Safety of transient elastography in patients with implanted cardiac rhythm devices

BackgroundAt present the use of transient elastography (TE) in patients with pacemaker (PM) or implantable cardioverter defibrillator (ICD) devices is not recommended, since the safety due to the electromagnet embarked in the vibrator for producing the shearwave has not been evaluated. However, no adverse events of sonographic examinations in this patient group have been reported.AimsThe aim of the present study was to evaluate the safety of TE in patients with PM or ICD.MethodsIn a prospective study we evaluated safety and function of such devices during TE. In 17 patients with PM and 17 patients with ICD, the function of the device was checked prior to and after TE examination.ResultsIn none of the 34 patients changes in stimulation thresholds, electrode impedance and sensing were detected.ConclusionOur findings support the assumption that the potential harm of TE in patients with PM and ICD is rare.     

History of cardiac rhythm disorders

The history of cardiac rhythm disorders including antiarrhythmic drugs and electrotherapeutical tools is long and fascinating. In the beginning, there was not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. Thus, like any other field of medicine, the study of arrhythmias has a distinctive past. Our current level of knowledge is not the result of a straight, linear progression any more than there is a static, established, monolithic body of thought dominating this field. Instead, our knowledge of arrhythmias today is the result of many competitive, sometimes serendipitous, scientific realizations, of which a few proved useful enough to pursue and eventually led to real advancements. Looking at the worldwide development of rhythmology it can be said that considerable contributions came from Germany in the last few centuries. Arrhythmology--past, present and future--includes clearly German investigators as pioneers of the field. The growing clinical importance of electric cardiac stimulation has been recognized and renewed as Zoll in 1952 described a successful resuscitation in cardiac standstill by external stimulation. The concept of a fully automatic implantable cardioverter-defibrillator system for recognition and treatment of ventricular flutter/fibrillation was first suggested in 1970. The first implantation of the device in a human being was performed in February 1980. By early 1997, 17 years after the first human implantation more than 100,000 ICD systems had been implanted worldwide. Further developments concern new pharmacological compounds, modern cardioverter-defibrillators, radiofrequency ablation, particularly pulmonary vein ablation in atrial fibrillation, innovative pacemakers including preventive pacing techniques, probably laser therapy and perhaps the automatic implantable pharmacological defibrillator. The advances in the field of therapeutic application of pharmacologic and electrical means as well as alternative methods will continue as rapidly as before in order to give us further significant aid in taking care of the patient.     

Management of disorders of cardiac rhythm

Dr. Gold: The treatment of disorders of cardiac rhythm was explored in this conference. This was a very large undertaking. There are several types of disorders of rhythm; there are various devices for distinguishing one from another. It is important to do so for there are significant differences in the treatment of each, and the most successful results depend on the use of measures specifically suited to the particular problem. A special conference could be profitably devoted to any one disorder of rhythm.There has been no attempt to exhaust the subject, but many points of practical interest have been brought out in the account of experience and opinion by the various participants. Many of the details cannot be satisfactorily summarized without repeating the conference. The following disorders of rhythm received attention: premature contractions, auricular and nodal tachycardia, auricular flutter, auricular fibrillation, ventricular tachycardia and heart block. There was some discussion of the management of congestive failure in the course of a paroxysm of abnormal rhythm and the problem of ectopic rhythms occurring in the hyperthyroid state. It was pointed out that three distinct problems prevail in cases of disordered rhythm, namely, those in whom the disordered rhythm is a chronic phenomenon and is to be allowed to continue, those in whom an acute paroxysm needs to be terminated and those in whom the problem is essentially one of preventing recurrences. Means for differential diagnosis were described, namely, certain clinical features, the electrocardiogram, carotid sinus pressure and various devices exerting similar effects.The application of several drugs was discussed in some detail, such as quinidine, digitalis, magnesium sulfate, procaine, mecholyl, ipecac, ephedrine, morphine and other sedatives. In a patient with a paroxysm of rapid heart action which does not appear to be damaging the circulation unduly, there are some who prefer to give a dose of morphine to make the patient more comfortable and let the problem rest until the abnormal rhythm ceases spontaneously. Digitalis appears to be the drug of choice for the paroxysm of auricular and nodal tachycardia. While mecholyl is very effective, it is so apt to produce disturbing symptoms that it is best to keep it in reserve for use when other measures fail. Quinidine is the standard remedy for an attack of ventricular tachycardia; and when for one reason or another it proves inadequate, an intravenous injection of magnesium sulfate is sometimes effective. There are risks involved in the use of all these drugs to abolish a paroxysm of abnormal rhythm, and technics were described for reducing the hazards to a minimum.Attention was called to the fact that there are many situations in which a differential diagnosis among the disorders of rhythm is difficult or impossible to make, but that even under those conditions, a specific form of therapy is still available; for quinidine is highly effective against five of the more common disorders of rhythm: premature contractions, paroxysmal auricular tachycardia, auricular flutter, auricular fibrillation and ventricular tachycardia. Strong emphasis was placed, however, on the desirability for making every effort to establish the precise mechanism before treatment is started, for only then is the most rational and effective plan of therapy possible.Finally, the point was made that one should always bear in mind the underlying state of the heart in which a rapid ectopic rhythm has suddenly appeared. The abnormal rhythm is a dramatic event and may engage the attention of the examiner to the exclusion of other factors of far greater importance than the abnormal rhythm, such as Graves' disease or an acute coronary thrombosis.     

Management of infections involving implanted cardiac electrophysiologic devices

Indications for cardiac electrophysiologic device implantation have expanded, and the target demographic has widened. Unfortunately, these changes have been accompanied by an increase in cardiac device-associated infections out of proportion to the increase in implantation rate. Diagnosing a cardiac device infection may be challenging because of the spectrum of clinical manifestations, ranging from isolated generator pocket pain to frank sepsis with clear evidence of endocarditis. Any component of the device may be involved, but the cornerstone of therapy remains extraction of the device and its leads along with appropriate antibiotic treatment. Given the inherent risks of lead extraction, making the correct diagnosis is paramount. This review outlines the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of cardiac device infections.     

Angiotensin receptor blockers and cardiac rhythm disorders

Angiotension Receptor Blockers (ARB) are able to prevent the occurrence of atrial fibrillation (AF) through various mechanisms among them: neurhumoral antagonism and hemodynamic control. This occurs during arterial hypertension and chronic heart failure both diseases known to be associated with left atrial dysfunction. In the CHARM program, candesartan reduced by 20% the incidence of AF and thus also mortality and the incidence of hospitalisation for heart failure related to AF This beneficial effect is also observed with ACE inhibitors but is more important and potentated by ARB. In the Val-Heft study, valsartan on the top of standard treatment including ACE inhibitors, significantly lowered the cases of AF In hypertensive patients, ARB are more powerful than ACE inhibitors for the prevention of AF In the LIFE study, patients in the losartan arm had 33% less AF than patients from the other arm, despite treatment with atenolol and similar blood pressure reduction. Moreover ARB beside their specific effects are also able to increase efficiency of anti-arrhythmic agent; since after cardioversion patients treated with amiodarone plus irbesartan had a lower rate of recurrence of atrial fibrillation than patients treated with amiodarone alone. Finally ARB may reduce the risk of sudden death by ventricular arrhythmias in patients with diabetes mellitus.