Can Heart Attack Occur Even With Normal Blood Pressure?
Yes, myocardial infarction can absolutely occur in patients with normal blood pressure. 1
Understanding the Relationship Between Blood Pressure and MI
While hypertension is a major risk factor for developing coronary artery disease over time, the presence or absence of normal blood pressure at the time of presentation does not determine whether someone is having or can have a heart attack. 2 This is a critical distinction that clinicians must understand:
Type 1 MI (Spontaneous) Can Occur Regardless of Blood Pressure
- Atherosclerotic plaque rupture, ulceration, fissuring, erosion, or dissection can occur in patients with normal blood pressure, leading to intraluminal thrombus formation and myocardial infarction. 1
- Patients may have underlying severe coronary artery disease, but 5-20% of MI patients have non-obstructive or no significant CAD on angiography, particularly in women—and this occurs independent of blood pressure status. 1
Type 2 MI Explicitly Includes Normal and Abnormal Blood Pressure States
The Third Universal Definition of Myocardial Infarction specifically lists both hypotension AND hypertension as potential triggers for Type 2 MI (supply-demand mismatch). 1 This means:
- Myocardial infarction can result from an imbalance between myocardial oxygen supply and demand caused by conditions including coronary endothelial dysfunction, coronary artery spasm, coronary embolism, tachyarrhythmias, bradyarrhythmias, anemia, respiratory failure, hypotension, or hypertension with or without left ventricular hypertrophy. 1
- The key pathophysiology is the supply-demand mismatch, not the absolute blood pressure value. 1
Critical Clinical Pitfall to Avoid
Never use the presence or absence of hypertension to determine whether to admit or treat for acute coronary syndrome. 2 The American Heart Association explicitly warns that:
- Traditional risk factors including hypertension have limited acute predictive value in patients presenting with possible acute coronary syndrome. 2
- Symptoms, ECG findings, and cardiac biomarkers are far more important than blood pressure for determining whether to admit or treat for ACS. 2
Why This Matters for Risk Assessment
While hypertension increases long-term MI risk through multiple mechanisms (accelerated atherosclerosis, left ventricular hypertrophy, increased myocardial oxygen demand), 2, 3:
- Approximately 49% of patients experience MI as the first manifestation of ischemic heart disease, meaning they had no prior symptoms regardless of their blood pressure history. 4
- Blood pressure is actually a poor predictor of individual cardiovascular events—persons in the top 10% of systolic blood pressure distribution experience only 21% of all ischemic heart disease events and 28% of all strokes. 5
Bottom Line for Clinical Practice
Evaluate every patient with chest pain or ischemic symptoms based on their presenting symptoms, ECG changes, and cardiac biomarkers—not their blood pressure reading. 2 Normal blood pressure does not exclude MI, and the diagnosis requires:
- Detection of a rise and/or fall in cardiac biomarker values (preferably cardiac troponin) with at least one value above the 99th percentile upper reference limit. 1
- Plus at least one of: symptoms of myocardial ischemia, new ischemic ECG changes, development of pathological Q waves, or imaging evidence of new loss of viable myocardium. 1