Cardiac arrhythmia — an irregular heartbeat — occurs when the electrical impulses that coordinate your heart’s rhythm misfire. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or erratically.

Some arrhythmias are harmless; others can be life-threatening, raising the risk of stroke, heart failure, or sudden cardiac arrest. The most common type is atrial fibrillation (A-fib), which affects millions of Americans — many without knowing it. Risk increases with age, heart disease, high blood pressure, diabetes, smoking, and heavy alcohol use.

Classic Symptoms

• Racing, fluttering heartbeat (palpitations)
• Dizziness or lightheadedness
• Shortness of breath
• Fatigue
• Chest discomfort
• Fainting (syncope)

Surprising Red Flags

Experts say these less obvious signs can also point to arrhythmia:

• Panic attacks. Sudden rhythm changes can trigger adrenaline surges that mimic anxiety.
• Confusion. Low oxygen to the brain may cause memory issues or mental fog, often mistaken for dementia in seniors.
• Nausea. Irregular beats can drop blood pressure, reducing blood flow to the stomach.
• Frequent nighttime urination. A 2022 study linked waking two or more times at night to structural heart changes seen in A-fib.
• Persistent cough. Certain arrhythmias affect the vagus nerve or lung blood flow, sparking a cough.