Abstract
This case, involving a 74 year old man who underwent mitral valve and aortic valve replacements, provides detailed insight into the perioperative echocardiographic and haemodynamic changes occurring when a mitral valve prosthesis intermittently obstructs. It illustrates the early sequence of electromechanical dissociation which would lead to cardiac arrest should a tilting disc prosthesis be immobilised in the closed position. Keywords: prosthetic valve replacement; echocardiography; intermittent obstruction
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Figure 1 .
Concurrently recorded ECG, systemic radial arterial pressure, and central pulmonary arterial (PA) pressure tracings. The fourth, sixth, and 11th peak PA pressures step up from 54 mm Hg to 70 mm Hg but return directly to the base line. Before each peak, the resting diastolic PA pressure is elevated from 19 mm Hg to 28 mm Hg with a "flat line" appearance. The corresponding fourth, sixth and 11th radial artery waveforms dampen from 128/42 mm Hg to 86/38 mm Hg, again returning to the base line. Systemic arterial waveforms appear after the PA waveforms owing to the fractional time delay in transmission between the ascending aorta and measurement at the radial artery. Cardiac rhythm remains regular at 75 beats per minute (paper speed 12.5 mm/s).
Figure 2 .
Apical, four chamber, two dimensional views of mitral valve disc prosthesis (31 mm). (A) The disc pivots appropriately, casting acoustic shadows back into the left atrium. (B) Intermittently, a pronounced "billowing" of the septum occurs into the left ventricle. The prosthetic disc remains in the closed position. LV, left ventricle; RV, right ventricle; LA, left atrium, RA, right atrium.
Figure 3 .
Continuous wave Doppler cutting across both mitral prosthetic inflow signal (a) and the left ventricular outflow tract signal (b). There is abrupt loss of the fourth mitral signal (c), demonstrating absent flow into the left ventricle. Subsequent flow in the left ventricular outflow tract is reduced (d). The fifth mitral inflow signal (e) is augmented.
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
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