Catheter ablation and implantable atrial defibrillators in supraventricular cardiac arrhythmias

This study was designed to evaluate drug use and drug costs of treatment of 1112 AIDS patients at the Infectious Diseases Unit at F. Houphou?t Boigny Hospital in Marseilles, France, between January 1, 1990 and December 31, 1994. All drug expenditures directly or indirectly related to AIDS treatment were recorded for both inpatients and outpatients. There were 1952 hospital stays. For each stay baseline characteristics including age, sex risk factors, costs, and duration of hospitalization were noted. Patients were mainly young male drug addicts around thirty years of age. Reason for admission was also noted. The overall number of admissions per year has decreased since 1991 probably due to development of outpatient care. The number of stays per patient per year has decreased since 1993 because of the use of more appropriate therapeutic and prophylactic protocols. The number of drugs used was high increasing from 750 in 1990 to 868 in 1994. Cost of treatment doubled between 1990 and 1994 due to the introduction of many expensive new drugs. Closer analysis showed that the greatest increase in expenditure involved 'antibiotic/antiviral', 'psychiatry/neurology' and 'specialized therapy'. Although not frequently prescribed, costly drugs such as immunoglobulins, hematopoietic growth factors, and parenteral nutrition solutions accounted for a high proportion of total costs. Since AZT, ddI and ddC were used mainly for outpatient treatment, their cost was low in inpatients. Cytomegalovirus-related retinitis, tuberculosis, and multiple infections were cost-intensive complications. The increasing number of cytomegalovirus infections underlines the need for cost evaluation and surveillance of this complication. This study demonstrates that cost of treating AIDS patients is rising due to the use of more and costlier drugs. This finding underlines the need to evaluate and compare new therapeutic modalities in terms of cost effectiveness.     

Catheter ablation in patients with refractory cardiac arrhythmias with radiofrequency techniques

The author suggests a working classification of dermopertorators from analysis of his own designs and devices described in the literature for forming netlike skin grafts in the treatment of patients with large tissue defects. It is shown that the well-known dermoperforators require essential modernization. The most promising model is a device with plane knives whose simple technology allows their production to be organized in Soviet industry.     

Radiofrequency catheter ablation in symptomatic ventricular arrhythmia

Xenopus embryos were exposed to 200 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 5 days from the 2- to 8-cell stage of cleavage to the early larval stage. Larvae that developed generalized edema were collected at 7 days after the end of TCDD exposure for light and electron microscopic studies. Erythrocytes in the peripheral blood of the edematous larvae were examined. Between 0.3 and 33.9% of identifiable erythrocytes of exposed larvae had dilated perinuclear cisternae. Furthermore, some had extremely condensed nuclear chromatin usually coalesced against 1 pole of the nuclear membrane and overall compacted cytoplasm. The erythrocytes showing nuclear condensation were phagocytosed by macrophages. These features are typical of cells undergoing apoptosis. Anemia is 1 symptom of TCDD toxicity in various animal species, including mammals. In this study, we demonstrate that TCDD induces apoptotic cell death in circulating erythrocytes of Xenopus larvae, which may be 1 cause of anemia in this species.     

Catheter ablation of atrioatrial conduction as a cure for atrial arrhythmia after orthotopic heart transplantation

