Evaluation Of Valve Prostheses And Pacemakers

The normal movements of cardiac valve prostheses are parallel between the two phases of the cardiac cycle. If a significant angle of tilt (more than 12°) is formed between the two phases, instability of the valve with associated regurgitation is nearly always present.2,29,32,34

The bileaflet St. Jude valve35 is used in both mitral and aortic positions. The valve is difficult to see radiographically (Fig. 12-28) but is readily detected under the fluoroscope.1,2,35 When the leaflets move sluggishly, thrombotic stenosis of the valve should be suspected. Rarely, one leaflet may dislodge and embolize distally, causing acute valvular regurgitation.35

Jude Valve Opening Angle Fluoroscopy

Figure 12-28: Patient with congenitally corrected transposition of the great arteries. The left-sided atrioventricular valve was replaced with a St. Jude prosthesis. The valve was caught in the opened position (in diastole), when both leaflets were seen as a pair of parallel lines (arrows). The same valve was invisible in the closed position (not shown).

Figure 12-28: Patient with congenitally corrected transposition of the great arteries. The left-sided atrioventricular valve was replaced with a St. Jude prosthesis. The valve was caught in the opened position (in diastole), when both leaflets were seen as a pair of parallel lines (arrows). The same valve was invisible in the closed position (not shown).

The position of the pacemaker can be determined promptly under the fluoroscope and recorded on film.236 The subepicardial fat line overlies the myocardium and underlies the pericardium. If the pacing catheter is found within the fat stripe, it may have passed through the coronary sinus and entered one of the major cardiac veins. If the tip of the catheter is seen outside the fat stripe, however, it may have perforated the myocardium and thus be lying in the pericardium or beyond.2 Although the wires and electrodes of a transmediastinal pacemaker may look normal on the films, minor breakage can be appreciated only in ventricular systole with the aid of fluoroscopy.36

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