Myth-Bust – Can We Give Nitrates to RV Infarction?

March 15, 2023

Written by Jonathan Brewer

Spoon Feed
New evidence has demonstrated that previous dogma to withhold nitrates from patients with right ventricular myocardial infarction (RVMI) may be incorrect.

Why does this matter?
Current American Heart Association (AHA) and European Society of Cardiology (ESC) guidelines recommend that when RVMI is present, patients should not be administered nitrates due to the risk of decreasing preload and subsequent hemodynamic instability. This has long been taught, but is it correct?

Do we pump the brakes on nitrates?
This systematic review included five studies (n=1,113 patients), with outcomes including hemodynamics (hypotension defined as < 100 mmHg in some studies, < 90 mmHg in another), GCS, syncope, cardiac arrest, and death. Two of the studies allowed for meta-analysis; when sublingual nitroglycerin was administered at a dose of 400 μg (n = 1,050), there was no statistically significant difference in relative risk in patients with combined inferior and RVMI: RR 1.31 (95%CI 0.81 to 2.12, p = 0.27), with an absolute effect of 3 adverse events per 100 treatments.

Interestingly enough, the initial 1989 cohort study – that both the AHA and ESC guidelines are based on – consisted of 40 patients that received unknown doses and routes of administration of nitroglycerin (a large limitation). While this early paper demonstrated a risk ratio of 4.06 (95%CI 1.83 – 8.98), its limitations make practical application difficult. Therefore, this meta-analysis suggests that, while further studies are needed, there is not a statistically significant difference in the rate of nitrate-induced adverse events between various types of MI.

Source
Adverse events from nitrate administration during right ventricular myocardial infarction: a systematic review and meta-analysis. Emerg Med J. 2023 Feb;40(2):108-113. doi: 10.1136/emermed-2021-212294. Epub 2022 Sep 30.