Mariona Matas

ENHANCED DETECTION CRITERIA IN IMPLANTABLE DEFIBRILLATORS

Enhanced Tachycardia Detection Algorithm introduction: Enhanced detection criteria in third‐generation implantable defibrillators have been implemented to avoid inappropriate therapy of fast supraventricular arrhythmias. We prospectively analyzed the use of these criteria in patients with an implantable defibrillator with electrogram storing capability.

Radiofrequency catheter ablation for arrhythmic storm in patients with an implantable cardioverter defibrillator.

The aim of the study was to analyze the usefulness of RFA in controlling arrhythmic storm due to hemodynamically stable VT in a cohort of patients with an ICD and to evaluate the incidence of arrhythmic storm among patients with an ICD. A group of 13 (3%) of 403 consecutive ICD recipients were submitted to RFA of VT during an arrhythmic storm. Two additional patients were referred from other institutions. Standard criteria were used for VT endocardial ablation. A transcatheter epicardial approach was required in three patients. A total of 18 procedures were performed in 15 patients. A mean of 13.2 ± 9.7 pulses of RF were delivered. Clinical tachycardia was successfully ablated in 12 (80%) patients. One patient died in incessant VT, 1 patient underwent heart transplant, and 1 was treated with direct current ablation. During a mean follow‐up of 12 ± 17 months, only two patients suffered a single episode of VT. Arrhythmic storm requiring VT ablation was uncommon among patients with an ICD and occurred late after ICD implantation. The arrhythmic episode was successfully controlled in the majority of patients with endocardial or epicardial RFA. (PACE 2004; 27:971–975)

Atrial fibrillation induced by atrioventricular nodal reentrant tachycardia

In 4 patients with recurrent episodes of paroxysmal atrial fibrillation as the only documented arrhythmia, electrophysiologic study showed that atrial fibrillation originated after a very fast transition from atrioventricular nodal reentrant tachycardia. Recognition of atrioventricular nodal reentrant tachycardia as the triggering factor for atrial fibrillation has important therapeutic consequences.

Radiofrequency Ablation of Anteroseptal, Para-Hisian, and Mid-Septal Accessory Pathways Using a Simplified Femoral Approach

Feasibility of RF ablation using a simplified two‐catheter technique from a femoral approach was studied in 97 consecutive patients with a manifest or concealed accessory pathway located at the anteroseptal, mid‐septal, and para‐Hisian areas. BF was applied at the site with the shortest V‐delta interval or the earliest retrograde atrial activation during orthodromic tachycardia or right ventricular pacing. Ablation was initially successful in 88 of’97 patients (91 %). Success rate was 94% (16/17) for anteroseptal. 94% (39/43] for para‐Hisian, and 89% (33/37) for mid‐septal accessory pathways, without differences between manifest and concealed pathways for any of the locations. Mean number of BF pulses was 8 ± 5 for anteroseptal, 6 ± 6 for mid‐septal, and 12 ± 13 for para‐Hisian accessory pathways. Two patients (2%) required implantation of a permanent pacemaker for complete A V block. At a mean follow‐up of 27 ± 14 months, four patients with previous manifest preexcitation experienced resumption of intermittent preexcitation, but only one required a second successful procedure for recurrence of palpitations. RF ablation can be used effectively and without impairment of normal AV conduction in the majority of patients with anteroseptal, para‐Hisian, and mid‐septal accessory pathways using a simplified two‐catheter technique from a femoral approach.

Electrocardiographic versus echocardiographic optimization of the interventricular pacing delay in patients undergoing cardiac resynchronization therapy.

Electrocardiographic VV Optimization. Introduction: Echocardiographic optimization of the VV interval may improve CRT response, but it is time‐consuming and not routinely performed. The aim of this study was to compare the response to cardiac resynchronization therapy (CRT) when the interventricular pacing (VV) interval was optimized by Tissue Doppler Imaging (TDI) to CRT response when it was optimized following QRS width criteria.

Feasibility of early discharge after acute Q wave myocardial infarction in patients not receiving thrombolytic treatment

