Miguel A. Arias

Obstructive Sleep Apnea Syndrome Affects Left Ventricular Diastolic Function Effects of Nasal Continuous Positive Airway Pressure in Men

Background—The purpose of this study was to determine the role of obstructive sleep apnea syndrome (OSAS) as an independent risk factor for the development of left ventricular diastolic abnormalities. Moreover, we tested the hypothesis that nasal continuous positive airway pressure (nCPAP) improves such alterations in OSAS patients by eliminating apneic events. Methods and Results—In this prospective, randomized, placebo-controlled, double-blind crossover study, 27 consecutive newly diagnosed middle-aged OSAS men with neither controllable factors nor conditions affecting left ventricular diastolic function and 15 healthy control subjects were selected. OSAS patients were randomized to 12 weeks on sham nCPAP and 12 weeks on effective nCPAP application. Echocardiographic parameters, blood pressure recordings, and urinary catecholamine levels were obtained at baseline and after both treatment modalities. At baseline, an abnormal left ventricular filling pattern was present in 15 of the 27 OSAS patients and only in 3 of the 15 control subjects (P=0.020). Impaired relaxation was by far the most common abnormal pattern in both groups (11 and 3 patients, respectively). In OSAS patients, 12 weeks on effective nCPAP induced a significant increase in E/A ratio (P<0.01), as well as reductions in mitral deceleration (P<0.01) and isovolumic relaxation (P<0.05) times. Conclusions—OSAS can affect left ventricular diastolic function independently of other possible factors. Chronic application of nCPAP could avoid the progression of diastolic abnormalities, and indeed, it might reverse these alterations, at least in the initial stages before severe structural changes can be developed.

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).

Chronic right ventricular apical pacing: adverse effects and current therapeutic strategies to minimize them.

The permanent cardiac pacemaker is the only effective therapy for patients with symptomatic bradycardia and hundreds of millions are implanted worldwide every year. Despite its undisputed clinical benefits, the last two decades have drawn much attention to the negative effects associated with long-term pacing of the right ventricle (RV). Experimental and clinical studies have shown that RV pacing produces ventricular dyssynchrony, similar to that of left bundle branch block, with consequent detrimental effects on cardiac structure and function, with adverse clinical outcomes such as atrial fibrillation, heart failure and death. Although clinical evidence largely comes from subanalyses of pacemaker and implantable cardiac defibrillator studies, there is strong evidence that patients with reduced left ventricular function are at high risk of suffering from the detrimental effects of long-term RV pacing. Biventricular pacing in cardiac resynchronization therapy devices can prevent ventricular dyssynchrony and has emerged as an attractive option in this patient group with promising results and more clinical studies underway. Moreover, there is evidence that specific pacemaker algorithms that minimize RV pacing can reduce the negative effects of RV stimulation on cardiac function and may also prevent clinical deterioration. The extent of the long-term clinical effects of RV pacing in patients with normal ventricular function and how to prevent this are less clear and subject to future investigation.

Acute and mid-term outcomes of transvenous implant of a new left ventricular quadripolar lead versus bipolar leads for cardiac resynchronization therapy: Results from a single-center prospective database

BACKGROUND The purpose of this study was to evaluate the feasibility of the use of a quadripolar left ventricular (LV) lead for cardiac resynchronization therapy and to compare its acute and mid-term outcomes with those obtained with bipolar leads. Cardiac resynchronization exhibits a high incidence of problems involving the LV lead when conventional leads are used, and these problems may be minimized by using multipolar leads. METHODS We gathered clinical, implant, and follow-up data at 3 and 9 months from 21 consecutive patients in whom a quadripolar (Group Q) or bipolar (Group B) lead was used for a biventricular defibrillator implant. RESULTS The leads were successfully implanted in all of the patients. In Group B, more than one lead was used in 20% (p = 0.048) of cases. There were no clinical differences or differences in the implant parameters between the two groups except for the radiation dose, which was greater in group B (p = 0.035). The incidence of problems related to the LV lead during follow-up was higher in group B, but the difference was not significant (42.9% vs. 23.8%, p = 0.326). The use of more than one LV lead was the only variable that was significantly associated with lead-related problems during follow-up (p = 0.03; OR = 10.8; 95% CI 1.07-108.61). CONCLUSIONS The quadripolar lead was associated with excellent implantation success rates and mid-term performance. The multi-programmability capabilities of quadripolar leads facilitated the achievement of implant goals and helped to reduce problems during the implant and follow-up.

