Normal Electrophysiological Findings in a Patient with Symptomatic Intermittent Advanced Atrioventricular Block

This report describes an otherwise healthy young woman who presented with syncope during episodes of advanced atriovenlricular (A V) block. The His bundle recordings during normal sinus rhythm and atrial and ventricular pacing were normal. Carotid sinus massage produced no abnormality. Subsequently, (he patient received a permanent pacemaker and has been free of symptoms. In termittent advanced A V block has been observed on follow-up electrocardiograms. This unique case demonstrates a potential limitation of routine electrophysiologic investigation.     

Unexpected Coexistence of Supraventricular and Ventricular Tachycardia in Patients with Syncope

The incidence of multiple, inducible sustained arrhythmias during electrophysiologic studies is unknown. We have identified five patients who had several sustained tachycardias, some of which were not previously recognized clinically. Three patients had documented sustained supraventricular tachycardia (one of these also had nonsustained ventricular tachycardia) and two had documented sustained ventricular tachycardia. The clinically documented tachycardia was successfully reproduced in all cases; however, the three cases of supraventricular tachycardia also had sustained ventricular tachycardia initiated, and the two cases of ventricular tachycardia also had sustained supraventricular tachycardia, which had not previously been seen. The underlying common denominators for all five patients were poor left ventricular function due to ischemic heart disease and a history of syncope. In one case of clinical supraventricular tachycardia, the second sustained tachycardia appeared following drug therapy (procainamide), which seemed to convert nonsustained to sustained ventricular tachycardia. In another patient with clinical ventricular tachycardia, the supraventricular tachycardia was also initiated following drug therapy (indecainide). We conclude that: (1) patients with syncope may have multiple arrhythmic etiologies and (2) complete electrophysiologic evaluation, during control studies as well as serial drug studies, are important in the management of these patienls.     

Dual AV Nodal Pathways—Vagal Influences on AV Nodal Conduction

This 52-year-old male presented with syncope and demonstrated two distinct PR intervals on the electrocar-diogram. Electrophysiologic studies showed dual A V nodal path ways. Right-sided carotid sinus massage induced prolonged periods of sinus arrest with no change in AH interval. Left-sided carotid sinus massage produced long AH intervals (slow pathway conduction) with some slowing of sinus rate. Whenever sinus rhythm with slow pathway conduction was observed (long AH) a 20-30 mmHg drop systolic pressure was seen. Following implantation of an AV sequential pacemaker, the patient has been asymptomatic.     

Bronichiloitis obliterms-current concepts

We review current concepts abut the clinical manifestations,diagnosisand treatment of patients with bronchiolitis obliterans (BO)with emphasis on clinical/pathological correlations and recentdevelopments. BO is a relatively rare disease, but its incidenceis probably higher than generally believed and is continuouslyrising, partly because of better recognition, but also becauseof increased exposure to industrial fumes, and its occurrencein lung transplantation. BO is characterized histologicallyby varying degrees of obliteration of the lumen of the respiratorybronchioles by organizing connective tissue often extendinginto the alveoli (‘proliferative’ BO with organizingpneumoni+BOOP) or by more extensive fibrosis and scarring ofthe more proximal, conductive bronchioles (‘constrictive’BO). Diverse clinical conditions have been associated with thedevelopment of BO, notably viral and mycoplasma infection, toxicfume exposure and immune reactions in the setting of a collagenvascular disease, drug reaction or organ transplantation. Theclinical course and features of BO may vary considerably accordingto the aetiology, histological pattern and stage of the disease.The most common presentation is that of a progressive dry coughand dyspnea, associated with diffuse patchy interstitial lunginfiltrates on chest X-ray. In the more advanced cases, lungfunction tests show either restrictive or obstructive defects,depending on the extent of alveolar involvement, and hypoxemiawithout CO₂ retention. The diagnosis is often possible on clinicalgrounds, however, in a seriously ill patient uncertainty shouldbe resolved by tissue diagnosis, preferably by open lung biopsy.Treatment is based on symptomatic therapy. The use of corticosteroidsis controversial, but common. Patients with BOOP are exceptional,in that there may be no underlying condition (‘idiopathic’BOOP or cryptogenic organizing pneumonia—COP), a restrictiveventilatory defect is usual and the response to corticosteroidsoften remarkable.     

The Role of Electrophysiologic Studies in the Management of Patients with Unexplained Syncope

We evaluated the frequency and type of electrophysiologic abnormalities in an unselected population of consecutive patients with unexplained syncope. Fifty patients were entered in the study; all had 24-hour dynamic electrocardiographs (Holter) recordings and underwent complete electrophysiological studies. An abnormal electrophysiologic study was found in 74% of the patients. Sinus node abnormality was observed in 30%, abnormal AV node function in 14%, long HV in 10%, block distal to H during rapid atrial pacing in 6%, paroxysmal supraventricular tachycardia in 12%, ventricular tachycardialfibrillation in 8%, and hypersensitive carotid sinus syndrome in 24%. There was no correlation between Holter and electrophysiologic study findings except for the presence of paroxysmal sustained supraventricular tachycardia. Based on clinical, Holter monitoring, and electrophysiologic findings, 38% were treated by antiarrhythmic drugs, 40% received permanent pacemakers, and. 22% were not treated at all. During follow-up (23 ± 13 months), 9 patients (18%) experienced recurrent syncope or death.