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Health See other Health Articles Title: Cardioversion for Atrial Fibrillation May Improve Cerebral Blood Flow, Brain Perfusion Topic Alert Receive an email from Medscape whenever new articles on this topic are available. Personal Alert Add Atrial Fibrillation to My Topic Alert Related Drugs & Diseases Atrial Fibrillation Synchronized Electrical Cardioversion Defibrillation and Cardioversion MILAN, ITALY — New research has shed light on a mechanism other than multiple infarcts that may contribute to the association between between atrial fibrillation (AF) and decreased brain function[1]. Analysis of the first 26 completers of an ongoing study of patients with AF at baseline showed, through two validated measures, that those who went into sinus rhythm after undergoing cardioversion had significantly improved cerebral blood flow (CBF) and brain perfusion vs those with continued AF. In addition, brain perfusion after the procedure increased in both gray matter and whole brain scans. "What surprised me the most was that the results were so consistent with our theories," lead author Dr Maranna Gardarsdottir (National University Hospital of Iceland, Reykjavik) told heartwire from Medscape. "When patients are in afib, they seem to have reduced blood flow, which is restored after cardioversion," she added. "Altered blood flow may help explain why atrial fibrillation has been associated with cognitive decline." Gardarsdottir presented her findings here at the European Heart Rhythm Association (EHRA) EUROPACE-CARDIOSTIM 2015 meeting. Postprocedure Improvements Past research has shown that lower cerebral perfusion may contribute to the development of neurodegenerative diseases. In addition, a large retrospective study published in Stroke in 2013[2] showed significant links between AF and reductions in both brain volume and cognition, even after taking into account cerebral infarcts, noted Gardarsdottir. For the current study, her investigative team sought to extend these findings by examining whether cardioversion could advantageously affect brain perfusion and/or CBF. Dr Maranna Gardarsdottir They used phase-contrast MRI to measure total CBF and used arterial spin labeling (ASD) to measure brain perfusion. The two measures were conducted before and 10 weeks after elective cardioversion to treat the participants' AF. Right before the second MRI, ECG was used to verify whether each patient still had AF or whether they were in sinus rhythm. Analysis of 26 patients (77% men, mean age 62 years) showed that CBF increased significantly from a mean of 557.4 mL/min to 627.1 mL/min (P=0.01) for the group that was in sinus rhythm at the second MRI (n=17). In addition, their whole-brain perfusion increased from 35.6 mL/100 g/min to 40.8 mL/100 g/min (P<0.01) and their gray-matter brain perfusion increased from 39.3 mL/100 g/min to 45.7 mL/100 g/min (P<0.001). Although both CBF and BP decreased slightly for the group with continued AF at second MRI, these changes were not considered to be significant. Gardarsdottir said that the investigators hope to next look at a treatment-outcomes study that measures brain function, brain volume, and CBF to see "if there may be some way to detect early signs of brain-volume deterioration so that we can stop the process. But the question is: where do we need to stop it? Do we need to treat the patients really early?" Hot Topic Comoderator Dr Jeff Healey (McMaster University, Hamilton, ON) told heartwire that cognitive decline in AF is a "hot topic," and the study looked at issues surrounding that in a way he hadn't considered before. "It had a small number of patients but adds a lot to the discussion of this issue. It already generated a lot of discussion at the presentation," he said. "The size was actually adequate for showing what they wanted to show, which was a change in cerebral blood flow. Now, the next obvious step would be to show if this really is coordinated with cognitive decline." Gardarsdottir and Healey reported no relevant financial relationships. Latest in Cardiology CARDIO-FIT: Structured Exercise May Lower AF Recurrence BRIDGE: No Benefit From Perioperative LMWH in Patients With AF Related Links AF Detected by Monitoring Blood Flow in Human Face Atrial fibrillation and cognitive decline Silent Atrial Fibrillation Increases Stroke Risk Poster Comment: normal sinus rhythm (NSR) Etymology: L, norma, rule, sinus, hollow; Gk, rhythmos the normal heartbeat initiated by the pacemaker in the sinus node, with a heart rate of 60 to 100 beats/min. sinus node, - a cluster of hundreds of cells located in the right atrial wall of the heart, near the opening of the superior vena cava. It comprises a knot of modified heart muscle that generates impulses that travel swiftly throughout the muscle fibers of both atria, causing them to contract. Specialized pacemaker cells in the node have an intrinsic rhythm that is independent of any stimulation by nerve impulses from the brain and the spinal cord. Slender fusiform cells making up the sinoatrial node are largely filled with sarcoplasm but contain a few striated fibrillae. The cells are irregularly grouped together and, at the edge of the node, merge with the atrial musculature. The sinoatrial node will normally "fire" at a rhythmic rate of 70-75 beats/min. If the node fails to generate an impulse, pacemaker function will shift to another excitable component of the cardiac conduction system, such as the atrioventricular node or Purkinje's fibers. Certain hormones and various autonomic impulses can affect the sinoatrial node and cause it to "fire" faster, such as during strenuous physical activity. During a lifetime of 70 years the node generates about 2 billion impulses. Surgical implantation of an artificial pacemaker is a common procedure for individuals suffering from a defective sinoatrial node. Also called Keith-Flack node, Keith's bundle, pacemaker, sinoatrial node, sinus pacemaker. Compare atrioventricular node, Purkinje's network. Post Comment Private Reply Ignore Thread
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