Two-dimensional echocardiographic features of echinococcosis of the heart and great blood vessels. Clinical and surgical implications.

Echocardiographic findings in cardiac echinococcosis have been previously described in isolated cases, but no detailed account of the various echocardiographic aspects and their clinical and surgical implications have ever been reported. We present a retrospective analysis of the two-dimensional echocardiograms of 15 patients with hydatid cysts affecting the heart or great blood vessels. Two-dimensional echocardiogram features were compared with the main clinical syndromes. Surgical confirmation of the echocardiogram findings was available in 12 patients. The cyst sizes ranged from 0.5 to 12 cm in diameter. Eleven patients had single cysts, three patients had two cysts, and one patient had multiple cysts. Cysts were located in the intramyocardial region in nine patients, the pericardial in three, and the paracardial in another three. All intramyocardial cysts protruded into the adjacent cardiac chamber, but in only two patients was there significant tricuspid valvular dysfunction. Pericardial and mediastinal cysts showed compression of cardiac chambers or great blood vessels, and two cysts had ruptured into the descendent thoracic aorta or inferior vena cava. In most patients, two-dimensional echocardiographic images of hydatid cysts were those of a cystic mass having well-defined edges and internal trabeculations corresponding to daughter membranes. However, in four patients, two-dimensional echocardiographic images showed a "solid" mass instead of a cystic mass, and in one patient with the multivesicular variety of echinococcosis, the images showed a large mass with poorly defined edges having a honeycombed appearance causing lysis of the anterior arch of the second and third left ribs. The two-dimensional echocardiographic finding showed good correlation with main clinical syndromes, but anaphylactic reactions occurred in every cyst location. In one patient, postoperative two-dimensional echocardiography showed two small intramyocardial cysts that had not been noticed during preoperative two-dimensional echocardiography or during surgical examination. Pathological examination in the four patients with a solid mass showed replacement of the hydatid liquid by necrotic matter containing membrane residues with a foreign-body inflammatory reaction of a granulomatous type. In conclusion, two-dimensional echocardiography is a very useful tool for diagnosis and management of patients with cardiac echinococcosis, but the great diversity of findings regarding number, size, location, and appearance of cysts must be borne in mind to interpret correctly the two-dimensional echocardiograms.

Fascicular block within the His bundle.

The findings in a patient with complete atrioventricular block and normal morphology and duration of the QRS complex are presented. A His bundle electrogram was obtained, which led to the location of the atrioventricular block within the His bundle. A careful review of the electrocardiograms obtained during the seven years preceding the onset of complete atrioventricular block showed a QRS complex with the features of left anterior hemiblock and a progressive impairment of atrioventricular conduction. From these data, we inferred that the different degrees of atrioventricular block and the left anterior hemiblock were caused by lesions within the His bundle involving the fibers destined for the left anterior division of the left branch. After the onset of complete atrioventricular block, with the subsidiary pacemaker located in the His bundle distal to the lesions, the QRS complex became normal, indicating the integrity of the bundle branches and fasciculi. The atrial and proximal His potential intervals and those between distal His and ventricular potentials were normal.