Vitamin C for preventing atrial fibrillation in high risk patients : a systematic review and meta-analysis

Background: Atrial fibrillation (AF), a common arrhythmia contributing substantially to cardiac morbidity, is associated with oxidative stress and, being an antioxidant, vitamin C might influence it. Methods: We searched the Cochrane CENTRAL Register, MEDLINE, and Scopus databases for randomised trials on vitamin C that measured AF as an outcome in high risk patients. The two authors independently assessed the trials for inclusion, assessed the risk of bias, and extracted data. We pooled selected trials using the Mantel-Haenszel method for the risk ratio (RR) and the inverse variance weighting for the effects on continuous outcomes. Results: We identified 15 trials about preventing AF in high-risk patients, with 2050 subjects. Fourteen trials examined post-operative AF (POAF) in cardiac surgery patients and one examined the recurrence of AF in cardioversion patients. Five trials were carried out in the USA, five in Iran, three in Greece, one in Slovenia and one in Russia. There was significant heterogeneity in the effect of vitamin C in preventing AF. In 5 trials carried out in the USA, vitamin C did not prevent POAF with RR = 1.04 (95% CI: 0.86-1.27). In nine POAF trials conducted outside of the USA, vitamin C decreased its incidence with RR = 0.56 (95% CI: 0.47-0.67). In the single cardioversion trial carried out in Greece, vitamin C decreased the risk of AF recurrence by RR = 0.13 (95% CI: 0.02-0.92). In the non-US cardiac surgery trials, vitamin C decreased the length of hospital stay by 12.6% (95% CI 8.4-16.8%) and intensive care unit (ICU) stay by 8.0% (95% CI 3.0-13.0%). The US trials found no effect on hospital stay and ICU stay. No adverse effects from vitamin C were reported in the 15 trials. Conclusions: Our meta-analysis indicates that vitamin C may prevent post-operative atrial fibrillation in some countries outside of the USA, and it may also shorten the duration of hospital stay and ICU stay of cardiac surgery patients. Vitamin C is an essential nutrient that is safe and inexpensive. Further research is needed to determine the optimal dosage protocol and to identify the patient groups that benefit the most.Peer reviewe

Cardiopulmonary Resuscitation in Adults Over 80 : Outcome and the Perception of Appropriateness by Clinicians

OBJECTIVES To determine the prevalence of clinician perception of inappropriate cardiopulmonary resuscitation (CPR) regarding the last out-of-hospital cardiac arrest (OHCA) encountered in an adult 80 years or older and its relationship to patient outcome. DESIGN Subanalysis of an international multicenter cross-sectional survey (REAPPROPRIATE). SETTING Out-of-hospital CPR attempts registered in Europe, Israel, Japan, and the United States in adults 80 years or older. PARTICIPANTS A total of 611 clinicians of whom 176 (28.8%) were doctors, 123 (20.1%) were nurses, and 312 (51.1%) were emergency medical technicians/paramedics. RESULTS AND MEASUREMENTS The last CPR attempt among patients 80 years or older was perceived as appropriate by 320 (52.4%) of the clinicians; 178 (29.1%) were uncertain about the appropriateness, and 113 (18.5%) perceived the CPR attempt as inappropriate. The survival to hospital discharge for the "appropriate" subgroup was 8 of 265 (3.0%), 1 of 164 (.6%) in the "uncertain" subgroup, and 2 of 107 (1.9%) in the "inappropriate" subgroup (P = .23); 503 of 564 (89.2%) CPR attempts involved non-shockable rhythms. CPR attempts in nursing homes accounted for 124 of 590 (21.0%) of the patients and were perceived as appropriate by 44 (35.5%) of the clinicians; 45 (36.3%) were uncertain about the appropriateness; and 35 (28.2%) perceived the CPR attempt as inappropriate. The survival to hospital discharge for the nursing home patients was 0 of 107 (0%); 104 of 111 (93.7%) CPR attempts involved non-shockable rhythms. Overall, 36 of 543 (6.6%) CPR attempts were undertaken despite a known written do not attempt resuscitation decision; 14 of 36 (38.9%) clinicians considered this appropriate, 9 of 36 (25.0%) were uncertain about its appropriateness, and 13 of 36 (36.1%) considered this inappropriate. CONCLUSION Our findings show that despite generally poor outcomes for older patients undergoing CPR, many emergency clinicians do not consider these attempts at resuscitation to be inappropriate. A professional and societal debate is urgently needed to ensure that first we do not harm older patients by futile CPR attempts.Peer reviewe