Abstract
A case of sudden cardiac arrest caused by intra-His bundle block with massive mitral annular calcification in a diabetic uremic patient is presented.
A 75-year-old male who had been undergoing hemodialysis for three years was admitted with a syncopal attack. His serial electrocardiograms taken once a month and Holter monitoring examined once a year had been interpreted as within normal limits since the beginning of hemodialysis. Although parathyroid hormone level had been within normal limits, the calcium-phosphorus product had often been more than 60, with a maximum value of 80. On admission he regained consciousness and the electrocardiogram showed a normal tracing. However, cardiac arrest occurred unexpectedly on the ward and continued despite artificial respiration and cardiac massage. The patient recovered consciousness and spontaneous respiration soon after an artificial pacemaker was implanted. According to subsequent electrophysiologic studies, although the His bundle electrocardiogram showed a splitting His wave without pacing, complete atrioventricular block was induced by 130beats/min atrial pacing and second degree atrioventricular block continued after the atrial pacing was turned off. With two-dimensional and Doppler echocardiography, massively calcified mitral annules and valve with a restricted opening were visible. A diagnosis of intra-His bundle block secondary to massive mitral annular calcification was established and a permanent pace maker was implanted.
This case, in which cardiac arrest was not predicted by frequent examination of serial electrocardiograms, strongly suggests the importance of electrophysiological studies in uremic patients with massive mitral annular calcification.
