Role Of Prophylactic Magnesium Supplementation in Prevention of Postoperative Atrial Fibrillation in Patients Undergoing Coronary Artery Bypass Grafting: A Meta-analysis of 23 Randomized Controlled Trials (Poster).

Background Several randomized clinical trials have evaluated the efficacy of prophylactic magnesium (Mg) supplementation in prevention of post-operative atrial fibrillation (POAF) in patients undergoing cardiac artery bypass grafting (CABG). We aim to determine the role of prophylactic Mg in 3 settings (intraoperative, postoperative, intraoperative + postoperative) in prevention of POAF. Methods A systemic literature search was performed (until October 20, 2015) using PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials to identify trials evaluating Mg supplementation post CABG. Primary outcome of our study was reduction in the POAF. For each study, the incidence of atrial fibrillation in both the intervention and placebo groups was extracted to calculate odd ratio and 95% confidence intervals (CIs). Results We included a total of 2,973 participants (1,471 in the Mg group and 1,502 in the placebo group) enrolled in 23 randomized controlled trials. By using random-effects models, pooled analysis demonstrated no significant reduction in POAF (OR 0.81; 95% CI, 0.64-1.02; p = 0.08) in Mg group as compared to placebo. However, there was reduction in POAF in the group that received prophylactic Mg postoperatively (OR 0.66; 95% CI 0.44-0.99; p = 0.04) with no significant heterogeneity. Number needed to treat in our study = 13 (95% CI 7.04-81.34). Conclusions Prophylactic postoperative Mg supplementation resulted in a lower incidence of POAF in patients undergoing CABG

Pre-rift evolution of Malawian high-grade basement rocks

There is some controversy in terms of the basement geology of Malawi which ultimately stems from the overall lack of metamorphic studies conducted in the area. The geological complexity of Malawi comes from that fact that it sits at the intersection of three major orogenic belts: The Palaeoproterozoic Ubendian Belt, Mesoproterozoic Kibaran/Irumide Belt, and Pan African Mozambique Belt. Its complexity makes it difficult to unravel, especially in terms of identifying features of older orogenic events which have already experienced multiple metamorphic overprinting from subsequent events. This thesis provides a more detailed pre-rift evolution of the Malawian basement rocks by reporting ages and P-T conditions from four localities surrounding Lake Malawi, namely Chilumba, Mlowe, Maganga, and Mangochi. Results reveal that at 1985-1974 Ma, garnet-cordierite granulites were equilibrated under conditions of 760°C at 4.5-5 kbar possibly as a result of subduction-related magmatism. Subsequently, at 1100 Ma, charnockites were emplaced and metamorphosed under peak conditions of 770-780°C at 4.3-6 kbar due to Kibaran-age magmatic underplating. Remnants of the Irumide/Kibaran Orogeny is relatively scarce throughout Malawi and although the Mangochi charnockites were emplaced during Kibaran-age tectonism, it also experienced at least two different metamorphic events thereafter. The first occurred either during early stages of the East African orogen or Rodinia break-up at 900-800 Ma while the second occurred during the late stages of the East African orogen at 650-600 Ma. Possible remnants of the Kuunga Orogeny are recorded in Chilumba and Maganga as an amphibolite facies metamorphic event which took place around 570 Ma under peak conditions of roughly 660-670°C at 6-8 kbar. Findings of this study have not only provided a more detailed metamorphic history of Malawi but also paved way for future studies in the area to further explore why similar rocks found in such close proximity to each other preserve vastly different tectonic environments

Transcatheter Aortic Valve Replacement is Associated With a Higher Rate of Permanent Pacemaker Implantation Compared to Surgical Aortic Valve Replacement: A Propensity Matched Analysis (Poster).