STUDY OBJECTIVES: Little is known about the natural development of snoring, and this survey was conducted to study the development of snoring in men over a 10-year period. DESIGN: Population-based prospective survey. SETTING: The Municipality of Uppsala, Sweden. PARTICIPANTS AND MEASUREMENTS: In 1984, 3,201 randomly selected men aged 30 to 69 years answered a questionnaire on snoring and sleep disturbances. Of the 2,975 survivors in 1994, 2,668 (89.7%) answered a new questionnaire with identical questions to those used at baseline. Questions about smoking habits, alcohol, and physical activity were also added. RESULTS: Habitual snoring was reported by 393 men (15.0%) in 1984 and by 529 (20.4%) 10 years later. In both 1984 and 1994, the prevalence of snoring increased until age 50 to 60 years and then decreased. Risk factors for being a habitual snorer at the follow-up were investigated using multiple logistic regression with adjustments for previous snoring status, age, body mass index (BMI), weight gain, smoking habits, and physical activity. In men aged 30 to 49 years at baseline, the predictors of habitual snoring at the follow-up, in addition to previous snoring status, were as follows: persistent smoking (adjusted odds ratio, 95% confidence interval) (1.4, 1.1 to 1.9), BMI 1984 (1.1, 1.02 to 1.1/kg/m2) and weight gain (1.1, 1.03 to 1.2/kg/m2). Among men aged 50 to 69 years, after adjustments for previous snoring status and age, weight gain was the only significant risk factor for developing habitual snoring (1.2, 1.05 to 1.4/kg/m2). CONCLUSIONS: In men, the prevalence of snoring increases up to the age of 50 to 60 years and is then followed by a decrease. Weight gain is a risk factor for snoring in all age groups, while smoking is mainly associated with snoring in men <60 years of age.     

Radiofrequency ablation in the therapy of supraventricular and ventricular arrhythmias

We summarize our experience with RF-ablation in 70 patients with symptomatic tachycardia (38 females and 32 males, age 25-73 years). 19 patients with AV reentry tachycardia in WPW-syndrome, 28 patients with node reentry tachycardia (AVNRT), 10 patients with ventricular tachycardia, 9 patients with atrial fibrillation and 4 patients with atrial flutter were treated. The primary success rate in the whole patient group is 87% and the longterm success rate (up to 1 year) 81%. RF-ablation of tachycardia is a highly effective therapy. The patients are free of symptoms and need no further medication. In patients with AVNRT in WPW-syndrome and ventricular tachycardia (structurally normal heart), RF-ablation is the therapy of choice. 32/70 patients were treated on an outpatient basis.     

Drug therapy of cardiac arrhythmias 199

Current antiarrhythmic drug therapy is employed in strict compliance with the proper indication, which is itself limited by the side effects of the available drugs, and modified by the increasing success of such non-drug options as electrical ablation and implantable cardioverters/defibrillators. Drug treatment is restricted to 3 major indications, regular paroxysmal supraventricular tachycardias, atrial flutter and fibrillation, and ventricular tachycardias. Class IA and IC agents are used only to treat supraventricular and ventricular arrhythmias with no structural heart disease. Class III drugs, e.g. sotalol and in particular amiodarone are used preferentially to treat the pre-damaged heart, in particular left-ventricular functional impairment and in coronary heart disease in consideration of their side effects. In the case of the most common treatment-requiring arrhythmia-atrial fibrillation-anticoagulation alone may be indicated. For the prevention of sudden death, beta-blockers continue to be the drugs of first choice.     

Catheter ablation for atrial flutter and fibrillation. An effective alternative to medical therapy

Atrial flutter and atrial fibrillation are common arrhythmias that can be difficult to manage clinically. In many patients, these conditions are refractory to pharmacologic therapy because of drug failure or intolerance. Radiofrequency catheter ablation may be a reasonable alternative in patients with typical atrial flutter. The procedure has a high initial success rate and a low complication rate. However, recurrence after ablation is common, and a second treatment session may be needed. In selected patients with atrial fibrillation, radiofrequency ablation can be useful for rate control. However, its use in curing chronic fibrillation is still experimental. The procedure involves insertion of a pacemaker, anticoagulation therapy is still needed in most patients, and the need for antiarrhythmic medication may not be obviated.     

