The antemortem diagnosis of myocardial sarcoidosis is rare in patients without overt signs of the disease. Two patients are presented to alert physicians to the value of early scalene node biopsy when sarcoidosis could be the cause of marked disturbances in cardiac conduction. The first patient, aged 29 years, had first, second, and third degree atrioventricular block and intermittent left and ...

The first ten cycles following cessation of atrial pacing were evaluated in 44 control subjects (mean age 52.9 +/- 14.88 yr) and 39 patients (mean age 62.9 +/- 15.41 yr) suspected of having sinus node dysfunction (SND). The maximal cycle length for each postpacing cycle following several pacing periods in each control subject was determined, and was normalized by dividing it by the subject's me...

Because of the frequent occurrence of significant dysrhythmias after Mustard's operation for transposition of the great arteries, electrophysiological studies were performed in i6 patients during postoperative cardiac catheterization. Intracavitary electricalpotentials were recordedfrom the conduction system in all i6patients. In 9 of these patients, the stability of the atrioventricular conduc...

We report a case of a 7-year-old girl with atriofascicular Mahaim (AFM) pathway concomitant with Ebstein's anomaly. The QRS wave showed left bundle branch block pattern on electrocardiogram. Holter electrocardiogram showed prolongation of the PR interval and QRS morphological change during sinus tachycardia. An electrophysiological study demonstrated that the distal His potential appeared earli...

The effects of phentolamine, 0-3 mg/min given intravenously for 15 minutes, on His bundle electrograms were studied in 11 patients with heart disease. Recordings were made at varied heart rates, using atrial pacing. Phentolamine significantly reduced the AH interval in every patient but it had no effect on the HV interval. Functional and effective refractory periods were measured with the use o...

Cystic tumours of the atrioventricular node (sometimes called ‘‘benign mesotheliomas of the atrioventricular node’’) are rare lesions associated with sudden cardiac death. 2 A recent case provided several informative points regarding the nature of this lesion and best practice methodology within the coroner’s necropsy. A 31 year old man, training for a marathon, collapsed and died suddenly with...

Paroxysmal supraventricular tachycardia most commonly arises from reentry within the atrioventricular (AV) node. Although ablation of the His bundle has gained popularity for treating patients with AV node reentrant tachycardia refractory to medical therapy, undesirable sequelae include complete heart block and the necessity for a permanent pacemaker. To obviate this limitation, we have develop...

Ultrastructure of the A-V node was studied in two human hearts. Fine details of intranodal cellular organization were then resynthesized on the basis of light microscopic examinations of over 250 human hearts. There are four different types of cells and no anatomic syncytium in the human A-V node: (1) a simple rounded cell identical to P cells of the sinus node, (2) a slender transitional cell ...

Few patients with corrected transposition of the great arteries survive past 50 years of age because of the association with congenital defects, development of total atrioventricular block, and right ventricular dysfunction. We report the case of a male patient with dextrocardia in situs solitus and corrected transposition of the great arteries associated with a wide atrial septal defect and se...