Category: Cardiac Ischemia

Nitro or No Nitro when Pain Free


The answer to your question will depend on the clinical presentation of your patient.

When you are suspecting your patient is presenting with cardiac ischemia, it is appropriate to consider nitroglycerin. Nitroglycerine is considered the first-line symptom relief for the treatment of acute symptoms associated to cardiac ischemia but has not demonstrated changes in a patient’s morbidity/mortality like ASA.

Nitroglycerin is not an analgesic; rather, it can assist in managing or relieving a variety of symptoms that can present with cardiac ischemia and that are not exclusive to pain, pressure or discomfort. the primary anti-ischemic effect of nitrates is to decrease myocardial oxygen demand by producing systemic vasodilation more than coronary vasodilation. Administering nitro may lead to increased perfusion of ischemic zones.

Potential mechanisms by which nitrates can relieve cardiac ischemia symptoms include:
• Dilatation of large coronary arteries and arterioles.
• Dilatation of the venous system.
• Systemic arterial dilatation.
• Enhanced collateral blood flow.

The typical clinical presentation of cardiac ischemia other than pain, discomfort or pressure can include:
• Shortness of breath
• Gastric features: belching, nausea, indigestion, and/or vomiting,
• Diaphoresis or clamminess
• Dizziness or light-headedness
• Fatigue

Atypical features include:
• Sharp or stabbing pain
• Epigastric pain or discomfort
• Palpitations
• Syncope

(Reeder, et al, 2021: Initial evaluation and management of suspected acute coronary syndrome (myocardial infarction, unstable angina) in the emergency department)

As such, the indications in the Cardiac Ischemia Medical Directive are “suspected cardiac ischemia”, and the conditions do not mention pain/pressure of discomfort.

Furthermore, the companion document describes nitroglycerine as a symptom relief medication that has not demonstrated changes in a patient’s morbidity/mortality.

We recommend you tailor your cardiac ischemia management plan and nitro administration to the needs and presentation of your patient.

Please ensure information, clinical picture, pertinent +/- and rationale supporting your management plan are documented.

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