The review of 15 randomised trials involving more than 2,000 people pulled together data from research that tested the effects of oral or intravenous (IV) vitamin C given after heart surgery.
Led by Harri Hemilä from the University of Helsinki, the team noted that atrial fibrillation is a common cardiac rhythm disturbance that can lead to severe consequences including stroke and heart failure.
This can be triggered by stressful conditions, and around 30% of patients undergoing cardiac operations suffer from post-operative AF, they noted.
Writing in BMC Cardiovascular Disorders the team reported that oral administration of vitamin C decreased the occurrence of post-operative AF by 73%, while IV administration decreased it by 36%.
However, when it came to length of hospital stay the results were flipped, with oral administration shortening average stay by only 7% (0.4 days), whereas IV decreased it by 16% (1.5 days).
Thus, the effect of intravenous vitamin C administration was greater for the length of hospital stay, but less for the occurrence of post-operative AF.
Country-specific
When the data was split by geographic and socio-economic demographics the team also found significant differences in trial results; those carried out in Iran and Greece indicated that vitamin C may have strong prevention effects, while studies performed in the USA found no benefit.
AS a result, the team said trials in less wealthy countries should be carried out to optimise the protocol for vitamin C administration and to determine which patient groups get the most benefit, for example, by examining vitamin C status before the cardiac operation or cardioversion.
"Vitamin C is a safe low-cost essential nutrient,” said the researchers. “Given the consistent evidence from the less wealthy countries, vitamin C might be administered to cardiac surgery patients, although further studies are needed to find out optimal protocols for its administration.”
“However, there seems to be no rationale for further study of unselected patients in wealthy countries, but the effects of vitamin C for patients who have a particularly low documented level of vitamin C might still be worthwhile."
Source: BMC Cardiovascular Disorders
Published online, Open Access, doi: 10.1186/s12872-017-0478-5
“Vitamin C for preventing atrial fibrillation in high risk patients: a systematic review and meta-analysis”
Authors: Harri Hemilä