Why do myocardial infarctions (MIs) cause nausea and vomiting?

From the Guidelines

Myocardial infarctions (MIs) cause nausea and vomiting primarily due to autonomic nervous system activation during cardiac distress, as evidenced by the most recent and highest quality study 1. When heart tissue is damaged during an MI, pain signals and stress responses trigger the vagus nerve, which innervates both the heart and the digestive tract. This vagal stimulation leads to increased parasympathetic activity, causing gastric distress symptoms like nausea and vomiting. Some key points to consider include:

• The body releases stress hormones such as catecholamines during an MI, which can disrupt normal digestive function and contribute to these symptoms 1.
• The referred pain phenomenon also plays a role, as cardiac pain can be perceived in other areas including the abdomen, confusing the brain's interpretation of distress signals.
• These gastrointestinal symptoms are particularly common in inferior wall MIs because the same vagal nerve fibers supply both the inferior heart wall and the digestive organs.
• It's essential to recognize that nausea and vomiting can sometimes be the predominant symptoms of an MI, especially in women, elderly patients, and those with diabetes, potentially leading to delayed diagnosis if mistaken for simple indigestion or stomach issues 1. Key considerations for diagnosis and treatment include:
• Assessing associated symptoms such as dyspnea, diaphoresis, and nausea, which are more frequent in women with acute myocardial infarction 1.
• Obtaining a stat ECG for patients with symptoms such as chest pain, severe epigastric pain, or unexplained indigestion, belching, or epigastric pain 1.
• Taking a brief, targeted medical history to assess current or past history of CAD, angina, or MI, as well as risk factors such as smoking, hyperlipidemia, and hypertension 1.

From the Research

Myocardial Infarction and Associated Symptoms

• Myocardial infarctions (MIs) are often accompanied by symptoms such as nausea and vomiting, but the relationship between these symptoms and the location or size of the infarct is not fully understood.
• Studies have investigated the incidence of nausea and vomiting in patients with acute myocardial infarction, with some suggesting a possible link to infarct size rather than location 2, 3.

Relation to Infarct Location

• Research has shown that nausea and vomiting are common presenting symptoms in patients with either inferior or anterior wall AMI, but their frequency is unrelated to the infarct location 2.
• Another study found that cardiogenic nausea and vomiting are associated with larger myocardial infarctions, but do not suggest infarcts in a particular location 3.

Predictive Value of Nausea and Vomiting

• Nausea or vomiting has been found to be a good predictor of myocardial infarction, with the odds of having an infarction being 3.14 times greater for patients with these symptoms than for those without them 3.
• However, the presence of nausea and vomiting does not appear to be associated with specific electrocardiographic patterns of acute myocardial infarction, such as Q wave versus non-Q wave or localization 4.

Treatment and Management

• The management of patients with acute myocardial infarction has evolved over time, with the use of various treatments such as beta-blockers, nitrates, aspirin, and thrombolytic agents becoming more widespread 5, 6.
• These treatments have been shown to reduce mortality rates and improve outcomes in patients with uncomplicated myocardial infarction, but the relationship between these treatments and the incidence of nausea and vomiting is not well understood.