoea. The patient was hypoxic, hypotensive, and tachycardic. Clinically, the patient was felt to have decompensated heart failure so she was admitted to the cardiac intensive care unit for haemodynamic monitoring and management.
Invasive haemodynamic monitoring and intensive medical treatments were initiated. Despite maximal medical treatment the patient did not improve, so a more invasive strategy to provide haemodynamic support was pursued. The figures here demonstrate haemodynamic tracings (below) and a schematic representation (right) of one such invasive device used for haemodynamic support.
The tracings below depict simultaneous ECG, radial arterial pressure tracing, pulmonary artery pressure tracing, and central venous pressure tracing being monitored in the cardiovascular intensive care unit. The tracings show total dissociation between the radial arterial pressure tracing and the heart rhythm as denoted by the ECG. While the radial arterial waveform shows no relation to the ECG, the right heart pressures as recorded by the pulmonary artery pressure and the central venous pressure are synchronous with the ECG. The reason for the dysynchrony between the radial arterial pressure and the intrinsic cardiac cycle is a mechanical left ventricular assist device (LVAD) has been implanted. The LVAD in demand mode cycles when it fills, with timing that is independent of the native cardiac cycle. Thus the radial arterial pressure waveforms have timing that is independent of the native right sided circulation and the intrinsic cardiac rhythm.