Ablation of atrial fibrillation after the retirement age: considerations on safety and outcome

Background: Although the incidence of atrial fibrillation (AF) progressively increases with age, the vast majority of AF ablation is done in middle-aged patients. We evaluated the feasibility and safety of catheter ablation in patients older than 65years of age with paroxysmal and persistent AF. Methods: Out of a total of 230 consecutive AF ablation procedures, 45 patients were older than 65years of age and underwent 53 procedures. The ablation strategy consisted of wide-area circumferential lines around both ipsilateral pulmonary veins using a three-dimensional mapping system. Results: The mean age was 69 ± 3.5years (35 males). The mean duration for AF was 8.7 ± 6.5years. Thirty-nine had paroxysmal and six persistent AF despite use of 1.38 ± 0.77 antiarrhythmic drugs. All patients had a structurally normal heart. Eleven had systemic hypertension. Mean procedure time was 187 ± 33min. Acute procedural success rate with abolition of all pulmonary vein potentials was achieved in all patients. Pericardial tamponade requiring percutaneous drainage occurred in one (1.9%) patient. There were no cardioembolic events. Among the 43 patients whose clinical outcome was assessed at 6months, 34 (79%) had a significant reduction (>90%) of the total symptomatic AF burden, compared to pre-ablation, with a complete lack of symptomatic AF in 32 (74%) patients. The success rate was higher for patients with paroxysmal versus persistent AF (81 vs. 67%). Six patients (11%) underwent repeat procedures. Conclusions: Catheter ablation is a safe and effective treatment for patients over the age of 65years with symptomatic, drug-refractory AF. Therefore, patients should not be excluded from undergoing AF catheter ablation on the basis of age alon

Arrhythmogenic Right Ventricular Cardiomyopathy and Differential Diagnosis with Diseases Mimicking Its Phenotypes

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease, which is characterized by fibro-fatty replacement of predominantly the right ventricle (RV). The disease can result in ventricular tachyarrhythmias and sudden cardiac death. Our understanding of the pathophysiology and clinical expressivity of ARVC has been continuously evolving. The diagnosis can be challenging due to its variable expressivity, incomplete penetrance and the lack of specific diagnostic criteria. Idiopathic RV outflow tract tachycardia, Brugada Syndrome, athlete's heart, dilated cardiomyopathy, myocarditis, cardiac sarcoidosis, congenital aneurysms and diverticula may mimic clinical phenotypes of ARVC. This review aims to provide an update on the differential diagnosis of ARVC

In vivo heating of pacemaker leads during magnetic resonance imaging

Aims Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium-pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.5 Tesla. Methods and results Pacemaker leads with additional thermocouple wires as temperature sensors were implanted in nine animals. Temperature increases of up to 20°C were measured during MRI of the heart. Significant impedance and minor stimulation threshold changes could be seen. However, pathology and histology could not clearly demonstrate heat-induced damage. Conclusions MRI may produce considerable heating at the lead tip. Changes of pacing parameters due to MRI could be seen in chronic experiments. Potential risk of tissue damage cannot be excluded even though no reproducible alterations at the histological level could be foun

Management of Patients with Atrial Fibrillation: Specific Considerations for the Old Age

Atrial fibrillation (AF) is the commonest of all sustained arrhythmias, and most of the patients seeking medical therapy are in the elderly age group. The management of these patients is particularly difficult due to associated comorbidities. Hypertension, congestive heart failure, left ventricular hypertrophy, and coronary artery disease are often present in the elderly patient population, and therefore, antiarrhythmic drugs often fail due to side effects, proarrhythmia, or poor rhythm control. Recently, radiofrequency catheter ablation has been widely performed as an efficient therapy for recurrent, drug-refractory AF. Nevertheless, patients at old age were underrepresented in prior AF ablation trials, and the current guidelines for catheter ablation of AF recommend a noninvasive approach in the elderly patient group due to the lack of clinical data supporting ablation therapy. However, study results of our group and others are suggesting that catheter ablation is a safe and effective treatment for patients over the age of 65 years with symptomatic, drug-refractory AF, and therefore, patients should not be precluded from catheter ablation only on the basis of age. This paper discusses the pharmacological (rhythm control, rate control, and anticoagulation) and catheter management of AF in the elderly population

