Agustín Bortone

Long‐Term Follow‐Up of Biventricular Pacing Using a Totally Endocardial Approach in Patients with End‐Stage Cardiac Failure

Background: Besides standard left ventricular (LV) stimulation via the coronary sinus, a transseptal approach allows left ventricular endocardial stimulation. We report our long‐term observations with biventricular stimulation, using a strictly endocardial system for patients presenting with severe congestive heart failure.

Unipolar signal modification as a guide for lesion creation during radiofrequency application in the left atrium: prospective study in humans in the setting of paroxysmal atrial fibrillation catheter ablation.

Background—In patients treated for paroxysmal atrial fibrillation, the pulmonary vein (PV) reconnection rate is substantial and may be related to the lack of transmurality achievement while performing PV isolation (PVI). It has been experimentally demonstrated that positive unipolar atrial electrogram completion, when applying radiofrequency energy, was associated with transmural lesions. In this regard, we seek to determine whether the unipolar signal modification may be an appropriate end point for point-by-point radiofrequency application and find out whether it could improve the paroxysmal atrial fibrillation ablation results in humans. Methods and Results—Fifty consecutive patients (61±8 years old, 41 men) with paroxysmal atrial fibrillation underwent PVI using Carto and Lasso. Each radiofrequency application lasted until development of a completely positive unipolar electrogram. Fifty patients (63±9 years old, 40 men), who previously underwent PVI following the standard approach of our institution, corresponded to the control group. All PVs were isolated in all patients of both groups. However, the procedural and ablation times were significantly lower in the unipolar group compared with those of the control group, whereas the PV reconnection rate, after 30 minutes of waiting time, was not significantly different. Overall, 21±4 months after 1 PVI session, the sinus rhythm maintenance rate without antiarrhythmic drugs was significantly higher (P=0.027) in the unipolar group (88%) compared with that of the control group (70%). Conclusions—Unipolar signal modification is a useful end point for radiofrequency energy delivery in patients with paroxysmal atrial fibrillation who undergo PVI and leads to a substantial midterm sinus rhythm maintenance rate.

Monomorphic Ventricular Tachycardia Induced by Cardiac Resynchronization Therapy in Patient with Severe Nonischemic Dilated Cardiomyopathy

We report the case of a patient with severe nonischemic dilated cardiomyopathy in whom cardiac resynchronization therapy (CRT) was the source of incessant, drug‐resistant, monomorphic ventricular tachycardia (VT). VT recurrences were only resolutive with inactivation of CRT and reactivation of CRT reproduced VT occurrence. The possible pathophysiology of the VT and the potential ventricular proarrhythmic risk related to CRT are discussed. This report points out clearly that CRT can induce ventricular arrhythmias and suggests the need for CRT systematically associated with a defibrillation system.

Sinus rhythm restoration by catheter ablation in patients with long-lasting atrial fibrillation and congestive heart failure: impact of the left ventricular ejection fraction improvement on the implantable cardioverter defibrillator insertion indication

AIMS In the setting of congestive heart failure (CHF), atrial fibrillation (AF) ablation can improve clinical status and the left ventricular ejection fraction (LVEF) value. However, the impact of AF ablation on the implantable cardioverter defibrillator (ICD) indication has never been specifically addressed. METHODS AND RESULTS Study subject were six CHF (mean age 61.1 +/- 6.9 years, mean LVEF 25.8 +/- 7.3%) patients refractory to conventional medical treatment with long-lasting AF unresponsive to external cardioversion. Five patients had an idiopathic dilated cardiomyopathy (DCM) and one had an ischaemic cardiomyopathy (ICM). Their New York Heart Association (NYHA) class was III-IV. Two patients had renal insufficiency. No patient had left ventricular delay. All patients underwent AF ablation. LVEF and NYHA class were dramatically improved in the five DCM patients. New York Heart Association class, but not the LVEF, was improved in the ICM patient. A redo ablative procedure was undertaken in four of five DCM patients and in the ICM patient due to arrhythmia recurrence. Left ventricular ejection fraction and NYHA were improved again in the DCM patients (56 +/- 4.4%, I-II, respectively) and led to ICD indication preclusion. The LVEF remained low in the ICM patient (30%) and led to ICD insertion. Sinus rhythm has been stable during the 18.1 +/- 5.7 months follow-up period. CONCLUSION Atrial fibrillation ablation in CHF patients can improve both the clinical status of patients and their LVEF, especially among those affected by DCM. The LVEF improvement has the potential to preclude the indication for a primary prevention ICD insertion.

Feasibility and safety of same-day home discharge after radiofrequency catheter ablation

Interventional cardiology in a day-case setting might reduce logistic constraints on hospital resources. However, in contrast with coronary angioplasty, few data support the feasibility and safety of radiofrequency catheter ablation (RCA). The aim of this prospective, multicenter cohort study was to evaluate the feasibility and safety of RCA in 1,342 patients (814 men; mean age 57 +/- 17 years) considered eligible for ambulatory RCA, according to specific set of criteria, for common atrial flutter (n = 632), atrioventricular nodal reentrant tachycardia (n = 436), accessory pathways (n = 202), and atrial tachycardia (n = 72). Patients suitable for early discharge (4 to 6 hours after uncomplicated RCA) were scheduled for 1-month follow-up. Predictive factors for delayed complications were studied by multivariate analysis. Of the 1,342 enrolled patients, 1,270 (94.6%) were discharged the same day and followed for 1 month; no deaths occurred, and the readmission rate was 0.79% (95% confidence interval 0.30% to 1.27%). Six patients had significant puncture complications, 2 presented with symptomatic delayed pulmonary embolism, and 2 had new onset of poorly tolerated atrial flutter. None of these complications was life threatening. Multivariate analysis did not identify any significant independent predictors for delayed complications. In conclusion, these data suggest that same-day discharge after uncomplicated RCA for routine supraventricular arrhythmias is safe and may be applicable in clinical practice. This approach is known to be associated with significant patient satisfaction and cost savings and can be considered a first-line option in most patients who undergo routine ablation procedures.

