Can Dehydration Cause Angina?
Yes, dehydration can precipitate or exacerbate angina by creating a supply-demand mismatch in the myocardium, particularly when accompanied by volume contraction and hyperthermia. 1
Mechanism of Dehydration-Induced Angina
Dehydration triggers angina through decreased myocardial oxygen supply rather than increased demand:
Volume contraction reduces coronary perfusion pressure, particularly affecting subendocardial blood flow in patients with underlying coronary stenoses 1
Hyperthermia combined with volume depletion is specifically recognized by ACC/AHA guidelines as a precipitating condition that can cause angina even without significant anatomic coronary obstruction 1
Increased blood viscosity from hemoconcentration decreases coronary artery blood flow, similar to mechanisms seen in polycythemia and hypergammaglobulinemia 1
Acute kidney injury from severe dehydration can further compound cardiovascular stress, as demonstrated in case reports of young adults developing ST-elevation myocardial infarction following prolonged sun exposure and dehydration 2
Clinical Context and Risk Stratification
The likelihood of dehydration causing angina depends on underlying coronary anatomy:
Patients with pre-existing coronary stenoses are most vulnerable, as dehydration unmasks the supply-demand mismatch 1
Severe dehydration can precipitate angina even in patients without significant coronary obstruction when volume depletion is profound enough to compromise coronary perfusion 1
Young patients without atherosclerosis can still experience acute coronary events from severe dehydration through mechanisms including coronary vasospasm and thrombosis 2
Important Clinical Caveats
Nitroglycerin use requires extreme caution in dehydrated patients:
Volume-depleted patients are at high risk for severe hypotension with nitroglycerin administration 3
Hypotension induced by nitroglycerin may be accompanied by paradoxical bradycardia and increased angina pectoris 3
Patients should be adequately hydrated before nitroglycerin administration when dehydration is suspected 3
Hydration status assessment is critical:
Look for signs of volume depletion including orthostatic vital sign changes, decreased skin turgor, dry mucous membranes, and elevated blood urea nitrogen-to-creatinine ratio 1, 2
Acute kidney injury markers suggest severe dehydration requiring aggressive fluid resuscitation 1, 2
Management Approach
Immediate rehydration is the primary intervention:
Intravenous fluid resuscitation with isotonic saline (250-500 mL boluses) should be initiated promptly 1
Monitor for improvement in anginal symptoms with volume repletion before escalating antianginal therapy 1
Exercise caution with fluid administration in patients with known heart failure 1
Prevention strategies for at-risk patients: