Salvador Morell

Ablation or conservative management of electrical storm due to monomorphic ventricular tachycardia: differences in outcome

AIMS Electrical storm (ES) is a life-threatening condition that predicts bad prognosis. Treatment includes antiarrhythmic drugs (AAD) and catheter ablation (CA). The present study aims to retrospectively compare prognosis in terms of survival and ES recurrence in 52 consecutive patients experiencing a first ES episode. METHODS AND RESULTS Patients were admitted from 1995 to 2011 and treated for ES by conservative therapy (pharmacological, 29 patients) or by CA (23 patients), according to the physicians preference and time of occurrence, i.e. conservative treatments were more frequently administered during the first years of the study, as catheter ablation became more frequent as the years passed by. After a median follow-up of 28 months, no differences either in survival (32% vs. 29% P = 0.8) or in ES recurrence (38% in ablated vs. 57% in non-ablated patients, P = 0.29) were observed between groups. Low left ventricle ejection fraction (LVEF) was the only variable associated with ES recurrence in ablated patients. When including patients with LVEF > 25%, ES recurrence was significantly lower in ablated patients (24 months estimated risk of ES recurrence was 21% vs. 62% in ablated and non-ablated patients, respectively); however, no benefit in survival was observed. CONCLUSION Our data suggest that in most patients, especially those with an LVEF > 25%, catheter ablation following a first ES episode, decreases the risk of ES recurrence, without increasing survival.

Transvenous Ablation with High Frequency Energy for Atrioventricular Junctional (AV Nodal) Reentrant Tachycardia

SANJUAN, R., et al.: Transvenous ablation with high frequency energy for atrioventricular junctional (AV nodal) reentrant tachycardia We performed transcatheter AV junction ablation with high frequency energy in four patients with AV nodal reentrant tachycardia where extensive trials of several antiarrhythmic drugs failed to prevent further recurrences of tachycardia. Initially high frequency catheter ablation induced complete AV block in all patients. A recuperation of AV l:1 conduction followed some time later, persisting in follow‐up. No complications have been encountered in either the acute phase or the follow‐up (from 6 to 8 months; mean ± SD: 8.7 ± 2.5 months). The electrophysiological study was carried out 6 weeks following ablation, and all patients showed AV 1:1 conduction. No dual nodal pathway was encountered and no tachycardia could be triggered. With refinement of the method, the potential application of high frequency energy to interrupt intranodal or perinodal connections responsible for reentrant supraventricular tachycardia or to retard AV nodal conduction appears promising.

Prognostic value of pulmonary vascular resistance estimated by cardiac magnetic resonance in patients with chronic heart failure

AIMS Pulmonary arterial hypertension is known to be related to worse prognosis in patients with heart failure (HF). Quantification of pulmonary vascular resistance (PVR) still requires invasive right heart catheterization. Recent studies have shown an accurate method for non-invasive estimation of PVR by cardiac magnetic resonance (CMR). Our aim was to evaluate the prognostic value of PVR calculated by CMR in patients with congestive HF. METHODS AND RESULTS We calculated PVR by CMR in 132 patients [age 65.6 ± 13.1 years, left ventricular ejection fraction (LVEF) 35.1 ± 16.4%, ischaemic aetiology 40%] recently admitted for decompensated HF and derived to our cardiac imaging unit for diagnosis. Patients with cardiac events (readmission for HF or all-cause death) had higher values of PVR [6.77 ± 1.9 vs. 4.1 ± 1.6 Wood units (Wu), P < 0.001] during follow-up [mean 10.3 (1-31) months]. In multivariable Cox regression analysis, only a PVR ≥5.2 Wu [hazard ratio (HR) 4.27; 95% confidence interval (CI) 1.75-10.42; P < 0.001) and the presence of late gadolinium enhancement (LGE) on CMR (HR 2.24; 95% CI 1.03-4.86; P = 0.04) were independent predictors for adverse events at follow-up. CONCLUSION Non-invasive estimation of PVR by CMR might be useful for risk stratification of patients with chronic HF, irrespective of aetiology or LVEF.

