Blackouts: Clinical Meaning

Cardiac Arrhythmia

Cardiac arrhythmia refers to irregular heart rhythms — the heart beats too fast, too slow, or with an irregular pattern. Some arrhythmias are harmless, while others (like atrial fibrillation) significantly increase the risk of stroke and heart failure.

Pulmonary Embolism

Pulmonary embolism is a life-threatening blockage of the pulmonary arteries, usually by clots from deep vein thrombosis. Sudden shortness of breath, chest pain, and rapid heart rate are classic presentations requiring emergency treatment.

Aortic Stenosis

Aortic stenosis is narrowing of the aortic valve opening, restricting blood flow from the heart. It causes exertional chest pain, syncope, and heart failure; valve replacement is required for severe symptomatic disease.

Hypotension (Low Blood Pressure)

Hypotension is defined as blood pressure below 90/60 mmHg, causing dizziness, fainting, and fatigue. Causes include dehydration, prolonged standing (orthostatic hypotension), heart problems, and certain medications.

Atrial Fibrillation

Atrial fibrillation (AFib) is the most common cardiac arrhythmia, characterized by rapid and irregular atrial beating. It significantly increases stroke and heart failure risk.

Cardiac Tamponade

Cardiac tamponade is a life-threatening emergency where fluid accumulates in the pericardial sac, compressing the heart and impairing its ability to pump blood effectively.

Aortic Dissection

Aortic dissection is a life-threatening emergency in which the inner layer of the aorta tears, allowing blood to surge between the vessel walls. It typically presents with sudden, severe tearing or ripping chest or back pain radiating to the back, and requires immediate surgical evaluation.

Subarachnoid Hemorrhage

Subarachnoid hemorrhage is bleeding into the subarachnoid space surrounding the brain, most often caused by a ruptured cerebral aneurysm. It classically presents with a sudden, severe thunderclap headache described as the worst headache of life, accompanied by nausea, vomiting, and neck stiffness.