[First degree atrioventricular block caused by a calcified tumor of the atrioventricular septum]. / Atrioventrikulski blok prvog stupnja prouzrocen kalcificiranom tumorskom tvorbom atrioventrikulskog septuma.

First degree atrioventricular block occurred in a 69-year-old patient with a calcified atrioventricular septum tumour. The patient suffered several episodes of syncope and the only abnormality found in the routine clinical work-up was a remarkable first degree atrioventricular block. The echocardiogram, computed tomography (CT) and the magnetic resonance imaging (MRI) procedure showed a calcified tumour in the posterior part of the left ventricle, between the left atrium and left ventricle, just beneath the aortic root spreading to the interventricular septum. It was suggested that the first degree atrioventricular block was caused by the tumour. The symptoms were relieved by implantation of permanent cardiac pacemaker.

Subcostal M-mode echocardiography of the right atrial wall in evaluation of cardiac arrhythmias and pacing.

Subcostal M-mode echocardiography of the right atrial wall in combination with the simultaneously recorded nondiagnostic electrocardiogram is useful in the recognition of various rhythm disturbances. Each arrhythmia has a characteristic right atrial wall motion pattern. Flat and hidden P-waves can be accurately detected throughout the cardiac cycle and supraventricular tachycardias with aberration can be distinguished from ventricular tachycardia with AV dissociation. This echocardiographic technique is of special value in the follow-up of physiological pacemakers because atrial capture and sensing malfunctions can be reliably detected. Finally, it can also facilitate the programming of atrial channels output + sensitivity, and recognition of the pacemaker syndrome.

Noninvasive detection of insulation break.

The electric current leak through an unsealed connector or insulation break can be a source of problems in cardiac pacing. This study describes a method of leak detection. The underdrive inhibition test--chest wall stimulation with external stimulator (ES)--was used for this purpose. Three cutaneous electrodes (CE) were applied: the first one above the indifferent electrode, the second one above the suspected leak location, and the third one above the active electrode. Two inhibition thresholds (IT) were measured: the first one connecting ES on first CE and second CE, and the second one connecting ES on first CE and third CE. The inhibition threshold is the value of ES output charge at which the inhibition of implanted pacemaker occurs. The relation between two ITs, not the absolute value, is significant for leak estimation. The former should be at least five times higher than the latter, if there is no current leak. During the two years of follow-up of 541 patients, 272 measurements were performed. In 52 cases the connector leak was found-both ITs were approximately equal. Twenty-seven cases were confirmed by surgery for EOL pacemaker replacement; the intrusion of body fluid was evident. Five operations were indicated because of the leak problem: two--muscle twitching, one--loss of capture, one-undersensing, and one--insulation break with lead fracture. The method, although approximate, is a reliable qualitative estimation of leak.