Luis Tercedor

Mechanism of Syncope in Patients With Heart Disease and Negative Electrophysiologic Test

Background—In patients with syncope and structural heart disease, syncope is suspected to be attributable to a primary cardiac arrhythmia, but little is known of its mechanism when electrophysiologic study is unremarkable. Methods and Results—We applied an implantable loop recorder in 35 patients with overt heart disease at risk of ventricular arrhythmia, because these were patients with previous myocardial infarction or cardiomyopathy with depressed ejection fraction or nonsustained ventricular tachycardia in whom an electrophysiologic study was unremarkable. During a follow-up of 3 to 15 months, syncope recurred in 6 patients (17%) after a mean of 6±5 months; in 3 patients, the mechanism of syncope was bradycardia with long pauses (sudden-onset AV block in 2 cases and sinus arrest in 1 case); in 1 patient, there was stable sinus tachycardia; and in 2 patients, who had chronic atrial fibrillation, there was an increase in ventricular rate. A total of 23 episodes of presyncope were documented in 8 patients (23%): no rhythm variation or mild tachycardia in 12 cases, paroxysmal atrial fibrillation or atrial tachycardia in 10 cases, and sustained ventricular tachycardia in 1 case. No patient died during the study period nor suffered from injury attributable to syncopal relapse. Conclusions—The patients with unexplained syncope, structural heart disease, and negative electrophysiologic study had a favorable medium-term outcome with no case of death and a low recurrence rate of syncope without related injury. The mechanism of syncope was heterogeneous, and ventricular tachyarrhythmia was unlikely.

Incidence and Clinical Significance of Multiple Consecutive, Appropriate, High-Energy Discharges in Patients With Implanted Cardioverter-Defibrillators

BACKGROUND Some patients with an automatic implantable cardioverter-defibrillator (ICD) suffer multiple appropriate, consecutive, high-energy discharges (MCDs) during follow-up. Such events might represent resistant ventricular arrhythmias and might have prognostic significance. METHODS AND RESULTS Eighty consecutive patients with an ICD were followed up for up to 82 months (mean, 21 +/- 19 months). Thirty-eight patients had survived an out-of-hospital cardiac arrest and 42 had recurrent ventricular tachycardia. During follow-up, 16 patients had MCD (group A), 26 patients had episodes of single appropriate discharges (group B), and 38 patients had no appropriate discharges (group C). Group A patients had worse functional status (P = .001), lower left ventricular ejection fractions (LVEFs) (P = .001), and lower survival rates (log rank, P = .003) than the remaining two groups of patients. Cox analysis showed LVEF (P = .001) to be an independent predictor of MCD. Independent predictors of death or heart transplant were MCD (P = .001), female sex (P = .001), age (P = .001), history of cardiac arrest (P = .003), and functional status (P = .003). The only independent predictor of total mortality was female sex (P = .002). Independent predictors of cardiac death were MCD (P = .007) and female sex (P = .018). Independent predictors of arrhythmic death were age (P = .001), female sex (P = .02), and MCD (P = .023). CONCLUSIONS In patients with an ICD, the development of MCD is an independent predictor of cardiac and arrhythmic mortality. If this finding is confirmed in larger studies, it may help to identify patients in whom other therapeutic alternatives, ie, heart transplantation, should be considered during follow-up after ICD implantation.

Comparison of radiofrequency catheter ablation of drivers and circumferential pulmonary vein isolation in atrial fibrillation: a noninferiority randomized multicenter RADAR-AF trial.

BACKGROUND Empiric circumferential pulmonary vein isolation (CPVI) has become the therapy of choice for drug-refractory atrial fibrillation (AF). Although results are suboptimal, it is unknown whether mechanistically-based strategies targeting AF drivers are superior. OBJECTIVES This study sought to determine the efficacy and safety of localized high-frequency source ablation (HFSA) compared with CPVI in patients with drug-refractory AF. METHODS This prospective, multicenter, single-blinded study of 232 patients (age 53 ± 10 years, 186 males) randomized those with paroxysmal AF (n = 115) to CPVI or HFSA-only (noninferiority design) and those with persistent AF (n = 117) to CPVI or a combined ablation approach (CPVI + HFSA, superiority design). The primary endpoint was freedom from AF at 6 months post-first ablation procedure. Secondary endpoints included freedom from atrial tachyarrhythmias (AT) at 6 and 12 months, periprocedural complications, overall adverse events, and quality of life. RESULTS In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months after a single procedure but, after redo procedures, was noninferior to CPVI at 12 months for freedom from AF and AF/AT. Serious adverse events were significantly reduced in the HFSA group versus CPVI patients (p = 0.02). In persistent AF, there were no significant differences between treatment groups for primary and secondary endpoints, but CPVI + HFSA trended toward more serious adverse events. CONCLUSIONS In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months but was noninferior to CPVI at 1 year in achieving freedom of AF/AT and a lower incidence of severe adverse events. In persistent AF, CPVI + HFSA offered no incremental value. (Radiofrequency Ablation of Drivers of Atrial Fibrillation [RADAR-AF]; NCT00674401).

