Rafael Peinado

Mechanisms of Sustained Ventricular Tachycardia in Myotonic Dystrophy Implications for Catheter Ablation

BACKGROUND Ventricular arrhythmias have been documented and linked to the high incidence of sudden death seen in patients with myotonic dystrophy. However, their precise mechanism is unknown, and their definitive therapy remains to be established. METHODS AND RESULTS We studied 6 consecutive patients with myotonic dystrophy and sustained ventricular tachycardia by means of cardiac electrophysiological testing. Particular attention was paid to establish whether bundle-branch reentry was the tachycardia mechanism, and when such was the case, radiofrequency catheter ablation of either the right or left bundle branch was performed. Clinical tachycardia was inducible in all patients and had a bundle-branch reentrant mechanism. In 1 patient, 2 other morphologies of sustained tachycardia were also inducible, neither of which had ever been clinically documented, and both had a bundle-branch reentrant mechanism. Ventricular tachycardia was no longer inducible after bundle-branch ablation, except for a nonclinically documented and nonsustained ventricular tachycardia in the only patient who had apparent structural heart disease. CONCLUSIONS A high clinical suspicion of bundle-branch reentrant tachycardia is justified in patients with myotonic dystrophy who exhibit wide QRS complex tachycardia or tachycardia-related symptoms. Because catheter ablation will easily and effectively abolish bundle-branch reentrant tachycardia, myotonic dystrophy should always be considered in patients with sustained ventricular tachycardia. This is especially true if no apparent heart disease is found.

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).

Guías de práctica clínica de la Sociedad Española de Cardiología en arritmias cardíacas

Se presentan las conclusiones consensuadas de un panel de arritmologos, convocados por la Sociedad Espanola de Cardiologia, acerca del enfoque terapeutico de las arritmias cardiacas. El manuscrito se ha dividido en 7 secciones, que representan areas de afinidad en cuanto a terapeutica: 1. Taquicardias supraventriculares no asociadas al sindrome de Wolff-Parkinson-White. 2. Sindromes de preexcitacion. 3. Fluter auricular. 4. Fibrilacion auricular. 5. Arritmias ventriculares no sostenidas. 6. Taquicardias ventriculares sostenidas (en ausenciade sindrome de parada cardiaca). 7. Sindrome de parada cardiaca por taquiarritmia ventricular. En cada una de las secciones se emiten recomendaciones en cuanto a las distintas opciones terapeuticas, farmacologicas y no farmacologicas, asi como en cuanto a los subgrupos de pacientes subsidiarios de cada una de ellas.

Bundle-Branch Reentry and the Postpacing Interval After Entrainment by Right Ventricular Apex Stimulation: A New Approach to Elucidate the Mechanism of Wide-QRS-Complex Tachycardia With Atrioventricular Dissociation

Background —Diagnosis of bundle-branch reentry ventricular tachycardia (BBR-VT) by the standard approach is challenging, and this may lead to nonrecognition of this tachycardia mechanism. Because the postpacing interval (PPI) after entrainment has been correlated with the distance from the pacing site to the reentrant circuit, BBR-VT entrainment by pacing from the right ventricular apex (RVA) should result in a PPI similar to the tachycardia cycle length (TCL). This factor may differentiate BBR-VT from other mechanisms of wide-QRS-complex tachycardia with AV dissociation, such as myocardial reentrant VT (MR-VT) or AV nodal reentrant tachycardia (AVNRT), in which the circuit is usually located away from the RVA. Methods and Results —Transient entrainment by RVA pacing was attempted in 18 consecutive BBR-VTs and finally achieved in 13. Results were compared with those found in 59 consecutive MR-VTs and 50 consecutive AVNRTs. The mean PPI−TCL difference was significantly (P <0.0001) shorter in the BBR-VT group (9±11 ms) than in the MR-VT (109±48 ms) and the AVNRT (150±29 ms) groups. No BBR-VT showed a PPI−TCL >30 ms (range −12 to 24 ms). Except for 2 MR-VTs, no MR-VT (range 21 to 211 ms) or AVNRT (range 100 to 215 ms) showed a PPI−TCL <30 ms. Conclusions —A PPI−TCL >30 ms, after entrainment by RVA stimulation, makes BBR-VT unlikely. Conversely, a PPI−TCL <30 ms is suggestive of BBR-VT but should lead to further investigation by use of conventional criteria.