Síndromes de apneas-hipopneas durante el sueño e insuficiencia cardiaca

La insuficiencia cardiaca (IC) y los trastornos respiratorios durante el sueno son entidades que presentan una elevada prevalencia en la poblacion general y es frecuente la presencia de ambas en un mismo paciente. Diversos estudios epidemiologicos y fisiopatologicos indican que puede haber una relacion causal entre dichos trastornos y el desarrollo del sindrome de IC, tanto asociada con la presencia de disfuncion sistolica ventricular izquierda como en casos con funcion sistolica conservada. La presencia de trastornos respiratorios durante el sueno en enfermos con IC expone al sistema cardiovascular a hipoxemia intermitente, activacion simpatica y aumento de la precarga y poscarga ventricular que, a su vez, ponen en marcha una serie de mecanismos inflamatorios, oxidativos y neurohumorales que pueden favorecer la progresion de la enfermedad. Aunque aun no disponemos de datos que demuestren que el tratamiento de los trastornos respiratorios durante el sueno en enfermos con IC disminuye la mortalidad de esta poblacion, diversos trabajos demuestran una mejoria significativa en distintos parametros de estructura y funcion cardiovascular. En este trabajo se revisan las bases clinicas y los datos epidemiologicos, las relaciones fisiopatologicas y las implicaciones terapeuticas entre el sindrome de IC y los sindromes de apneas-hipopneas durante el sueno.

Differences in Ventriculoatrial Intervals During Entrainment and Tachycardia: A Simpler Method for Distinguishing Paroxysmal Supraventricular Tachycardia with Long Ventriculoatrial Intervals

VA Intervals to Distinguish PSVT. Introduction: Usefulness of the interval between the last pacing stimulus and the last entrained atrial electrogram (SA) minus the tachycardia ventriculoatrial (VA) interval in the differential diagnosis of supraventricular tachycardias with long (>100 ms) VA intervals has not been prospectively studied in a large series of patients. Our objective was to assess the usefulness of the difference SA–VA in diagnosing the mechanism of those tachycardias in patients without preexcitation. The results were compared with those obtained using the corrected return cycle (postpacing interval—tachycardia cycle length—atrioventricular [AV] nodal delay).

Permanent third-degree atrioventricular block as clinical presentation of an intracardiac bronchogenic cyst

Bronchogenic cysts are the most common primary cysts in the mediastinum. However, intracardiac bronchogenic cysts are uncommon. The present case represents a unique situation, in which an intracardiac bronchogenic cyst at the region of the atrioventricular node presented as permanent complete atrioventricular block (AVB) and was associated with the presence of an ostium secundum atrial septal defect.

Electrodo de desfibrilación Sprint Fidelis: experiencia de nueve centros en España

INTRODUCTION AND OBJECTIVES Sprint Fidelis defibrillation leads are prone to early failure. Most of the reported series come from a single institution. This paper describes the clinical experience in nine Spanish hospitals. METHODS Clinical, implant, and follow-up data of all patients with a Sprint Fidelis lead were analyzed. All cases of lead failure were identified, medium-term lead survival was calculated, and possible predictors for lead failure were determined. RESULTS In total, 378 leads in 376 patients were studied. The mean age (male 85.7%) was 64.9 ± 13.6 years. The majority of patients (59.8%) had ischemic heart disease. Mean left ventricular ejection fraction was 33.4% ± 14.5%. Left subclavian vein puncture was used in 74.8%. During a mean follow-up of 30.9 ± 14 months, 16 lead failures have occurred, with a lead survival of 96.1% at 36 months after implantation. Eleven of 16 lead failures were caused by failure of pace/sense conductors, 3 by defects in the high-voltage conductor, and 2 by defects in both types of conductors. A less depressed left ventricular ejection fraction was associated with an increased probability of lead failure (42.4% ± 16% vs. 33% ± 14.3%; P =.011). Three hospitals presented a rate of lead failure higher than 10%; the rate was less than 5% in the remaining 6 hospitals. CONCLUSIONS In this multicenter series of 378 leads, the 3-year estimated survival was higher than that reported in prior series. Clinical presentation of lead failures was similar to that reported previously. Left ventricular ejection fraction and hospital of implantation were variables associated to lead failure.

Comparison of Regular Atrial Tachycardia Incidence After Circumferential Radiofrequency versus Cryoballoon Pulmonary Vein Isolation in Real‐Life Practice

Postablation atrial tachycardia (AT) is a significant complication following radiofrequency (RF) pulmonary vein isolation (PVI). Cryoballoon (CB) ablation is an alternative technique for PVI that appears to have a low incidence of AT. No direct comparison between AT risk in RF and CB ablation has been made.

Atrial Arrhythmias in Obstructive Sleep Apnea: Underlying Mechanisms and Implications in the Clinical Setting

Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive interruption of ventilation during sleep caused by recurrent upper airway collapse, which leads to intermittent hypoxia. The disorder is commonly undiagnosed despite its relationship with substantial cardiovascular morbidity and mortality. Moreover, the effects of the disorder appear to be particularly dangerous in young subjects. In the last decade, substantial clinical evidence has identified OSA as independent risk factor for both bradyarrhythmias and tachyarrhythmias. To date the mechanisms leading to such arrhythmias have not been completely understood. However, recent data from animal models and new molecular analyses have increased our knowledge of the field, which might lead to future improvement in current therapeutic strategies mainly based on continuous positive airway pressure. This paper aims at providing readers a brief and specific revision of current knowledge about the mechanisms underlying atrial arrhythmias in OSA and their clinical and therapeutic implications.