Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

Background: Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed.

Methods And Results: We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures.

Radiofrequency ablation of childhood arrhythmia: observational registry in 125 children.

Background: Radiofrequency ablation (RFA) in children is an increasingly common practice.

Objective: To evaluate, in our institution, the results of RFA in children younger than 15 years.

Methods: A total of 125 children submitted to RFA between May 1991 and May 2010 were analyzed.

Unusual complications of percutaneous epicardial access and epicardial mapping and ablation of cardiac arrhythmias.

Background: Percutaneous epicardial access and mapping/ablation of cardiac arrhythmias are being increasingly performed. Although complications such as pericardial effusion are relatively common, other unusual complications may occur due to the complex anatomic architecture of the heart and surrounding tissues. In this report, we report a series of rare and unusual complications related to percutaneous epicardial procedures.

Left atrial function after ablation for paroxysmal atrial fibrillation.

Radiofrequency ablation of the pulmonary veins has been used to treat patients with paroxysmal atrial fibrillation (AF), and atrial damage after ablation is an issue of concern. To evaluate left atrial function shortly and midterm after ablation, 33 consecutive patients with paroxysmal AF were studied at baseline, 24 hours, and > or =6 months after ablation. Patients in sinus rhythm with normal ventricular function were included in the study.

Effect of local anesthetics with and without vasoconstrictor agent in patients with ventricular arrhythmias.

Background: The routine use of local anesthetics associated to vasoconstrictors for the dental treatment of patients with cardiopathies is still controversial, due to the risk of adverse cardiovascular effects.

Objective: To evaluate and compare the hemodynamic effects of the use of local anesthetics with a non-adrenergic vasoconstrictor in patients with ventricular arrhythmia, when compared to the use of anesthetics without vasoconstrictor.

Methods: A prospective randomized study evaluated 33 patients with positive serology for Chagas' disease and 32 patients with coronary artery disease that presented complex ventricular arrhythmia at Holter monitoring (>10 EV/h and NSVT), of which 21 were females, aged 54.

Functional behavior of patients with conventional pacemakers undergoing cardiac resynchronization.

Background: Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking.

Anatomic relations of the Marshall vein: importance for catheterization of the coronary sinus in ablation procedures.

Aims: Our objective was to study the anatomic relations of the human left atrial oblique vein (Marshall vein), particularly of its ostium opening into the coronary sinus, in order to guide ablation procedures related to that vein.

Methods And Results: The study was carried out in 23 heart-specimens (mean weight 446 +/- 204 g) of individuals whose mean ages were 43 +/- 21 years, 20 males. The coronary sinus was opened longitudinally, exposing the ostium of the tributary veins; the Vieussens valve was looked for, as well as its relationship to the left atrial oblique vein.

Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters.

Objectives: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter ablation.

Methods: Fifty-two consecutive patients underwent RF ablation of cavotricupsid isthmus (CTI) for the treatment of typical atrial flutter, using catheter with closed irrigation system (n=26) or 8 mm-tip catheter (n=26).

Radiofrequency catheter ablation of premature ventricular contractions originating in the right ventricular outflow tract.

Objectives: To evaluate if radiofrequency catheter ablation is an effective procedure for the treatment of right ventricular outflow tract premature ventricular contractions (RVOT-PVC) and ascertain if it results in an improvement of symptoms.

Methods: A prospective study with 30 consecutive patients (mean age 40 +/- 13 years, 25 females), with no apparent structural cardiopathy, with very frequent (mean density of 1,263 +/- 593/h) RVOT-PVC, symptomatic for more than one year (mean = 74 months) and resistant to antiarrhythmic drugs (3 +/- 1.7, including beta-blockers), who underwent radiofrequency catheter ablation.

Ventricular remodeling in right ventricular apical pacing.

Objective: To determine ventricular remodeling (VR) and the role of clinical and functional variables in patients with normal cardiac function who underwent right ventricular apical pacing (RVAP).