Incidence and Predictors of Sudden Cardiac Arrest in Adults With Congenital Heart Defects Repaired Before Adult Life

Many adult survivors of repaired congenital heart disease (CHD) are at premature risk of death. Sudden cardiac arrest (SCA) is 1 of the leading causes of death but little is known about determinants for SCA in adults with repaired lesions. We sought to determine incidence and risk factors for SCA in a study population of 936 adults with previously repaired CHD who had completed follow-up at a single tertiary center during a mean period of 9 ± 7 years. Mean age at first examination in our institution was 21 ± 7 years. Diagnostic categories included tetralogy of Fallot (216), coarctation of the aorta (157), transposition complexes (99), single ventricle (55), and other CHD (409). During a total follow-up of 8,387 person-years, 22 patients (2.6 per 1,000 person-years) presented with SCA. Incidence of SCA varied widely between specific lesions; the highest incidence was observed in transposition complexes (10 per 1,000 person-years). Independent predictors of SCA were retrospectively identified using multivariate Cox proportional hazard modeling. Age at initial examination and severely impaired subaortic ventricular systolic function were independent risk factors for SCA (severe subaortic ventricular systolic dysfunction, adjusted hazard ratio 29, 95% confidence interval 11 to 72, p <0.001). SCA occurred in 23% of patients with severe subaortic ventricular systolic dysfunction versus 0.7% of patients with nonsevere decreased subaortic ventricular function (p <0.001). In conclusion, severe subaortic ventricular systolic dysfunction is a dominant multivariate predictor of SCA in an unselected population of adult survivors after surgery for CHD. Our data support the consideration of primary prevention strategies in these patients.

EuroEco (European Health Economic Trial on Home Monitoring in ICD Patients): a provider perspective in five European countries on costs and net financial impact of follow-up with or without remote monitoring.

Aim Remote follow-up (FU) of implantable cardiac defibrillators (ICDs) allows for fewer in-office visits in combination with earlier detection of relevant findings. Its implementation requires investment and reorganization of care. Providers (physicians or hospitals) are unsure about the financial impact. The primary end-point of this randomized prospective multicentre health economic trial was the total FU-related cost for providers, comparing Home Monitoring facilitated FU (HM ON) to regular in-office FU (HM OFF) during the first 2 years after ICD implantation. Also the net financial impact on providers (taking national reimbursement into account) and costs from a healthcare payer perspective were evaluated. Methods and results A total of 312 patients with VVI- or DDD-ICD implants from 17 centres in six EU countries were randomised to HM ON or OFF, of which 303 were eligible for data analysis. For all contacts (in-office, calendar- or alert-triggered web-based review, discussions, calls) time-expenditure was tracked. Country-specific cost parameters were used to convert resource use into monetary values. Remote FU equipment itself was not included in the cost calculations. Given only two patients from Finland (one in each group) a monetary valuation analysis was not performed for Finland. Average age was 62.4 ± 13.1 years, 81% were male, 39% received a DDD system, and 51% had a prophylactic ICD. Resource use with HM ON was clearly different: less FU visits (3.79 ± 1.67 vs. 5.53 ± 2.32; P < 0.001) despite a small increase of unscheduled visits (0.95 ± 1.50 vs. 0.62 ± 1.25; P < 0.005), more non-office-based contacts (1.95 ± 3.29 vs. 1.01 ± 2.64; P < 0.001), more Internet sessions (11.02 ± 15.28 vs. 0.06 ± 0.31; P < 0.001) and more in-clinic discussions (1.84 ± 4.20 vs. 1.28 ± 2.92; P < 0.03), but with numerically fewer hospitalizations (0.67 ± 1.18 vs. 0.85 ± 1.43, P = 0.23) and shorter length-of-stay (6.31 ± 15.5 vs. 8.26 ± 18.6; P = 0.27), although not significant. For the whole study population, the total FU cost for providers was not different for HM ON vs. OFF [mean (95% CI): €204 (169–238) vs. €213 (182–243); range for difference (€−36 to 54), NS]. From a payer perspective, FU-related costs were similar while the total cost per patient (including other physician visits, examinations, and hospitalizations) was numerically (but not significantly) lower. There was no difference in the net financial impact on providers [profit of €408 (327–489) vs. €400 (345–455); range for difference (€−104 to 88), NS], but there was heterogeneity among countries, with less profit for providers in the absence of specific remote FU reimbursement (Belgium, Spain, and the Netherlands) and maintained or increased profit in cases where such reimbursement exists (Germany and UK). Quality of life (SF-36) was not different. Conclusion For all the patients as a whole, FU-related costs for providers are not different for remote FU vs. purely in-office FU, despite reorganized care. However, disparity in the impact on provider budget among different countries illustrates the need for proper reimbursement to ensure effective remote FU implementation.

Identification of concealed posteroseptal Kent pathways by comparison of ventriculoatrial intervals from apical and posterobasal right ventricular sites.

