The median effective dose from cardiac CT with standard filtered back-projection was comparable with the effective dose from invasive coronary angiography, even with application of the most contemporary ICRP tissue weightings and use of cardiac specific volumes. Cardiac CT scanning incorporating iterative reconstruction resulted in a significant reduction in the effective dose.
BACKGROUND Patients with atrial fibrillation (AF) often have sleep apnea (SA), but diagnosis of SA with polysomnography is costly. SA monitoring is a pacemaker feature that measures respiratory disturbance index, the sum of abnormal respiratory events divided by sleep duration. OBJECTIVE The purpose of this study was to evaluate the incidence and severity of SA and its association with AF in an unselected population fitted with pacemakers. METHODS RESPIRE (REgistry of Sleep APnea monItoring and Atrial Fibrillation in pacemakeR patients) was a multicenter, international, observational, open-label study following adult subjects for 18 months after implantation with an SA monitoring-enabled dual-chamber pacemaker. Severe SA was defined as average respiratory disturbance index 20 from implantation to follow-up visit. The first co-primary end point was the difference in significant AF (cumulative AF episodes lasting 24 hours over 2 consecutive days) between subjects with severe and those nonsevere SA at 12 months in the full analysis set (N 5 553). The second co-primary end point was the rate of major serious adverse events at 18 months in the modified intention-to-treat set (N 5 1024). RESULTS Severe SA was detected in 31.1% (172 of 553). A higher incidence of significant AF was reported in patients with severe SA than in patients with nonsevere SA (25.0% vs 13.9%; difference 11.1%; 95% confidence interval 3.7%-18.4%; P 5 .002). Significant AF increased with time in both groups, but at a faster rate in the severe SA group. No intergroup difference in the overall rate of major serious adverse events was observed (P 5 .065). CONCLUSION SA screening over 12 months identified severe SA in almost one-third of unselected patients fitted with pacemakers. Severe SA was associated with a higher incidence of significant AF.
IntroductionIn atrial fibrillation (AF) dose-adjusted warfarin reduces the risk of stroke by almost 2/3, but patients with better therapeutic international normalised ratio (INR) derive most benefit. The new NICE guidance from August 2014 for non-valvular AF recommended consideration of novel oral anticoagulants (NOAC) if time in therapeutic range (TTR) with warfarin <65%.We investigated the success of anticoagulation in our patients with AF with reference to the NICE guidance, and compared it with the published literature, and our cohort of patients with mechanical valves.Materials and MethodsThrough the anticoagulation clinic we identified all patients on warfarin for the entire duration of 2012 who had taken warfarin for >6 months before 01/01/2012. We identified 2737 patients on warfarin for AF and 58 patients for prosthetic heart valve (PHV) in the aortic or mitral position. We excluded patients with elective/emergency hospital admissions not relating to anticoagulation and analysed TTR for 51 patients with PHV and a randomly selected a sample of 102 patients with AF. The target INR was 2.5 for AF and 3.5 for all PHV. Using the Rosendaal method we calculated the TTR in the two groups for all 365 days in 2012.ResultsThe results are shown in Table 1. Patients with AF had a better mean TTR (76%) than patients with PHV (61%) which could be explained by the difference in INR targets in the two groups. The patients with AF had an average of 11.9 INR tests per year while the patients with PHV had an average of 26.2 INR tests per year.Abstract 60 Table 1Time in therapeutic range in patients with AF and prosthetic heart valvesIndicationTotalMean age (years)Average number of tests/patientAverage number of tests in range/patientAverage% of tests in range/patientAverage number of days in range/patientMean TTRAtrial Fibrillation10279.211.97.971.7%279.076.4%Mechanical heart valve516826.212.551.2%224.461.4%DiscusionOur AF patients had the same therapeutic target as the published NOAC trials i.e. INR target 2.5; yet our cohort showed significantly higher TTR (76%) than the NOAC studies (55–65%) and was comparable to the Swedish registry as shown in Table 2. Patients with PHV showed an inferior TTR (61.4%) and required more INR tests (26.2 vs 11.9), however a different anticoagulation target meant that the two groups could not be directly compared.Abstract 60 Table 2Table comparing the TTR seen in our AF cohort and that of published literatureNo of patients on warfarinF/U timeTTRCompared with our cohort Chi Sq with yates correction p value <0.05 were considered significantDabigatran602224 months0.0124*Rivaroxaban713323 months0.0001*Apixaban908122 months0.0038*Edoxaban703634 months0.0209*Auricula - Whole study1839112 months0.9490- AF cohort only1177012 months0.9945*indicates a statistically significant differenceConclusionWe conclude that in our AF population a target INR=2 is safely achieved with very good mean TTR (76%) and relatively few INR tests (<1 per month). This compares very favourably with the TTR seen in the NOAC...
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