Safety and feasibility of catheter ablation for atrioventricular nodal re-entrant tachycardia without fluoroscopic guidance

BACKGROUND Nonfluoroscopic intracardiac navigation systems reduce the dose of radiation in most ablation procedures. However, they have not been sufficiently studied as a sole guidance tool for electrode catheter handling. OBJECTIVE The purpose of our study was to assess the feasibility and safety of catheter ablation for atrioventricular nodal re-entrant tachycardia (AVNRT) without the use of fluoroscopy. METHODS We prospectively enrolled all of the patients with AVNRT (Group A) treated by catheter ablation guided only by a nonfluoroscopic intracardiac navigation system. These patients were compared with a matched control group of patients (Group B) who had undergone an ablation procedure for AVNRT guided only by fluoroscopy in the preceding months. We compared the success rate and the rate of complications and recurrences. We also compared the procedure and radiofrequency times. RESULTS Fifty patients were enrolled in each group. The procedure was successful in 100% in Group A versus 96% in Group B (P = .15). One patient in Group A and 4 patients in Group B suffered nonserious complications (P = NS). The mean fluoroscopy time in Group B was 18 +/- 16 min (range 3.5 to 77, total 924). In 1 case in Group A (2%), the use of fluoroscopy was required. Procedure and radiofrequency times did not differ between the 2 groups. A recurrence developed in 2 patients in each group (P = NS). CONCLUSIONS Catheter ablation for AVNRT without fluoroscopic guidance is feasible and safe, and does not prolong procedure time. The reduction in radiation dose is considerable for patients and professionals.

Evidence favoring the hypothesis that ventricular arrhythmias have prognostic significance in left ventricular hypertrophy secondary to systemic hypertension

In the present review 6 lines of evidence will be discussed that suggest a prognostic significance for ventricular arrhythmias in patients with systemic hypertension and left ventricular hypertrophy: (1) in patients with systemic hypertension there is a statistical relation between asymptomatic ventricular arrhythmias and left ventricular hypertrophy; (2) in nonhypertensive left ventricular hypertrophy the prognostic value of ventricular arrhythmias is well known; (3) left ventricular hypertrophy is related to sudden death in patients with systemic hypertension; (4) it is generally acknowledged that ventricular arrhythmias are a frequent cause of sudden death; (5) there is experimental evidence to support the arrhythmic risk of left ventricular hypertrophy; and (6) it has been recently demonstrated that ventricular arrhythmias influence mortality in patients with left ventricular hypertrophy secondary to systemic hypertension. However, whether asymptomatic ventricular arrhythmias are specific markers for more severe sustained arrhythmias, or just markers for a more severe stage of the disease, remains to be determined.

Diagnostic Approach to Unexplained Cardiac Arrest (from the FIVI-Gen Study)

Unexplained cardiac arrest (UCA) can be caused by low-penetrance genetic disorders. The aim of this cross-sectional study is to assess the usefulness of a new diagnostic protocol: Thirty-five patients were recruited from 9 Spanish centers. Electrocardiogram, echocardiogram, and coronary catheterization were used to rule out electrical or structural heart disease in all subjects. Patients underwent pharmacologic tests with epinephrine and flecainide, followed by assessment of family members using electrocardiogram and echocardiogram, and next-generation genetic sequencing to analyze 126 genes if all the other test results were negative. A firm diagnosis of channelopathy required phenotypic proof of the condition in unmasking tests, the presence of a pathogenic variant consistent with the phenotype observed, and/or co-segregation of the mutation found in a family members phenotype. A firm diagnosis was made in 18 cases. The diagnoses were 7 Brugada syndrome, 5 catecholaminergic polymorphic ventricular tachycardia, 3 long QT syndrome, 2 early repolarization syndrome, and 1 short QT syndrome. Pharmacologic testing was the most frequent method of diagnosis. In 5 cases, the diagnosis was made based on positive genetic testing without phenotypic alterations. In conclusion, this sequential diagnostic protocol allows diagnoses to be made in approximately half of the UCA cases. These diagnoses are low clinical penetrance channelopathies. If interpreted carefully, genetic tests can be a useful tool for diagnosing UCA without a phenotype.

A Zero-Fluoroscopy Approach to Cavotricuspid Isthmus Catheter Ablation: Comparative Analysis of Two Electroanatomical Mapping Systems

Electroanatomical mapping systems have reduced the amount of fluoroscopy required to ablate the cavotricuspid isthmus. The aims of this study are to evaluate the feasibility and safety of a zero‐fluoroscopy approach to cavotricuspid isthmus catheter ablation using the Carto®3 system (Biosense Webster, Diamond Bar, CA, USA) and to compare the results of this approach with those of the zero‐fluoroscopy approach using the Ensite‐NavX™ system (St. Jude Medical, St. Paul, MN, USA).

Cavotricuspid isthmus catheter ablation without the use of fluoroscopy as a first-line treatment.

Cavotricuspid Isthmus Ablation Without Fluoroscopy. Introduction and Objectives: The use of intracardiac navigation systems has enabled a significant reduction of the radiation dose in the majority of ablation procedures. The purpose of this study is to evaluate the feasibility and safety of cavotricuspid isthmus ablation without the use of fluoroscopy as a first‐line treatment.

Radiofrequency catheter ablation of ventricular tachycardia from the right ventricle late after myocardial infarction

In summary, this case illustrates how complex VT circuits may be. If the findings of this case are substantiated with additional cases, mapping and radiofrequency energy application from right ventricle would have to be considered in VT with left bundle branch blocks QRS morphology, whenever ablation from the left ventricule is ineffective.

Guías de práctica clínica de la Sociedad Española de Cardiología sobre requerimientos y equipamiento en electrofisiología

.La evolucion, tanto cualitativa como cuantitativa, experimentada por la electrofisiologia en los ultimos anos ha llevado a la necesidad de crear unidades especificas dedicadas al manejo de los pacientes con arritmias cardiacas. En estas guias se consideran las necesidades materiales y humanas minimas con las que debe contar una unidad de arritmias.