Effects of a lipoxygenase inhibitor on digoxin-induced cardiac arrhythmias in the isolated perfused guinea-pig heart

1. The effects of a lipoxygenase inhibitor, BW A4C, on digoxin-induced arrhythmias and cardiac dynamics (contractile force, perfusion pressure, heart rate) were investigated in Langendorff-perfused isolated guinea-pig hearts. In the control group, arrhythmias were induced by 25 micrograms/ml digoxin at a perfusion rate of 0.5 ml/min. In the treated groups, BW A4C (1 and 0.3 microM) perfused continuously from 15 min prior to digoxin until cardiac arrest occurred. Digoxin exposure (microgram/g wet weight of heart) for the occurrence of arrhythmias and cardiac arrest were the parameters evaluated to assess cardiotoxicity. 2. Digoxin caused a marked increase in leukotriene B4 release in the coronary effluent, and was collected during tachyarrhythmias. BW A4C markedly inhibited the digoxin-induced elevation of LTB4. 3. BW A4C (1 and 0.3 microM) did not prevent the onset of ventricular fibrillation and ventricular tachycardia despite a slight delay in the occurrence of ventricular fibrillation and cardiac arrest at the 0.3 microM concentration. 4. Contractile force increased significantly after digoxin infusion which was concomitant with the time of onset of arrhythmias. In the presence of BW A4C, the contractile force increased, but not significantly. Perfusion pressure increased initially after digoxin infusion in the absence and the presence of BW A4C, but not significantly. 5. These findings show that the lipoxygenase inhibitor lacked any protective action on digoxin-induced arrhythmias despite its effective suppression of digoxin-induced elevation of LTB4 in coronary effluent.     

Perioperative cardiac arrhythmias in digitalized patients with ischemic heart disease (author's transl)

The purpose of this study was to establish the incidence of pre-operative digitalization by intravenous digoxin on cardiac arrhythmias in 24 patients with ischemic heart disease who underwent abdominal surgery. Ambulatory electrocardiographic monitoring was performed for 12 hours before digitalization, for 12 hours during digitalization (before surgery), for the whole period of anesthesia. General anesthesia used thiopentone, phenoperidine, pancuronium and suxamethonium for endotracheal intubation. No more premature ventricular (PVC) and auricular contractions were detected after digitalization and during anesthesia and surgery. But PVC with begeminism or severe bradycardia were recorded in two patients and episodes of "torsades de pointes" occurred in two other patients during endotracheal intubation. "Torsades de pointes" have never been reported after suxamethonium and endotracheal intubation in digitalized patients. Digitalization, ischemic heart disease, cardiac effects of suxamethonium might be factors of the onset of these first reported "torsades de pointes". In conclusion, after a pre-operative digitalization in the coronary patients the frequency of arrhythmias is not exaggerated during the pre- or per-operative period except during induction and intubation. As the role of suxamethonium seems to be important as a trigger for severe arrhythmias endotracheal intubation in digitalized coronary patients should be performed without suxamethonium.     

Cardiac arrhythmias in sleep apnea. Increased cardiovascular risk caused by nocturnal arrhythmia?

In sleep-disordered breathing (SDB), the greatest clinical relevance attaches to obstructive sleep apnea on account of its high prevalence and its concomitance with diseases of the cardiovascular system. The high mortality rate of untreated patients is believed to be due to the consequences of these latter diseases. Thus, for example, in addition to systemic arterial hypertension, elevated rates of such disorders as pulmonary hypertension, right heart insufficiency, coronary heart disease, myocardial infarction and stroke are also found. Up until quite recently bradycardic and tachycardic arrhythmias occurring during sleep have been held responsible of the increased mortality rate of these patients. Till the mid-eighties the prevalence of bradycardic arrhythmias was reported to be more than 30%. However, the importance of cardiac arrhythmias has been overestimated, as is supported in particular by current studies on large non-selected samples showing a much lower prevalence of apnea-related arrhythmias. In the differential diagnosis, however, consideration must be given to SDB in patients with nocturnal arrhythmias and heart rate variations.     