OBJECTIVES The purpose of this study was to analyze the feasibility of early discharge (4 days) after acute myocardial infarction in patients not receiving thrombolytic therapy by first identifying predictors of short-term prognosis and then testing the derived risk profile in an independent cohort of patients. BACKGROUND Previous studies have shown that early discharge after acute myocardial infarction is possible. However, physicians are reluctant to shorten the standard 7- to 10-day hospital stay, presumably because of difficulty in selecting low risk patients. METHODS From January 1985 to November 1986, 358 patients with acute myocardial infarction who did not receive thrombolytic therapy were screened. Those with a Q-wave infarction showing no complications on day 4 were considered candidates for early discharge and were transferred to the ward for a mean of 12 days. During this period, we looked for any event (cardiac or noncardiac) that would have prompted readmission if the patient had been previously discharged. Univariate and multiple regression analysis were performed to identify predictors of these events among 25 baseline variables. The derived risk profile was tested in an independent validation cohort. RESULTS One hundred five (29.3%) of the 358 patients were free of symptoms on day 4, and 29 (27.6%) had at least one cardiac event, including four deaths and one reinfarction. Multivariate analysis selected diabetes, ejection fraction < 40% and age as independent predictors of events. Using the risk profile, 18 (13.2%) of the 136 validation cohort patients were categorized as low risk, and only 1 of them had a major event (progressive angina). Sensitivity for the risk profile was high (91%), but specificity was low (34%). CONCLUSIONS The use of simple clinical variables may allow the safe reduction of hospital stay after infarction in selected patients. However because the proportion of candidates for early discharge is small (12.6%), it seems unlikely that the current policies on length of hospital stay will change in the near future.

Radiofrequency catheter ablation of atriofascicular accessory pathways guided by discrete electrical potentials recorded at the tricuspid annulus.

Background: The purpose of this study was to test the feasibility of using the recording of discrete electrical potentials to guide radiofrequency catheter ablation of atriofascicular accessory pathways with Mahaim‐like properties. Methods and Results: Four patients (3 females, 1 male) who fulfilled criteria for having atriofascicular accessory pathways with Mahaim‐like properties and preexcited reciprocating tachycardia underwent radiofrequency catheter ablation. The mean age was 35 years (range 27–47). Symptoms were present for a mean of 10.5 years (range 6–18). Recording of discrete electrical potentials of the atriofascicular pathway was attempted by mapping the tricuspid annulus in sinus rhythm, during atrial pacing, and during reciprocating tachycardia. During atrial pacing, a mean of seven radiofrequency pulses (range 1–14), delivered to the tricuspid annulua at the area where electrical potentials were recorded, eliminated conduction through the atriofascicular accessory pathway in all patients. No complications occurred. Tachycardia did not reoccur during a mean follow‐up of 5 months (range 3–9). Conclusions: Recording of discrete electrical potentials at the tricuspid annulus identifies an optimal ablation site where radiofrequency current can safely eliminate conduction through atriofascicular accessory pathways with Mahaim‐like properties.

Arrhythmia recurrence in patients with a healed myocardial infarction who received an implantable defibrillator: analysis according to the clinical presentation

OBJECTIVES The purpose of this study was to analyze the type of arrhythmia recurrence, based on stored electrograms, in patients with a healed myocardial infarction (MI) who received an implantable defibrillator. BACKGROUND Previous studies suggest that patients presenting with cardiac arrest (CA) tend to recur as ventricular fibrillation (VF), whereas those suffering sustained monomorphic ventricular tachycardia (SMVT) tend to recur as SMVT. However, these data have not been confirmed in a homogeneous population of patients with MI. METHODS A total of 88 patients was divided into three groups according to their clinical presentation: SMVT (n = 57), CA (n = 16) or syncope (n = 15). RESULTS There were no significant differences in clinical characteristics among groups. In the electrophysiologic study SMVT was induced in 93%, 94% and 80% of patients, respectively (p = NS). During the follow-up period, 52% of patients presented a total of 671 episodes of ventricular arrhythmia treated by the defibrillator. All recurrences were as SMVT except for one VF. There were 610 episodes of SMVT treated with antitachycardia pacing, with an effectiveness of 96%. A total of 61 episodes was treated initially with cardioversion. No differences in the probability of recurrence were observed among groups, although the statistical power was low (50%). CONCLUSIONS In patients with an old infarction and malignant ventricular arrhythmias, the majority of recurrences are due to SMVT independently of the clinical presentation (SMVT, CA or syncope) or the induced arrhythmia at the electrophysiologic study. The programming of an antitachycardia zone seems to be appropriate also for patients who present with CA or syncope.

Radiofrequency ablation of a posteroseptal atrioventricular accessory pathway in a left-sided tricuspid ring with Ebsteinlike anomaly in a patient with congenitally corrected transposition of the great arteries.

Radiofrequency ablation successfully eliminated a posteroseptal accessory pathway in a left‐sided tricuspid ring with Ebsteinlike anomaly in a patient with a congenially corrected transposition of the great arteries.

Fusion‐Optimized Intervals (FOI): A New Method to Achieve the Narrowest QRS for Optimization of the AV and VV Intervals in Patients Undergoing Cardiac Resynchronization Therapy

Optimization of atrioventricular (AV) and interventricular (VV) intervals may improve cardiac resynchronization therapy (CRT) response but is a complex task. Fusion with intrinsic conduction may increase the benefit of CRT. The aim was to describe fusion‐optimized intervals (FOI), a new method of optimizing CRT based on QRS duration.