Síncope y bloqueo de rama. Rendimiento del uso escalonado del estudio electrofisiológico y de la monitorización electrocardiográfica prolongada

INTRODUCTION AND OBJECTIVES The objective of this study was to determine the diagnostic yield of a stepped protocol involving an electrophysiologic study (EPS) and implantable loop recorders (ILR) in patients with syncope and bundle branch block (BBB). METHODS Eighty-five consecutive patients referred for syncope and BBB after initial non-diagnostic assessment underwent EPS including a pharmacological challenge with procainamide. Those patients without indication for defibrillator implantation received ILRs. Follow-up continued until diagnosis or end of battery life. RESULTS The EPS was diagnostic in 36 patients (42%). The most frequent diagnoses were paroxysmal atrioventricular block (AVB) (n=27), followed by ventricular tachycardia (VT) (n=6). All patients with VT had structural heart disease; left BBB was more prevalent in this group. Thirty-eight patients received ILRs and diagnosis was achieved in 13 (34%) of them; paroxysmal AVB (n=10) was the most frequent diagnosis. Median follow-up to diagnosis of paroxysmal AVB was 97 days (interquartile range 60-117 days). Paroxysmal AVB was more frequent in patients with right BBB and prolonged PR interval and/or axis deviation. We found no occurrence of VT or arrhythmic death during follow-up. CONCLUSIONS The most common etiology of syncope in patients with BBB was paroxysmal AVB, followed by VT. The stepped use of EPS and ILR in negative patients enables us to safely achieve a high diagnostic yield, given that VT is usually diagnosed during EPS.

Metformin and risk of long-term mortality following an admission for acute heart failure

Aims Optimal diabetic treatment in patients with established heart failure remains unclear. Metformin has been traditionally considered well tolerated in patients with cardiovascular disease, although there is scarce information regarding the prognostic implications of metformin in acute heart failure. We sought to evaluate the association between metformin therapy and risk of long-term mortality in patients discharged for decompensated heart failure. Methods We included 835 consecutive type 2 diabetic patients discharged from a cardiology department of a third-level center. All-cause mortality was considered as the primary endpoint and the effect of metformin therapy across the most representative subgroups in heart failure as a secondary endpoint. The association between metformin with all-cause mortality was evaluated by using a Cox regression method. Multivariate analysis included solid prognostic covariates in heart failure. Results At a mean follow-up of 2.4 ± 2 years, mortality rates were significantly lower in patients on treatment with metformin: 1.34 (1.04–1.65) × 10 vs. 2.24 (2.0–2.51) × 10 person-years (P < 0.001). Kaplan–Meier curve revealed a progressive separation of curves already observed during first months of follow-up (log-rank test P < 0.001). In multivariate analysis, this prognostic association remained significant. Conclusion In this cohort of patients with acute heart failure and diabetes, metformin appears to be well tolerated and may be associated with favorable clinical outcomes.

Outcome of patients with syncope beyond the implantable loop recorder

AIMS The implantation of an implantable loop recorder (ILR) leads to the diagnosis in about 35% of patients with syncope of unknown origin. Information on outcome of patients in whom a diagnosis is not reached during the lifetime of the device is scarce. The aim of our study is to determine the outcome of these patients in terms of syncope recurrence and survival. METHODS AND RESULTS An ILR was implanted to 97 patients with syncope of unknown origin. Patients were classified in groups A and B depending on their high or low risk, respectively, of having arrhythmic syncope. Diagnosis had not been reached in 60 patients (62%) when the ILR battery reached end operational life. Five patients were lost to follow up. During a median follow-up of 48 months after ILR explantation (interquartile range 36-56), 22 patients (40%) had recurrence of syncope (32% in group A vs. 48% in group B, P = 0.3). Syncopes with no neurally mediated profile were more frequent in group A (18 vs. 0%, P = 0.05) and neurally mediated profile syncopes were more frequent in group B (44 vs. 11%, P = 0.007). Five patients died, four of them in group A and 1 in group B (P = 0.4). No sudden or cardiac deaths were detected during follow-up. All deaths were due to non-cardiac causes. CONCLUSION Recurrent syncope is common in patients in whom a diagnosis is not established after the full battery life of an ILR. The prognosis of these patients seems to be good, without observed sudden or cardiac death.

mRNA PGC-1α levels in blood samples reliably correlates with its myocardial expression: study in patients undergoing cardiac surgery.