Effects on cardiac performance of atrioventricular node catheter ablation using radiofrequency current for drug-refractory atrial arrhythmias

Patients with atrial fibrillation or atrial flutter (AF) are candidates for radiofrequency (RF) catheter ablation of the atrioventricular (AV) node with the aim being to control heart rate. As patients with AF can have markedly impaired ventricular function, information concerning the hemodynamic effects of AV node ablation using RF current would be valuable. Fourteen consecutive patients (mean age 65 +/- 3 years) with drug-resistant AF underwent AV node catheter ablation with RF current and had permanent pacemaker implantation. The mean left ventricular ejection fraction (EF) by two-dimensional echocardiography immediately before ablation was 42 +/- 3% (range 14%-54%) and their mean exercise time was 4.4 +/- 0.4 minutes. Complete AV block was achieved in all 14 patients with 6 +/- 2 RF applications (range 1-18). There was no evidence of any acute cardiodepressant effect associated with delivery of RF current, and EF 3 days after ablation was 44 +/- 4%. By 6 weeks after ablation, the left ventricular EF was significantly improved compared to baseline (47 +/- 4% postablation vs 42 +/- 3% preablation; P < 0.05), and this modest increase in EF was accompanied by an improvement in exercise time (5.4 +/- 0.4 min). In conclusion, delivery of RF current for AV node catheter ablation in patients with AF and reduced ventricular function is not associated with any acute cardiodepressant effect. On the contrary, improved control of rapid heart rate following successful AV node ablation is associated with a modest and progressive improvement in cardiac performance.     

Recognition and management of childhood cardiac arrhythmias

Axonal connections between the amygdala and the hypothalamic paraventricular nucleus were examined by combined anterograde-retrograde tract tracing. Iontophoretic injections of the retrograde tracer Fluorogold were placed in the paraventricular nucleus, and the anterograde tracer PHA-L in the ipsilateral central or medial amygdaloid nuclei. Single and double-label immunohistochemistry were used to detect tracers. Single label anterograde and retrograde tracing suggest limited evidence for direct connections between the central or medial amygdala and the paraventricular nucleus. In general, scattered PHA-L-positive terminals were seen in autonomic subdivisions of the paraventricular nucleus (lateral parvocellular, dorsal parvocellular and ventral medial parvocellular subnuclei) following central or medial amygdaloid nucleus injection. Double-label studies indicate that central and medial amygdaloid nucleus efferents contact paraventricular nucleus-projecting cells in several forebrain nuclei. In the case of central nucleus injections, PHA-L positive fibers occasionally contacted Fluorogold-labeled neurons in the anteromedial, ventromedial and preoptic subnuclei of the bed nucleus of the stria terminalis. Overall, such contacts were quite rare, and did not occur in the bed nucleus of the stria terminalis regions showing greatest innervation by the central amygdaloid nucleus. In contrast, medial amygdala injections resulted in a significantly greater overlap of PHA-L labeling and Fluorogold-labeled neurons, with axosomatic appositions observed in medial divisions of the bed nucleus of the stria terminalis, anterior hypothalamic area and preoptic area. The results provide anatomical evidence that a substantial proportion of amygdaloid connections with hypophysiotrophic paraventricular nucleus neurons are likely multisynaptic, relaying in different subregions of the bed nucleus of the stria terminalis and hypothalamus.     

Glucagon therapy in the treatment of symptomatic bradycardia

Symptomatic bradycardia is commonly seen in the emergency department. Effective drug therapy for this clinical scenario is limited. Although glucagon has been used in no clinical trial in this setting, its cardiac activity may prove useful, particularly in the setting of beta-adrenergic blockade. We report a case series comprising three patients taking maintenance beta-blocker therapy who presented to the ED with symptomatic bradycardia and hypotension and in whom glucagon therapy obviated the need for further treatment. Further study is warranted to evaluate and define the role of glucagon in the treatment of symptomatic bradycardia.