A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow to a portion of the heart muscle is abruptly reduced or blocked, leading to tissue injury. Although rare in the dental setting, MI is one of the most serious medical emergencies that can arise during treatment, especially when the patient is under sedation. Sedation can mask early symptoms, delay recognition, and complicate timely intervention.
This review provides an overview of MI physiology, risk factors relevant to dental care, how sedation affects recognition and management, and the critical steps dental teams must take to prevent and respond to cardiac emergencies.
Physiology of Myocardial Infarction
Myocardial infarction results from sustained ischemia due to obstruction of a coronary artery. The most common cause is rupture of an atherosclerotic plaque, forming a clot that restricts blood flow. As oxygen delivery decreases, heart muscle cells become damaged and begin to die, compromising cardiac function.
Symptoms often include chest pain or pressure, shortness of breath, nausea, sweating, or a sense of impending doom. However, not all patients experience typical symptoms—particularly those who are elderly, diabetic, or sedated, where presentations can be subtle.
Why MI May Occur During Dental Treatment
Dental procedures, including those performed under sedation, can introduce several physical and psychological stresses that increase cardiovascular workload:
Anxiety and fear, elevating heart rate and blood pressure
Pain or inadequate local anesthesia, which increases myocardial oxygen demand
Epinephrine in anesthetic solutions, which can potentiate tachycardia and hypertension
Preexisting cardiovascular disease, making patients more vulnerable to ischemic events
Prolonged or invasive procedures, increasing physiological stress
Although sedation aims to decrease stress, it also alters the patient’s ability to communicate warning symptoms and may mask hemodynamic changes until they become severe.
How Sedation Influences MI Recognition
Sedation impacts both the presentation of MI and the clinician’s ability to detect it:
Blunting of typical symptoms
Sedated patients may not fully recognize or verbalize chest pressure, radiating pain, or shortness of breath.
Altered level of responsiveness
Lethargy or decreased alertness, common effects of sedatives, may obscure early signs of cardiac distress.
Hemodynamic variability
Sedative drugs and procedural stress can cause fluctuations in heart rate and blood pressure, making it harder to distinguish early ischemia from expected drug effects.
Because MI under sedation may present quietly, continuous monitoring and vigilance are essential to early recognition.
Warning Signs of MI During Sedation
Even when communication is limited, several clinical cues can signal a developing myocardial infarction:
Pale, cool, or clammy skin
Sudden restlessness or agitation
Drop in oxygen saturation not explained by respiration
Unexplained bradycardia or tachycardia
Rising or falling blood pressure
Labored breathing
Complaints of chest pressure, even vaguely described
Nausea, vomiting, or sudden sweating
Any combination of these signs warrants immediate evaluation and potential emergency activation.
Prevention Strategies in the Dental Setting
Preventing MI begins with strong preoperative risk assessment and thoughtful procedural planning.
Comprehensive medical review
Identify patients with coronary artery disease, prior MI, stents, unstable angina, or heart failure. When needed, consult with the patient’s cardiologist.
Stress and anxiety reduction
Clear communication, supportive sedation titration, minimizing wait times, and providing reassurance all help maintain cardiovascular stability.
Adequate pain control
Use local anesthesia effectively, and re-administer as needed. Avoid prolonged discomfort, which increases cardiac workload.
Cautious use of epinephrine
Limit vasoconstrictor doses in high-risk cardiac patients, avoiding large or rapid injections.
Continuous vital sign monitoring
Pulse oximetry, blood pressure measurement, and ECG or capnography (when available) enhance early detection of physiologic decline.
Management of Suspected MI During Dental Treatment
If myocardial infarction is suspected, immediate and structured action is essential.
1. Stop the procedure
Terminate treatment, withdraw instruments, and call for assistance within the office.
2. Position the patient comfortably
Generally upright or semi-reclined to reduce cardiac stress and ease breathing.
3. Administer oxygen
Provide high-flow oxygen to improve oxygen delivery to cardiac tissues.
4. Activate emergency medical services (EMS)
Do this early—MI is a time-dependent emergency requiring rapid hospital intervention.
5. Provide aspirin if appropriate
If the patient is conscious and able to chew, a standard dose of aspirin may be given—unless contraindicated—because it inhibits clot progression. (Follow local protocols and review patient allergies/history.)
6. Monitor closely
Track blood pressure, heart rate, oxygen saturation, and responsiveness while preparing for potential deterioration.
7. Be prepared for cardiac arrest
MI can quickly lead to life-threatening arrhythmias. Dental teams must be ready to initiate CPR and use an automated external defibrillator (AED) immediately if the patient loses consciousness, stops breathing, or loses a pulse.
After the Event
Following an MI or suspected MI:
Document the event thoroughly
Inform the patient’s medical providers
Review internal emergency response performance
Evaluate whether future treatment requires a hospital-based setting
Post-event medical evaluation is essential even if symptoms resolve spontaneously.
Conclusion
Myocardial infarction during dental treatment under sedation is rare but poses significant risk. Because sedation can obscure symptoms and delay recognition, dental providers must rely on vigilant monitoring, clear protocols, and rapid action. With strong prevention strategies, thorough medical assessment, and immediate emergency response capabilities, dental teams can provide safe, effective care and reduce the likelihood of severe cardiac complications.
Myocardial Infarction During Dental Treatment Under Sedation: A Safety-Focused Review – Quick Quiz
Test your understanding of myocardial infarction risks, early warning signs, and emergency management during dental treatment under sedation.