Eduardo Sosa

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. Methods and Results—Between February 2002 and April 2003, 70 patients with permanent AF and rheumatic MV disease were randomly assigned to undergo a modified Maze III procedure using SICTRA associated with MV surgery (group A) or MV surgery alone (group B). Groups A and B were similar in terms of baseline characteristics. The in-hospital mortality rate was 2.3% (1 death) in group A versus 0% (no deaths) in group B (P>0.99). The additional time required for the left-sided radiofrequency ablation in group A was 14.2±5.1 minutes and for right-sided ablation was 12.3±4.2 minutes. The mean postoperative follow-up periods were 13.8±3.4 and 11.5±7.3 months, respectively, in groups A and B. The overall mid-term survival rate was 95.1% in group A and 92.8% in group B (P>0.99). The cumulative rates of sinus rhythm were 79.4% in group A and 26.9% in group B (P=0.001). Doppler echocardiography documented biatrial transport function in 90.3% of group A patients in sinus rhythm. Conclusions—The SICTRA is effective for treating permanent AF associated with rheumatic MV disease.

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. Methods and Results— Between 2006 and 2011, 334 patients underwent attempts at percutaneous, subxiphoid access for epicardial mapping/ablation at 5 experienced centers. Seven selected complications are highlighted in this case series. Patient 1 had a 1-cm right ventricular pseudoaneurysm after several unsuccessful attempts at epicardial access. This was successfully managed conservatively. Patient 2 had intra-abdominal bleeding related to puncture of the left lobe of the liver during access that required surgical repair. Patient 3 had a subcapsular hepatic hematoma that was probably related to percutaneous access and was successfully managed conservatively. Patient 4 had severe pericardial bleeding followed by ventricular fibrillation, immediately after obtaining percutaneous epicardial access. A lacerated middle cardiac vein was repaired surgically. However, the patient ultimately died of complications. Patient 5 had a history of cardiothoracic surgery and developed a right ventricle-abdominal fistula after multiple attempts at percutaneous access. This was surgically repaired without major sequelae. Patient 6 had cardiac tamponade caused by a lacerated coronary sinus branch during epicardial catheter ablation and required surgical repair. Patient 7 had severe left coronary vasospasm and ventricular fibrillation during catheter manipulation in the pericardium. This complication was successfully managed with intracoronary nitrates. Conclusions— Though generally safe, percutaneous epicardial access and mapping/ablation can result in uncommon complications. Awareness of these rare complications may facilitate early detection and successful management.

Pressure frequency characteristics of the pericardial space and thorax during subxiphoid access for epicardial ventricular tachycardia ablation.

BACKGROUND Nonsurgical subxiphoid pericardial access may be useful in ventricular tachycardia ablation and other electrophysiologic procedures but has a risk of right ventricular puncture. OBJECTIVE The purpose of this study was to identify a signature pressure frequency that would help identify the pericardial space and guide access. METHODS The study consisted of 20 patients (8 women and 12 men; mean age 59.1 +/- 14.2 years; left ventricular ejection fraction 25.2% +/- 12.2%; failed 1.8 +/- 0.5 endocardial ablations; unresponsive to 2.0 +/- 1.0 antiarrhythmic drugs; 6 ischemic cardiomyopathy, 12 nonischemic cardiomyopathy, 2 normal heart; 4 previous sternotomy) undergoing epicardial ventricular tachycardia ablation. After pericardial access was obtained, a 10Fr long sheath was used to record pressure inside the pericardium and pleural space. Pressures were analyzed using a fast Fourier transform to identify dominant frequencies in each chamber. RESULTS Mean pressures in the pleural space and the pericardium were not different (7.7 +/- 1.9 mmHg vs 7.8 +/- 0.9 mmHg, respectively). However, the pericardial space in each patient demonstrated two frequency peaks that correlated with heart rate (1.16 +/- 0.21 Hz) and respiratory rate (0.20 +/- 0.01 Hz), whereas the pleural space in each patient had a single peak correlating with respiratory rate (0.20 +/- 0.01 Hz). CONCLUSION The pericardial space demonstrates a signature pressure frequency that is significantly different from the surrounding space. This difference may make minimally invasive subxiphoid pericardial access safer for nonsurgeons and may have important implications for electrophysiologic procedures.

Atrioesophageal fistula—a dangerous complication of catheter ablation for atrial fibrillation

Atrioesophageal fistula is a rare but potentially fatal complication of radiofrequency catheter ablation for atrial fibrillation. Early recognition of this condition is crucial, and raising awareness could help reduce mortality. Here, Scanavaccaet al. discuss how and why fistulas occur, and suggest ways in which they could be avoided in future.

Electrocardiographic Identification of Mid-Septal Accessory Pathways in Close Proximity to the Atrioventricular Conduction System

In order to identify ECG characteristics of overt midseptal accessory pathways (APs) predictive of close proximity to the AV conduction system we analyzed data from patients who underwent successful RF catheter ablation of a mid‐septal AP, Mean patient age was 31 ± 16 years, and 13 were male. The 40° right anterior oblique view was used to divide the mid‐septal area into 3 zones: 1 (anteriorportion); 2 (intermediate); and 3 (posterior portion). The 12‐lead ECG was analyzed with regard to delta wave polarity and R/S transition in the precordial leads. The findings from patients ablated at zone 3 were compared to those at zones 1 and 2. All patients had a positive delta wave in the leads I, II, aVL, and negative delta wave in the leads III and aVR. The R/S transition occurred in lead V2 in 80% of patients. The delta wave in lead aVF was the only ECG characteristic that correlated with the AP ablation zone. Six of 8 patients ablated at zone 3 had a negative delta wave in lead aVF while 6 out of 7 patients ablated at zone 1 or 2 had a positive or isoelectric delta wave in lead aVF (P = 0.03). A positive or isoelectric delta wave in lead aVF identifies mid‐septal AP in close proximity to the AV conduction system.