BACKGROUND The differential diagnosis of supraventricular tachycardia with concentric atrial activation usually requires the inducibility of sustained tachycardia and needs a complex and time-consuming electrophysiological evaluation. To develop a simple test to establish if ventriculoatrial conduction uses a posteroseptal accessory pathway or the normal conduction system, we compared the ventriculoatrial intervals during right ventricular pacing from apical and posterobasal sites. METHODS AND RESULTS Continuous pacing was performed from an apical and a posterobasal right ventricular site in 34 patients with retrograde conduction over the normal conduction system (group A) and in 22 patients with conduction over a posteroseptal accessory pathway (group B). During apical pacing, ventriculoatrial intervals in group A (176 +/- 40 milliseconds) were not significantly different than those in group B (197 +/- 47 milliseconds, P = NS). During posterobasal pacing, group B patients had significantly shorter ventriculoatrial intervals than group A patients (158 +/- 46 versus 197 +/- 39 milliseconds, P < .01). The difference between the ventriculoatrial interval obtained during apical pacing and that obtained during posterobasal pacing (ventriculoatrial index) discriminated between the two groups without overlapping: It was positive in all group B patients (39 +/- 19; range, +10 to +70 milliseconds) and negative in all except two group A patients (-21 +/- 13; range, -50 to +5 milliseconds; P < .001). CONCLUSIONS This ventriculoatrial index can identify accurately and in the absence of tachycardia whether concentric retrograde conduction is proceeding over a posteroseptal accessory pathway or over the normal conduction system.

Development of a questionnaire to measure health-related quality of life (HRQoL) in patients with atrial fibrillation (AF-QoL)

BackgroundThe Health-Related Quality of Life (HRQoL) assessment in atrial fibrillation (AF) patients has traditionally been carried out in a poorly standardised fashion, or via the use of non disease-specific HRQoL questionnaires. The development of a HRQoL questionnaire with a good measuring performance will allow for a standardised assessment of the impact of this disease on the patients daily living.MethodsA bibliography review was conducted to identify the most relevant domains of daily living in AF patients. Subsequently, a focus group was created with the aid of cardiologists, and 17 patients were interviewed to identify the most-affected HRQoL domains. A qualitative analysis of the interview answers was performed, which was used to develop a pilot questionnaire administered to a 112-patient sample. Based on patient responses, an analysis was carried out following the statistical procedures defined by the Classical Test Theory (CTT) and the Item Response Theory (IRT). Reliablility was assessed via Cronbachs coefficient alpha and item-total score correlations. A factorial analysis was performed to determine the number of domains. For each domain, a Rasch analysis was carried out, in order to reduce and stand hierarchically the questionnaire items.ResultsBy way of the bibliography review and the expert focus group, 10 domains were identified. The patient interviews allowed for the identification of 286 items that later were downsized to 40 items. The resultant preliminary questionnaire was administered to a 112-patient sample (pilot study). The Rasch analysis led to the definition of two domains, comprising 7 and 11 items respectively, which corresponded to the psychological and physical domains (18 items total), thereby giving rise to the initial AF-QoL-18 questionnaire. Cronbachs coefficient alpha was acceptable (0.91).ConclusionAn initial HRQoL questionnaire, AFQoL-18, has been developed to assess HRQoL in AF patients.

Initial outcome of percutaneous balloon valvuloplasty in rheumatic tricuspid valve stenosis

Abstract Percutaneous balloon valvuloplasty (PBV) has been used as an effective treatment for some cases of valvular stenosis, mainly in the mitral, 1 pulmonary 2 and aortic 3 valves. Less experience has been achieved with this procedure for valvular tricuspid stenosis. 4–7 We present the immediate results of 5 cases of PBV in stenotic tricuspid valves.

Transient Entrainment of Bundle-Branch Reentry by Atrial and Ventricular Stimulation Elucidation of the Tachycardia Mechanism Through Analysis of the Surface ECG

BACKGROUND Different responses to entrainment have been reported in relation to the pacing site of a variety of tachycardias. However, transient entrainment of bundle-branch reentrant tachycardia (BBRT) has not been investigated systematically. METHODS AND RESULTS We attempted entrainment of 13 BBRTs in 9 patients by pacing first the right ventricle and then the right atrium. The initial pacing cycle length (CL) was 10 ms faster than the tachycardia CL. Subsequent pacing sequences were performed with 5- to 10-ms CL decrements until tachycardia termination or loss of postatropine 1:1 AV conduction. Both full ventricular-paced and AV-conducted QRS complex references were obtained during sinus rhythm pacing from the same sites and with similar CL as during entrainment. Transient entrainment was achieved by ventricular and atrial stimulation in 11 and 8 tachycardias, respectively. Constant fusion was always present during entrainment by ventricular stimulation. There was no change in the QRS complex (orthodromically concealed fusion) during entrainment by atrial stimulation in 6 of 6 tachycardias with left bundle-branch block morphology and in 1 of 2 tachycardias with right bundle-branch block morphology. CONCLUSIONS BBRT, especially if it has a left bundle-branch block morphology, can be differentiated from other wide-QRS-complex tachycardia mechanisms through analysis of the ECGs recorded during tachycardia entrainment by atrial and ventricular stimulation. This diagnostic approach may be especially useful when it is difficult to record a stable or sufficiently sized His bundle electrogram or when spontaneous changes in the ventricular CL precede similar changes in the His bundle CL.