Background Occurrence of conduction abnormalities requiring permanent pacemaker implantation (PPI) is a serious complication after both transcatheter (TAVR) & surgical (SAVR) aortic valve replacement. Methods Nationwide Inpatient Sample was queried from August 2011 to December 2012 using ICD-9 codes 35.05 & 35.06 for TAVR and 35.21 & 35.22 for SAVR. Patients undergoing other valve surgeries, bypass grafting & those with prior pacemakers or defibrillators were excluded. Propensity matching was performed (1:1) to match TAVR & SAVR cohorts on age, gender, right bundle branch block (RBBB), first degree AV block, bifascicular or trifascicular block, hospital region, teaching hospital status & hospital bed size. Logistic regression was performed to identify predictors of PPI. Differences in the two cohorts were tested using chi-square test. Results Total 2,990 patients (1,495 in TAVR group & 1,495 in SAVR group) were included, with mean age 80.2 +/- 9.0 years, 50.4% females & 83.2% Caucasians. RBBB (OR 2.3, 95% CI 1.4-4.0, p = 0.002) & bifascicular or trifascicular block (OR 6.9, 95% CI 2.8-17.0, p Conclusions PPI rates are higher after TAVR (with predominantly balloon expandable valves) compared to SAVR, after matching on demographic, EKG & hospital characteristics. This suggests greater damage to cardiac conduction system with TAVR compared to SAVR

Cryoballoon versus Radiofrequency Ablation for Atrial Fibrillation: A Meta-analysis of 16 Clinical Trials.

Introduction: We aimed to study the procedural characteristics, efficacy and safety of cryoballoon ablation (CBA) versus radiofrequency ablation (RFA) for catheter ablation of paroxysmal atrial fibrillation (AF). Methods: A systematic literature search was performed using PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials to clinical trials comparing CBA and RFA for AF. Outcomes were evaluated for efficacy, procedure characteristics and safety. For each study, odd ratio (OR) and 95% confidence intervals (CIs) were calculated for endpoints for both approaches. Results: We analyzed a total of 9,957 participants (3,369 in the CBA and 6,588 in RFA group) enrolled in 16 clinical trials. No significant difference was observed between CBA and RFA with regards to freedom from atrial arrhythmia at 12-months, recurrent atrial arrhythmias or repeat catheter ablation. CBA group had a significantly higher transient phrenic nerve injury (OR 14.19, 95% CI: 6.92-29.10;

Exercise Training in Patients with Heart Failure and Preserved Ejection Fraction: A Meta-analysis of Randomized Control Trials.

BACKGROUND: -Heart failure with preserved ejection fraction (HFPEF) is common and characterized by exercise intolerance and lack of proven effective therapies. Exercise training has been shown to be effective in improving cardiorespiratory fitness (CRF) in patients with systolic heart failure. In this meta-analysis, we aim to evaluate the effects of exercise training on CRF, quality of life and diastolic function in patients with HFPEF. METHODS AND RESULTS: -Randomized controlled clinical trials that evaluated the efficacy of exercise training in patients with HFPEF were included in this meta-analysis. Primary outcome of the study was change in CRF (measured as change in peak oxygen uptake). Impact of exercise training on quality of life (estimated using Minnesota living with heart failure score), left ventricular systolic and diastolic function was also assessed. The study included 276 patients that were enrolled in 6 randomized controlled trials. In the pooled data analysis, HFPEF patients undergoing exercise training had significantly improved CRF (L/min) (Mean difference: 2.72; 95% CI: 1.79 to 3.65) and quality of life (Mean difference: -3.97; 95% CI: -7.21 to -0.72) as compared with the control group. However, no significant change was observed in the systolic function [Ejection Fraction - Weighted Mean difference (WMD): 1.26; 95% CI: -0.13% to 2.66%] or diastolic function [E/A - WMD: 0.08; 95% CI:-0.01 to 0.16] with exercise training in HFPEF patients. CONCLUSIONS: -Exercise training in patients with HFPEF is associated with an improvement in CRF and quality of life without significant changes in left ventricular systolic or diastolic function