Incessant ventricular tachycardia due to spontaneous automaticity in the Purkinje network inducing reversible left ventricular dysfunction

This is a report of reversible left ventricular dysfunction due to incessant automaticity in the Purkinje network. The ideal site for ablation was determined by the presence of a spike, which suggested depolarization of some fascicle of the right bundle-branch of the His–Purkinje system or from an atrio-fascicular Mahaim fibre.

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background—Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results—An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions—Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings.

Evolução clínica de pacientes com síncope neurocardiogênica (SNC) após suspensão da terapia específica

OBJECTIVE To evaluate the outcome of patients with NCS after interruption of pharmacological therapy and to investigate the possible clinical variables predicting recurrence. METHODS Thirty-seven patients (age 31+/-16 years) with refractory recurrent NCS being 19 females where prospectively studied. All patients became asymptomatic and had a negative tilt table test (TT) after pharmacological therapy. The treatment was interrupted and one month later, a new TT with no medication was carried out. The probability free of symptoms recurrence was analyzed according to sex, age, number of syncope episodes previously to the treatment, clinical history time, treatment time, drug free from treatment time and TT result. RESULTS Twenty-two patients (59%) presented recurrence during a mean follow-up of 21+/-19.7 months. The variables related to greater recurrence were number of previous syncope (p=0.0248), positive TT after interruption of the therapy (p=0.0002) and female gender (p=0.0131). CONCLUSIONS Most of the very symptomatic patients with NCS present recurrence after the suppression of a specific therapy. A TT carried out after treatment discontinuation can identify patients with higher risk of recurrence, specially in the first year of follow-up.

Type I atrial flutter radiofrequency ablation. Importance of bidirectional line of block in the inferior vena cava tricuspide annulus isthmus

PURPOSE: To determine the clinical importance of a bi-directional line of block demonstration in the inferior vena cava-tricuspid annulus isthmus as an end-point for radiofrequency (RF) atrial flutter (FL) ablation. METHODS: Forty consecutive patients (51±11 years) with type I FL were divided in 2 groups: GI (30 patients) anatomic, non-electrophysiologic isthmus ablation technique (interruption and non-induction FL criteria); and GII (10 patients) anatomic with electrophysiologic evaluation of bi-directional isthmus conduction. The isthmus activation was analyzed before and after anatomic RF ablation with a cateter exploring each side of the line of block, depending on the conduction evaluation (anterograde or retrograde). RESULTS: FL was interrupted and not reinduced in 26/30 (86.6%) GI patients and in 10 (100%) GII patients (p= 0.5558). During follow-up FL recurred in 30% of the patients in both groups. In GII, 6 patients with bi-directional block remained assymptomatic, whereas 3 patients with unidirectional block presented recurrence (p= 0.012). CONCLUSION: Electrophysiologic demonstration of bi-directional line of block in the isthmus is related to long-term success and should be the criterion for interruption of type I atrial FL RF ablation.PURPOSE To determine the clinical importance of a bi-directional line of block demonstration in the inferior vena cava-tricuspid annulus isthmus as an end-point for radiofrequency (RF) atrial flutter (FL) ablation. METHODS Forty consecutive patients (51 +/- 11 years) with type I FL were divided in 2 groups: GI (30 patients) anatomic, non-electrophysiologic isthmus ablation technique (interruption and non-induction FL criteria); and GII (10 patients) anatomic with electrophysiologic evaluation of bi-directional isthmus conduction. The isthmus activation was analyzed before and after anatomic RF ablation with a cateter exploring each side of the line of block, depending on the conduction evaluation (anterograde or retrograde). RESULTS FL was interrupted and not reinduced in 26/ 30 (86.6%) GI patients and in 10 (100%) GII patients (p = 0.5558). During follow-up FL recurred in 30% of the patients in both groups. In GII, 6 patients with bi-directional block remained assymptomatic, whereas 3 patients with unidirectional block presented recurrence (p = 0.012). CONCLUSION Electrophysiologic demonstration of bidirectional line of block in the isthmus is related to long-term success and should be the criterion for interruption of type I atrial FL RF ablation.

Ablação com RF de arritmia na infância: registro observacional em 125 crianças

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. RESULTS Sixty-seven (53.6%) children were males, aged between 44 days and 15 years (mean 8.6 ± 3.3 years) with median weight of 31 kg. Heart disease was present in 21 (16.8%) patients. The RFA of accessory pathways (AP) was the most common procedure (62 children - 49.6%). The RFA of nodal reentrant tachycardia (NRT) was the second most common arrhythmia in 27 (21.6%), followed by atrial tachycardia (AT) in 16 (12.8%) and ventricular tachycardias (VT) in 8 (6.4%) children. The success criteria were achieved in 86.9%, 96.1%, 80% and 62.5% of patients undergoing RFA of AP, NRT, AT and VT, respectively. Transient AVB occurred during RFA in 4 (3.2%) and LBBB in 7 (5.6%) children. Twenty-five children underwent a new RFA due to initial failure or recurrence. During the mean follow up of 5.5 ± 3.4 years, 107 (88.4%) remained without recurrence. There was no statistical difference regarding the results and the age at which the patient underwent the procedure. No child had persistent AVB or required a permanent pacemaker. CONCLUSION Catheter ablation is a safe and effective alternative therapy in children with recurrent tachycardias refractory to medical treatment.