ABSTRACT
BACKGROUND: Although data about circadian variation of myocardial infarction (MI) in western populations reveal morning peak between 06:00 and 12:00 hours, differences have been reported in different regions of the world and ethnic groups. We aimed to evaluate circadian variation of MI in a Turkish cohort. METHODS: A total of 476 patients (mean age 56.7 +/- 11.7; 80% men) with acute st elevation MI were included into the study. Patients were categorised into four 6-h increments (00:01-06:00; 06:01-12:00; 12:01-18:00 and 18:01-24:00 hours). RESULTS: Onset of MI exhibited significant circadian variation among four time periods (p < 0.001), demonstrating afternoon peak (between 12:01 and 18:00 hours) and trough between 00:01 and 06:00 hours. Incidence of MI between 12:01 and 18:00 hours was significantly higher when compared with other three 6-h periods (p = 0.001). Incidence of MI between 00:01 and 06:00 hours was significantly lower when compared with other three 6-h periods (p = 0.001). Incidence of MI between 12:01 and 18:00 hours was 1.64 times that of average frequency of the remaining 18:00 hours of the day and 2.3 times that of frequency between 00:01 and 06:00 hours. When analysed for the subgroups of the study sample, only smoking blunted the afternoon peak. CONCLUSIONS: Instead of early morning peak in western countries, there is afternoon predominance in circadian variation of MI in a Turkish cohort. It may be related with genetic and/or demographic characteristics of Turkish population. Further studies are required to determine underlying pathophysiological mechanisms causing these differences in chronobiology of MI among populations.
Subject(s)
Myocardial Infarction/epidemiology , Periodicity , Aged , Circadian Rhythm , Epidemiologic Methods , Female , Humans , Incidence , Male , Middle Aged , Smoking , Time Factors , Turkey/epidemiologyABSTRACT
Catheter ablation, notably the electric isolation of pulmonary veins, has become a well-established therapeutic approach in symptomatic atrial fibrillation. The NavX navigation system has been described to facilitate pulmonary vein isolation in patients with AF. EnSite NavX (Endocardial Solutions, St. Jude Medical, Inc., St. Paul, MN, USA) is a novel navigation system that measures the local voltage on every standard intra-cardiac electrode and calculates the electrode position in three-dimensional (3D) space. Any individual electrode of each catheter in 3D-space can be displayed and labelled individually. The geometry of any cardiac chamber can be reconstructed and additional information, e.g. electrical activation spreading, can be displayed colour coded on the surface. Recent studies investigating the possible advantages of this system in the ablation of persistent or paroxysmal atrial fibrillation are summarized. All reports showed a significant reduction in fluoroscopy and procedure time by the use of the NavX system compared to conventional fluoroscopic catheter guidance. This benefit can be obtained with simple visualisation of all intracardiac catheters alone or with additional reconstruction of the left atrium and pulmonary veins.
Subject(s)
Atrial Fibrillation/diagnosis , Atrial Fibrillation/surgery , Body Surface Potential Mapping/instrumentation , Catheter Ablation/methods , Imaging, Three-Dimensional/instrumentation , Surgery, Computer-Assisted/instrumentation , Equipment Design , Equipment Failure Analysis , Humans , Imaging, Three-Dimensional/methods , Surgery, Computer-Assisted/methods , User-Computer InterfaceABSTRACT
Electrophysiological stimulation and ablation is currently performed with manually deflectable catheters of different lengths and curves. Disadvantages of conventional therapy are catheter stiffness, limited local stability, risk of dislocation or perforation, and reduced tissue contact in regions with difficult access. Fluoroscopy to control catheter movement and position may require substantial radiation times. Magnetic navigation was first applied for right heart catherization in congenital heart disease in 1991; the first electrophysiological application took place in 2003. Today, an ablation electrode with small magnets is aligned in the patient's heart by two external magnets positioned at both sides of the thorax. Antegrade and retrograde movement of the distal catheter tip are performed via an external device on the patient's thigh. Three-dimensional MRI scans acquired before intervention can be merged with electroanatomical reconstruction, leading to further reductions of radiation burden. During treatment of supraventricular tachyarrhythmias high local precision of magnetically guided catheters, good local stability, and a substantially reduced radiation time have been reported. First applications in ventricular tachyarrhythmias and complex congenital cardiac defects indicate a comparable effect. Limitations of this therapy are the application in left atrial procedures (open irrigated ablation catheters not yet available), difficult transaortic retrograde approach (high lead flexibility), and the considerable costs. Magnet-assisted navigation is feasible during percutaneous coronary interventions of tortuous coronary arteries and in positioning guidewires in coronary sinus side branches for resynchronisation therapy. Future applications will be complex left atrial procedures, magnetically guided cardiac stem cell therapy, local drug application, and extracardiac vessel therapy.