Objective: Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a transcriptional coactivator that has been proposed to play a protective role in mouse models of cardiac ischemia and heart failure, suggesting that PGC-1α could be relevant as a prognostic marker. Our previous studies showed that the estimation of peripheral mRNA PGC-1α expression was feasible and that its induction correlated with the extent of myocardial necrosis and left ventricular remodeling in patients with myocardial infarction. In this study, we sought to determine if the myocardial and peripheral expressions of PGC-1α are well correlated and to analyze the variability of PGC-1α expression depending on the prevalence of some metabolic disorders. Methods: This was a cohort of 35 consecutive stable heart failure patients with severe aortic stenosis who underwent an elective aortic valve replacement surgery. mRNA PGC-1α expression was simultaneously determined from myocardial biopsy specimens and blood samples obtained during surgery by quantitative PCR, and a correlation between samples was made using the Kappa index. Patients were divided into two groups according to the detection of baseline expression levels of PGC-1α in blood samples, and comparisons between both groups were made by chi-square test or unpaired Student’s t-test as appropriate. Results: Based on myocardial biopsies, we found that mRNA PGC-1α expression in blood samples showed a statistically significant correlation with myocardial expression (Kappa index 0.66, p<0.001). The presence of higher systemic PGC-1α expression was associated with a greater expression of some target genes such as silent information regulator 2 homolog-1 (x-fold expression in blood samples: 4.43±5.22 vs. 1.09±0.14, p=0.044) and better antioxidant status in these patients (concentration of Trolox: 0.40±0.05 vs. 0.34±0.65, p=0.006). Conclusions: Most patients with higher peripheral expression also had increased myocardial expression, so we conclude that the non-invasive estimation of mRNA PGC-1α expression from blood samples provides a good approach of the constitutive status of the mitochondrial protection system regulated by PGC-1α and that this could be used as prognostic indicator in cardiovascular disease. (Anatol J Cardiol 2016; 16: 622-9)

Intermittent atrial undersensing in single-lead VDD pacemakers in patients with bradycardia-sensitive repolarization: a possible mechanism for ventricular arrhythmia.

Intermittent atrial undersensing in patients with single-lead VDD pacemakers is regarded as being of limited clinical significance. Nevertheless, in patients with bradycardia-mediated repolarization abnormalities, undersensing could result in RR-interval oscillations due to changes in pacemaker mode and this could act as a trigger for the initiation of torsades de pointes. We report our findings in three patients, which demonstrate the functioning of this trigger mechanism for ventricular arrhythmias.

Infrasensado auricular intermitente de marcapasos VDD en pacientes con repolarización sensible a bradicardia: un potencial mecanismo de arritmias ventriculares

Es conocida la escasa repercusion clinica que tiene el fallo de sensado auricular intermitente en portadores de marcapasos VDD. No obstante, en pacientes con un sustrato de repolarizacion alterada mediada por bradicardia, este fallo puede generar oscilaciones RR ocasionadas por los cambios de modo, que pueden ser el desencadenante para iniciar una torsade de pointes. Exponemos nuestros hallazgos con 3 casos que ilustran este mecanismo desencadenante de arritmias ventriculares.

Rendimiento terapéutico de un protocolo prospectivo de cardioversión en la fibrilación auricular persistente

Introduction and objectives. The best therapeutic approach for persistent atrial fibrillation has yet to be defined. Our aim was to investigate the effects of cardioversion in unselected patients with persistent atrial fibrillation who were treated according to a strict protocol involving pretreatment, cardioversion, and follow-up. Methods. Consecutive patients with persistent atrial fibrillation of at least 1 months’ duration were included prospectively in a cardioversion protocol that involved standard antiarrhythmic pretreatment, with amiodarone being offered first, and follow-up. Results. The study included 295 patients, 87.5% of whom were taking the antiarrhythmic drug amiodarone. Sinus rhythm was restored in 92.5%, with pharmacologic cardioversion occurring in 9.5%. The recurrence rate was 33.5% in the first month and 54.9% by month 12. Antiarrhythmic treatment had to be modified in 10.8% of patients. Independent risk factors for recurrence during the first year after cardioversion were an atrial fibrillation duration greater than 1 year, previous cardioversion, and left ventricular dilatation. A simple risk scoring system was able to differentiate between subgroups of patients with a low, intermediate or high risk of recurrence in the first year after cardioversion. Conclusions. Sinus rhythm was maintained for 1 year after effective cardioversion in 45.1% of patients who received homogeneous antiarrhythmic pretreatment. There were few side effects. Recurrence can be predicted using clinical variables such as left ventricular dilatation, arrhythmia duration, and previous cardioversion.