Incidental extracardiac findings in cardiac computed tomography performed before radiofrequency ablation of atrial fibrillation

BACKGROUND

Radiofrequency ablation has became a validated therapeutic technique for symptomatic drug refractory atrial fibrillation (AF). Cardiac computed tomography (CT) is used to evaluate left atrial (LA) anatomy in order to improve AF ablation. The analysis of noncardiac structures during cardiac CT may identify clinically significant incidental findings (IFs). The objective of this study was to determine the prevalence of IF in patients undergoing AF catheter ablation.

METHODS

Between February 2008 and March 2010, all patients planned for a first procedure of AF or LA tachycardia (LAT) ablation underwent a cardiac CT scan and were retrospectively included in this study. Extracardiac IFs were considered to be present if an abnormality was identified without previous clinical suspicion or known disease.

RESULTS

Two hundred and fifty patients (55.2 ± 9.6 years of age, 82.4% men) were enrolled (133 paroxysmal, 43 persistent, 58 permanent AF, and 16 LAT). Fifty-eight patients (23.2%) had a total of 76 IFs. Patients with IF were significantly older (59.5 ± 8.2 vs 53.8 ± 9.7 years old, P < 0.001). No relationship existed between the type of arrhythmia and IF existence. The majority of IFs were pulmonary (50%), with 15.8% of pulmonary emphysema. Two cases of lung cancer and of pulmonary fibrosis, 15 mediastinal adenopathies, and three congenital coronary arteries anomalies were found.

CONCLUSIONS

Cardiac CT scan is a useful tool to evaluate LA morphology before AF ablation. However, as a considerable prevalence of IF was found in our study, extracardiac structures should be routinely analyzed to detect unknown conditions, which could require specific management.

Organ dysfunction and muscular disability in myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder characterized by muscle weakness and multiple organ impairment, especially the eyes, lung, and heart. We conducted the current study to analyze the prevalence and intercorrelation among these disorders and their respective relationships with muscular disability. We assessed medical history, anthropometric data, lung volumes, arterial and venous blood samples, surface 12-lead electrocardiogram, echocardiography, ophthalmologic examination, and muscular impairment rating scale (MIRS) in 106 patients (48 male and 58 female) with DM1, aged 43.7 ± 12.8 years. Obesity, hypertriglyceridemia, and diabetes were found in respectively 25.6%, 47.6%, and 17.1% of patients. Disabling cataract was found in 43.4%, and was independently predicted by age and MIRS. Restrictive lung disease was noted in 34%, and was predicted by MIRS, CTG repeat expansion, and body mass index. Conduction disorders were found in 30.2% of patients and were predicted by left ventricular ejection fraction, MIRS, and CTG repeat expansion.We found significant relationships between cataract, restrictive lung disease, and conduction disorders: patients with cataract and those with conduction disorders exhibited more severe restrictive lung disease than the other patients. Conversely, the relative risk of restrictive lung disease was 2.42 (1% confidence interval [CI], 1.06-5.51) in patients with cataract and 2.54 (1% CI, 1.26-5.07) in patients with conduction disorders. Multivariate analysis revealed that MIRS was the only independent predictor for conduction disorders and restrictive lung disease. MIRS ≥3 and MIRS ≥4 were the best simple cutoff values to predict, respectively, lung and cardiac involvements.To conclude, muscular disability, ophthalmologic, and cardiac and pulmonary involvement are strongly correlated. Particular attention should be given to these entities in patients with distal or proximal muscular weakness.

[Accessory pathway ablation in children: indications and results]

INTRODUCTION

Radiofrequency ablation of accessory pathways (AP) has become a first-line treatment, except in young children where the indications are discussed because of radiation risks and complications of catheterization. The purpose of the study was to evaluate the indications and results of radiofrequency AP ablation in children and teenagers.

METHODS

Electrophysiological study (EPS) was performed in 145 patients aged from 5 to 18 years (13.5±3) with a preexcitation syndrome (PS).

RESULTS

AP ablation was indicated in 66 children (group 1); others represent the group I. Group I was older and less frequently asymptomatic. All children with a spontaneous malignant form had an ablation. Group 1 has a faster conduction through the AP than group 2. The induction of reentrant tachycardia (RT), atrial fibrillation and the presence of a malignant form is more common in group 1. Failures or reappearances of WPW after ablation were frequent (20, 26%) related to a younger age (15±3 vs 17±4) (<0.05). In group 2, one 18-year-old teenager with untreated RT died before ablation. Asymptomatic children are well with disappearance of PS in two. Medically treated symptomatic children are well.

CONCLUSION

If spontaneous malignant forms, symptoms with drugs or practice of competitive sport are indications of AP ablation, it is recommended to wait for adolescence in other children.

Ventricular tachycardia without apparent heart disease: long-term follow-up

The purpose of the study was to evaluate the long-term prognosis of ventricular tachycardia (VT) in patients without structural heart disease (HD).

METHODS

Holter monitoring, exercise test, echocardiography, right angiography, coronary angiography, and electrophysiologic study were performed in 810 patients with VT.

RESULTS

Eighty patients (mean age, 45 ± 17 years) had no apparent HD. VT was reproduced at electrophysiologic study in 62 patients. Mean follow-up was 9.7 ± 7 years. Initially, 91% were treated with drugs. Defibrillator was implanted in 4, including 2 for arrhythmogenic right ventricular cardiomyopathy diagnosed later. VT ablation was performed in 3 patients. Three patients older than 70 years died of nonarrhythmic cause. Other patients are alive without antiarrhythmic drug treatment in 50%. Three developed a dilated cardiomyopathy; and 2, atrial fibrillation.

CONCLUSIONS

Invasive treatment was rarely required in patients with VT without HD. The prognosis was only dependent on the age and the pattern of electrocardiogram in VT.

Pharmacological testing in the diagnosis of arrhythmias

Pharmacological testing has several indications in the diagnosis of arrhythmia. It is used for the diagnosis of bradycardia-related syncope either during non invasive tests as adenosine triphosphate (ATP) for the diagnosis of vasovagal syncope, but also for the diagnosis of sick sinus syndrome or isoproterenol infusion during the head up tilt test to induce a vasovagal syncope or during electrophysiological study to look for infrahisian AV block or organic sick sinus syndrome after injection of Ajmaline or to know if sick sinus syndrome or suprahisian AV block are reversible after atropine and are vagal-related. It is used for the diagnosis of supraventricular and ventricular tachycardia; isoproterenol is largely used generally during electrophysiological study. The infusion of isoproterenol is required in exercise-related arrhythmias, in arrhythmogenic right ventricular cardiomyopathy, in idiopathic ventricular tachycardia and in idiopathic dilated cardiomyopathy. ATP can be used to induce a vagal-related atrial fibrillation and may help to differentiate a reentry through accessory pathway or AV nodal re-entrant tachycardia. It is used for the detection and the evaluation of prognosis of some diseases at risk of sudden death. Isoproterenol infusion is required in the preexcitation syndrome to look for the shortening of accessory refractory period. Ajmaline or flecaïnide injection is mandatory in the family of a patient with a Brugada syndrome to detect the disease.

[Which therapy for which patient? In daily practice]

Although the important progress in the curative treatment of atrial fibrillation, the indications of the regularisation of the first episode and of the preventive treatment remain difficult. Without real proofs on the interest of maintain in sinus rhythm, the indications depend on the age of the patient, the clinical tolerance and the objective impact on left ventricular ejection fraction.