Effects of AV delay programming on ventricular resynchronisation: role of radionuclide ventriculography

Purpose: Optimal atrioventricular delay (AVD) setting for cardiac resynchronisation therapy, i.e. biventricular pacing in patients with heart failure, remains a formidable challenge. Thus, the purpose of this study was to evaluate the effects of different AVD on inter- and intra-ventricular resynchronisation using phase histograms of radionuclide ventriculography (RNV). Methods: In 17 consecutive patients (mean age 64 ± 6years), RNV was performed 236 ± 350days after pacemaker implantation for cardiac resynchronisation therapy. Images were acquired during atrial pacing at 80bpm and during biventricular pacing with AVD ranging from 80 to 160ms. Inter-ventricular dyssynchrony was measured by the delay between the mean phase angles of the left and right ventricles. Intra-ventricular dyssynchrony was measured by the standard deviation (SD) of left ventricular phase histograms. Results: Left ventricular (LV) ejection fraction (EF) was inversely correlated to LV dyssynchrony (SD of LV phase histogram, R = −0.82, p < 0.0001). However, the increase in LVEF by biventricular pacing (mean +4.4 ± 4%) showed only modest correlation to the resulting resynchronisation effect (characterised by a −13 ± 8° decrease in LV phase histogram SD, R = −0.38, p < 0.0001). Conclusion: RNV is helpful in optimising pacing parameters for resynchronisation therapy. Varying AVD did not have a major impact on intra- or inter-ventricular resynchronisation. Thus, the benefit of AVD-based LVEF optimisation seems to result from atrioventricular resynchronisatio

Dronedarone reduces arterial thrombus formation

Dronedarone has been associated with a reduced number of first hospitalisation due to acute coronary syndromes. Whether this is only due to the reduction in ventricular heart rate and blood pressure or whether other effects of dronedarone may be involved is currently elusive. This study was designed to investigate the role of dronedarone in arterial thrombus formation. C57Bl/6 mice were treated with dronedarone and arterial thrombosis was investigated using a mouse photochemical injury model. Dronedarone inhibited carotid artery thrombus formation in vivo (P<0.05). Thrombin- and collagen-induced platelet aggregation was impaired in dronedarone-treated mice (P<0.05), and expression of plasminogen activator inhibitor-1 (PAI1), an inhibitor of the fibrinolytic system, was reduced in the arterial wall (P<0.05). In contrast, the level of tissue factor (TF), the main trigger of the coagulation cascade, and that of its physiological inhibitor, TF pathway inhibitor, did not differ. Similarly, coagulation times as measured by prothrombin time and activated partial thromboplastin time were comparable between the two groups. Dronedarone inhibits thrombus formation in vivo through inhibition of platelet aggregation and PAI1 expression. This effect occurs within the range of dronedarone concentrations measured in patients, and may represent a beneficial pleiotropic effect of this dru

Focal atrial tachycardia originating from mirror position of fossa ovalis: A case report

In patients undergoing ablation of focal atrial tachycardia (FAT) arising from the interatrial septum (IAS), mapping of both atria is required. Electroanatomical mapping of the IAS and identification of earliest activation are necessary for assessing arrhythmia origin, leading to an effective radiofrequency ablation. The fossa ovalis (FOv) is an anatomical structure of the right atrium (RA). However, FAT may also arise from the corresponding left IAS. The present case is a FAT originating from the left IAS mirror position of the FOv, corresponding to the earliest activation of the RA. The earliest RA electrogram with double potentials identified in the area of the FOv predicts the mirror position within the left atrium