Alcoholic and Non-alcoholic Liver Disease in Relation to Alcohol Consumption in Scotland, 1978–84.

A common strategy in epidemiological studies linking alcohol consumption in the general population with liver cirrhosis mortality is to use non-specific cirrhosis mortality rates in which alcoholic and non-alcoholic causes of death are not distinguished. Evidence is presented from Scottish mortality data for 1979 to 1984 that the two forms of cirrhosis have quite different epidemiological profiles. Similar findings emerge from morbidity data. The two forms of disease should be distinguished in future studies in which liver cirrhosis is used as a proxy for consumption, despite the manifest shortcomings of currently available data.     

The Value of Transesophageal Atrial Pacing in Predicting the Efficacy of Antiarrhythmic Drugs in Patients with Paroxysmal Narrow QRS Complex Tachycardia

Transesophageal atrial pacing (TAP) is used in the diagnosis and treatment of paroxysmal narrow QRS complex tachycardia (NQT). The aim of this study was to assess the value of this technique in predicting the efficacy of antiarrhythmic therapy. The study group consisted of 30 consecutive patients with spontaneous NQT whose clinical tachycardia was inducible by TAP. Baseline TAP was performed off all antiarrhythmic medication and repeated during oral antiarrhythmic drug therapy. The pacing protocol consisted of three stages: a single extrastimulus introduced at progressively shorter coupling intervals during sinus rhythm, pacing at incremental rates to the point of second-degree AV block, and bursts of rapid pacing. On repeat stimulation while on oral antiarrhythmic therapy (37 pacing studies) NQT was still inducible in 12 cases. During the follow-up period ten patients developed a recurrence of NQT:nine cases out of 12 (75%), in whom NQT was inducible while on antiarrhythmic therapy, and one case out of 25 (4%), in whom NQT was not inducible (P less than 0.001). The sensitivity of TAP in predicting the outcome of the patients with NQT was 90%, and the specificity 89%. The negative predictive value of TAP (prediction of no recurrence of NQT) was 96%, and the positive predictive value (prediction of recurrence of NQT) was 75%. We conclude that TAP is a simple and accurate method for predicting the efficacy of antiarrhythmic treatment in patients with NQT.     

True Incidence of Pacemaker Syndrome

HELDMAN, D., ET AL.: True Incidence of Pacemaker Syndrome. Although the purported incidence of pacemaker syndrome according to the literature is only 5%–15%, this is based on a series of patients with VVI pacing. Increasing numbers of studies are being reported in which patients prefer the dual chamber mode despite little benefit being demonstrated on objective testing, suggesting that pacemaker syndrome may be more common than is generally reported. This study was designed to evaluate the reported symptoms in a series of patients programmed to both the VVI and one or more dual chamber modes. Forty unselected patients with dual chamber pacemakers were entered into a blind, randomized trial comparing the symptoms associated with VVI pacing to those associated with dual chamber pacing. Patients were randomized to either WI or dual chamber pacing. At the end of 1 week, questionnaires rating 16 different symptoms were completed. Blood pressure, LV function, presence of ventriculoatrial conduction, and ability to override the pacemaker were evaluated. The pacemaker was then programmed to the other mode. Overall, 12 of 16 symptoms were significantly worse in the VVI as compared to dual chamber mode. The most highly significant (p < 0.005) were shortness of breath, dizziness, fatigue, pulsations in the neck or abdomen, cough, and apprehension. Pacemaker syndrome was clinically recognized in 83% of patients paced in the WI mode with 65% of patients experiencing moderate to severe symptoms. There were no readily identified clinical, hemodynamic, or electrophysiological parameters that predicted which patients would develop pacemaker syndrome. Thus, when patients have an opportunity to experience both pacing modes in close proximity to one another, there is a high incidence of pacemaker syndrome in the VVI mode.     

Termination of Macro-Reentrant Tachycardia by a Single Extrastimulus Delivered During the ''Effective'' Refractory Period: A Computer Modeled ''Case Report''

A computer model of cardiac excitation sequences was used to reproduce atrioventricular (AV) reentrant tachycardia (AVRT) and its termination by a single 'on-circuit' extrastimulus. The model simulated activation waves revolving along a one-dimensional circular pathway, the portions of which represented the atrial, AV nodal, His-Purkinje, ventricular, and accessory pathway sections of the tachycardia circuit. The modeled pathway was composed of 289 elements. The model distinguished only the depolarised and resting states of constituent elements, but introduced differential refractoriness and conduction velocity for each element. These values approximated the natural situation established in a patient suffering from AVRT associated with the right bundle branch block. The results of the study suggest that: (A) the usual impression of a regular recovery wave and of a regular excitable window moving uniformly along the macro-reentrant circular path is incorrect; (B) during the tachycardia, islands of repolarized cells appear which are surrounded by tissue that is still refractory; (C) an extrastimulus which captures the island of early repolarized tissue may cause an excitation restricted to a small part of the myocardium but the local refractoriness following such an extrastimulus may be sufficient to terminate the tachycardia.     

Sudden Death Mortality in Implantable Cardioverter Defibrillator Patients

Implanfable Cardioverter defibrillator (ICD) prevention of sudden cardiac death (SCD) is not absolute and our experience was reviewed to determine the frequency and nature of SCO in this population. The incidence and cause of mortality in 56 consecutive patients, who underwent ICD implantation beginning May 1982 with follow-up through May 19, 1990 were analyzed. Twenty-one patients died, 33% of the mortality was due to SCD, and 52% of deaths may be considered arrhythmic. The cumulative 1, 3, and 5 year SCD survivals were 93%, 89%, and 75%. All seven patients dying of SCD presented initially with SCD, all received previous shocks prior to SCD, and two of the seven patients had devices that were probably inactive at the time of death. We conclude that ICDs reduce but by no means eliminate arrhythmic death, particularly in those at highest risk for SCD. Arrhythmic death remained the most common cause of death in this population.     

Obscure Syncope and the Sick Sinus Syndrome

This report describes a 25-year-old vigorous young man who had a history of eight years of near syncope and syncope of unknown etiology. Repeat in-hospital observation and laboratory electrophysiologic functional testing did not elucidate the origin of the symptoms. Prolonged Holter monitoring finally showed that the syncopal attacks were caused by a sick sinus syndrome (SSS). On electrophysiologic study, a concealed rate-dependent unidirectional antegrade accessory A-V pathway (AP) was found to be present. The AP was an incidental finding and was unrelated to the patient's symptoms. The symptomatic SSS may occur in the young as well as in the elderly. Sinoatrial dysfunction may be intermittent and difficult to detect, may cause severe symptoms, and may even be life-threatening. Prior to definitive therapy (such as the permanent implantation of a pacemaker), the importance of relating symptoms to a rhythm disturbance has been stressed. In cases where the cause of the symptoms is not obvious, this is best accomplished by continuous Holter monitoring.