Image-guided ablation of a ventricular tachycardia originating from the left aortic cusp.

A 76-year-old man was admitted with poorly tolerated ventricular tachycardia (VT, Fig. 1). He had no personal or familial history of ventricular arrhythmias. Baseline electrocardiogram (ECG) was normal. Echocardiography, coronary angiogram, and cardiac magnetic resonance imaging (MRI) showed no evidence of underlying structural heart disease, and there was no evidence of metabolic disorder. Angiographic LVEF was 58%. Electrophysiology (EP) study easily induced the clinical VT with left bundle branch block pattern and vertical axis. R waves in V1 and V2 suggested possible origin from the aortic cusps. An ablation procedure was

Clockwise loop of the ablation catheter in the left atrium: an easy and safe approach facilitating substrate modulation in the setting of atrial fibrillation ablation.

In the context of chronic atrial fibrillation (AF) ablation, substrate modulation has demonstrated its efficacy and its positive impact both into conversion of the AF either directly to sinus rhythm (SR) or to atrial tachycardia (AT) and into SR maintenance. However, substrate modulation, which can be performed either by linear lesions deployment or/and by targeting complex and fractionated atrial electrograms (CFAEs), can be a difficult task. We present a safe and non time‐consuming technique conceived in our center which we think is of interest for substrate modulation purpose in the AF ablation framework. This technique named the “clockwise loop approach” may permit both extensive and accurate mapping of a great amount of the LA and facilitation of LA linear lesions deployment.

Elimination of the Negative Component of the Unipolar Atrial Electrogram as an In Vivo Marker of Transmural Lesion Creation Acute Study in Canines

Background—It has been experimentally shown that elimination of the negative component of the unipolar atrial electrogram (R morphology completion) during radiofrequency applications reflects transmural lesions creation. Subsequently, it has been clinically suggested that such a transmurality can be either irreversible or reversible. The present study is aimed to determine, at the histological level, whether transmural lesions, assessed by R morphology completion, might indeed be reversible in some circumstances or not. Methods and Results—In 6 Mongrel hound dogs, superior and inferior vena cavae were isolated and individual lesions were created in the right atrium using radiofrequency energy (30 W/48°C/17 mL/min as presettings and 10g of force in average) under CARTO guidance. Five types of lesions were created; R+0: termination of ablation at the time of R morphology completion; R+5, R+10, or R+20: extension of ablation for 5, 10, or 20 seconds, respectively, after R morphology achievement; and conventional: radiofrequency applications lasting 30 seconds irrespective of the atrial electrogram modification. All conventional, R+5, R+10, and R+20 lesions were necrotic and transmural, whereas some R+0 lesions were not (comprising a part of necrosis and a part of reversible cell damage). Interestingly, surrounding organ injuries were observed after conventional, R+10, and R+20 radiofrequency applications but were not observed after R+0 and R+5 applications. Conclusions—Elimination of the negative component of the unipolar atrial electrogram reflects, in general, irreversible transmural necrosis creation. In some cases, however, it translates transmural lesion only (with potential reversibility) likely related to transient cell damage creation.

Complete atrioventricular block and asystole in a patient with an inferior acute myocardial infarction: What is the mechanism?

n 85-year-old woman with an acute myocardial infarcion associated with complete atrioventricular (AV) block Figure 1A) was referred to our institution. After discusion with the patient’s family, the patient was treated onservatively. Several hours after admission, a sudden bsence of the patient’s escape rhythm concurrent with yncope occurred (Figure 1B). After prompt cardiopulonary resuscitation, a quadripolar catheter was placed

Gradual power titration using radiofrequency energy: a safe method for slow-pathway ablation in the setting of atrioventricular nodal re-entrant tachycardia.

AIMS In the setting of atrioventricular nodal re-entrant tachycardia (AVNRT), radiofrequency (RF) catheter ablation of the slow-pathway (SP) ensures excellent outcome. However, the risk of complete heart block (CHB) remains real ( approximately 1%) and detrimental. This study reports on a gradual power titration approach using RF energy, which allows a significant decrease in CHB occurrence. METHODS AND RESULTS Slow-pathway ablation was performed in 468 patients (mean age 43.8 +/- 17.2 years, 311 women). Initial settings were 5 W, 60 degrees C, 120 s (temperature-controlled mode). The power was increased by steps of 5 W for every 5 s until slow-accelerated junctional rhythm was obtained, and then further increased to 10 W maximum above this value. The acute success rate, the mean RF pulses applied per patient, and the average power delivered per successful RF applications were 99%, 3.2 +/- 1.1, and 31.7 +/- 3.0 W, respectively. There were nine (1.9%) transient and reversible AV blocks, and one (0.2%) permanent CHB only necessitating pacemaker insertion. The recurrence rate was 3.6% and the follow-up period was 28.1 +/- 14.1 months. CONCLUSION Atrioventricular nodal re-entrant tachycardia RF ablation using gradual power titration is an efficient technique, capable of improving safety since it can decrease CHB occurrence.