Short periods of cerebral ischaemia during ventricular defibrillation testing may be associated with neuropsychological impairment. However, the impact of out-of-hospital ventricular fibrillation (VF) converted by implantable cardioverter-defibrillator (ICD) shock on cognitive functioning is unknown. To assess the impact of out-of-hospital VF converted by ICD shock on cognitive functioning. The study included 52 primary prevention ICD recipients. Patients with a history of stroke or other neurological impairment, previous head injury and individuals unable to see or speak to complete neuropsychological tests were not included.Initially, a Mini-Mental State Examination was performed in all patients and one patient with a result below 24 points was excluded from the study. The cognitive battery consisted of four tests (six measurements): 1) the Digit Span subtest of Wechsler Adult Intelligence Scale-Revised; 2) the Digit Symbol subtest of Wechsler Adult Intelligence Scale-Revised; 3) the Halstead-Reitan Trail-Making Test A and B; and 4) the Ruff Figural Fluency Test. The mean time from ICD implantation to cognitive assessment was 26 months. During this period, 15 appropriate shocks for VF were observed in seven (14%) patients. The patients with appropriate ICD therapy were significantly worse in two out of the six neuropsychological measurements and had a significantly lower aggregate result. In multivariate linear regression analysis, defibrillation therapy was an independent factor of poor cognitive functioning, along with age and education. Short periods of out-of-hospital VF converted by ICD are associated with cognitive impairment in the recipients of primary prevention ICD.

Background: Several clinical and experimental studies have shown that unnecessary right ventricular pacing in sinus node disease can be detrimental. Inter- and intra-ventricular asyn­chrony imposed by right ventricular pacing may cause reduction in contractility and relaxation of left ventricle, worsening mitral regurgitation, regional redistribution of myocardial perfusion and oxygen consumption, and asymmetrical hypertrophy of left ventricular wall. In some patients, sinus node disease coexists with impaired atrioventricular conduction. The optimal pacing mode in this population is not determined. Minimizing right ventricular pacing can preserve inter- and intra-ventricular synchrony. On the other hand, longer atrioventricular delay may cause atrioventricular asynchrony. The aim of this study was to prospectively assess the impact of minimizing right ventricular pacing in patients with DDD pacemaker implanted for sinus node disease and prolonged PQ interval on exercise capacity, cardiac function and quality of life. Methods: The study enrolled 50 consecutive patients with prolonged PQ interval who were implanted with DDD pacemaker because of sinus node disease. Each patient was treated alternately with 2 pacing modes in random order for 4-month periods: conventional dualchamber pacing and dual-chamber minimal ventricular pacing (prolonged atrioventricular delay). At the end of each phase the following tests were performed: cardiopulmonary exercise testing, echocardiographic evaluation and quality of life assessment (SF36). Results: There was no significant relationship between pacing mode and cardiopulmonary parameters, echocardiographic parameters and quality of life. Conclusions: Sequential atrioventricular pacing may be a reasonable choice for treating patients with sinus node disease and prolonged PQ interval. Background: Several clinical and experimental studies have shown that unnecessary right ventricular pacing in sinus node disease can be detrimental. Inter- and intra-ventricular asyn­chrony imposed by right ventricular pacing may cause reduction in contractility and relaxation of left ventricle, worsening mitral regurgitation, regional redistribution of myocardial perfusion and oxygen consumption, and asymmetrical hypertrophy of left ventricular wall. In some patients, sinus node disease coexists with impaired atrioventricular conduction. The optimal pacing mode in this population is not determined. Minimizing right ventricular pacing can preserve inter- and intra-ventricular synchrony. On the other hand, longer atrioventricular delay may cause atrioventricular asynchrony. The aim of this study was to prospectively assess the impact of minimizing right ventricular pacing in patients with DDD pacemaker implanted for sinus node disease and prolonged PQ interval on exercise capacity, cardiac function and quality of life. Methods: The study enrolled 50 consecutive patients with prolonged PQ interval who were implanted with DDD pacemaker because of sinus node disease. Each patient was treated alternately with 2 pacing modes in random order for 4-month periods: conventional dualchamber pacing and dual-chamber minimal ventricular pacing (prolonged atrioventricular delay). At the end of each phase the following tests were performed: cardiopulmonary exercise testing, echocardiographic evaluation and quality of life assessment (SF36). Results: There was no significant relationship between pacing mode and cardiopulmonary parameters, echocardiographic parameters and quality of life. Conclusions: Sequential atrioventricular pacing may be a reasonable choice for treating patients with sinus node disease and prolonged PQ interval.