What should I do now?
Call 911
Call 911 for collapse, fainting with racing, chest pressure, severe trouble breathing, or repeated ICD shocks. If someone is unresponsive and not breathing normally, follow the dispatcher's CPR/AED instructions.
Contact your care team
After one ICD shock with complete recovery, contact your device team promptly and follow your personal plan. Report recurrent racing or new symptoms.
Keep your care plan
Keep your treatment and follow-up plan. Bring questions, readings, and your medication list.
SECTION 2
What symptoms can VT and VF cause?
Symptoms of ventricular tachycardia
During VT, the heart may beat too quickly to pump enough blood to the brain and body. Patients may experience:
- A racing, pounding, or fluttering heartbeat.
- Dizziness or lightheadedness.
- Feeling faint or passing out.
- Shortness of breath.
- Chest pain or pressure.
Some brief episodes cause no noticeable symptoms and are discovered on a heart monitor. Feeling well during an episode does not necessarily mean the rhythm is safe.
What happens during ventricular fibrillation?
VF causes cardiac arrest. The ventricles cannot pump blood effectively, and the person quickly loses consciousness.
Signs include:
- Sudden collapse.
- No response when spoken to or tapped.
- No normal breathing, or only gasping.
There may be little or no warning before the collapse.
When should you call 911?
Call 911 immediately for a racing heartbeat accompanied by chest pain, fainting, severe dizziness, or severe shortness of breath. Do not drive yourself.
If someone collapses, is unresponsive, and is not breathing normally:
- Call 911 and put the phone on speaker.
- Start CPR, following the dispatcher’s instructions.
- Use an AED as soon as one is available and follow its prompts.
Do not wait for a watch or home monitor to confirm the rhythm before getting help.
Updated October 2026. Educational information; your own care plan may differ. Heart illustrations and EKG examples are simplified for teaching.