Methods: Among the 268 consecutive patients with standard pacemaker due to complete atrioventricular block (CAVB), those with left ventricular ejection fraction (LVEF) < 55% and left ventricular end-diastolic diameter (LVEDD) > 53 mm on Doppler echocardiography were excluded. Ventricular remodeling was defined as echocardiographic changes documented at least six months after implantation, namely, a >10% increase in LVEDD and a > 20% decrease in LVEF.

Syncope in patients with right ventricle outflow tract premature beats and no apparent structural cardiopathy.

Objective: Study the prevalence of neurocardiogenic etiology in patients with unexplained syncope and ventricular premature beats, with right ventricle outflow tract morphology (RVOT) and no apparent structural cardiopathy.

Methods: Ninety patients (66 women, mean age 40.2 +/- 16.

Effectiveness of the maze procedure using cooled-tip radiofrequency ablation in patients with permanent atrial fibrillation and rheumatic mitral valve disease.

Background: Although the Cox-Maze III procedure is effective for treating permanent atrial fibrillation (AF), its high complexity limits its use. The Saline-Irrigated Cooled-tip Radiofrequency Ablation (SICTRA) System is an alternative source of energy used to ablate AF. The aim of this study was to evaluate the effectiveness of the SICTRA for the treatment of permanent AF in patients with rheumatic mitral valve (MV) disease.

Electrocardiogram during tachycardia in patients with anterograde conduction over a Mahaim fiber: old criteria revisited.

Objectives: The aim of this study was to prospectively evaluate the sensitivity, specificity, and positive and negative predictive values of previously described ECG criteria to identify preexcited tachycardia due to decrementally conducting accessory pathways (QRS axis between 0 and -75 degrees , QRS width < or = 0.15 seconds, an R wave in lead I, an rS pattern in lead V(1), RS > 1 QRS transition > V(4), and cycle length between 220 and 450 ms).

Background: Preexcited tachycardia associated with decrementally conducting right-sided accessory pathways usually shows a rather "narrow" QRS complex and can be difficult to differentiate from supraventricular tachycardia (SVT) with left bundle branch block (LBBB) aberrant conduction.

Short atrioventricular Mahaim fibers: observations on their clinical, electrocardiographic, and electrophysiologic profile.

Unlabelled: Short A-V manheim fiber.

Introduction: A short atrioventricular decrementally conducting accessory pathway is an uncommon variant of preexcitation. Available data from small series suggest that their decremental properties might not be caused by A-V nodal-like tissue.

Dual conduction in a Mahaim fiber.

The case of an 8-year-old girl with incessant nonsustained left bundle branch block-like tachycardia refractory to antiarrhythmic drug therapy is reported. Electrophysiologic study revealed the presence of a right-sided accessory atriofascicular pathway. Episodes of nonsustained tachycardia were found to be based upon a dual response in AV conduction over the Mahaim fiber to one P wave.

Surgical treatment of atrial fibrillation through isolation of the left atrial posterior wall in patients with chronic rheumatic mitral valve disease. A randomized study with control group.

Objective: To determine the effectiveness of surgical isolation of the left atrial posterior wall encompassing the ostia of the pulmonary veins for the treatment of atrial fibrillation of rheumatic etiology.

Methods: Prospective and randomized study of patients with rheumatic mitral valve disease, persistent atrial fibrillation for 6 months or longer, age < or = 60 years, and left atrial diameter < or = 65 mm. The patients were randomly distributed into 2 groups as follows: surgical valvular treatment (control group) and surgical valvular treatment associated with isolation of the left atrial posterior wall according to the "cut-and-sew" technique (treated group).

Automaticity in Mahaim fibers.

Introduction: Automatic rhythms associated with Mahaim fibers usually occur during radiofrequency catheter ablation. The incidence and significance of spontaneous automaticity in Mahaim fibers are unknown.

Methods And Results: Spontaneous automatic rhythms were observed in 5 (12.