Heart-rhythm conditions, explained.

Pregnancy changes the heart's workload, hormones, and blood volume — and that changes how rhythm problems behave. Most arrhythmias in pregnancy are benign, but a few need careful management. We work closely with your obstetrician throughout.

An irregular, often rapid heartbeat that starts in the upper chambers of the heart. AFib is the most common sustained arrhythmia and a leading cause of stroke.

A fast, organized rhythm in the upper chambers of the heart driven by a single large electrical loop. Atrial flutter is a close cousin of atrial fibrillation — the two often coexist and convert into each other — and carries the same stroke risk.

A breakdown in the electrical wiring between the upper and lower chambers of the heart. The severity ranges from a harmless delay to a complete disconnection that requires a pacemaker.

A delay or interruption in one of the main electrical wires that carries each heartbeat down to the lower chambers of the heart. Some bundle branch blocks are harmless; others point to underlying heart disease and change how we treat it.

A form of fast rhythm from the lower chambers of the heart that occurs in patients with otherwise completely normal hearts. Unlike scar-mediated VT, it does not carry the sudden-death risk most people associate with the term, and it is usually highly curable.

The awareness of your own heartbeat — usually as a flutter, skip, thud, or racing sensation. Common, usually harmless, but occasionally the first clue to an arrhythmia worth treating.

Extra beats from the upper chambers (PACs) or lower chambers (PVCs) are extremely common, usually benign, and often felt as a 'skipped beat' or a hard thump. A small minority of patients with a very high PVC burden need more attention.

A condition where the heart's natural pacemaker becomes unreliable — pacing too slowly, pausing, or failing to speed up appropriately with activity. Pacemakers are the definitive treatment when symptoms are present.

A family of fast heart rhythms that start above the ventricles and turn on and off abruptly. Most forms are not dangerous, and catheter ablation cures the vast majority of them.

A fast heart rhythm that originates from the lower chambers of the heart. Depending on its cause, VT ranges from a benign nuisance to the most common mechanism of sudden cardiac death.

Ventricular fibrillation is a chaotic rhythm of the lower chambers that stops the heart from pumping. Without immediate CPR and a defibrillator shock, it is fatal in minutes. Survivors need careful evaluation to find the cause and prevent it from happening again.

A congenital wiring variant of the heart in which an extra electrical bridge connects the upper and lower chambers. Most people with this wiring are fine, but a small fraction develop fast rhythms — and a smaller fraction face a real risk of sudden cardiac death.

A group of conditions where the autonomic nervous system — the part of the nervous system that runs heart rate, blood pressure, digestion, and temperature in the background — doesn't regulate properly. POTS is the form we see most often in our clinic.

A sudden, brief loss of consciousness caused by a temporary drop in blood flow to the brain. Most syncope is benign, but a small subset has a cardiac cause that we need to identify.

An inherited electrical condition with a characteristic ECG pattern and a small but real risk of sudden cardiac death, often during sleep or fever. Recognizing it early lets us avoid triggers and protect the highest-risk patients with an ICD.

A genetic condition in which the heart muscle becomes abnormally thickened. Most patients live full lives; a minority face sudden-death risk or symptoms from obstruction that need targeted treatment.

A small group of genetic conditions that affect the heart's electrical system. They tend to run in families, can cause dangerous rhythms even in structurally normal hearts, and benefit enormously from early recognition. We screen, monitor, and treat — and we coordinate with your relatives when appropriate.

An electrical condition — either inherited or triggered by medications — that prolongs the heart's recovery time after each beat and predisposes to a specific dangerous rhythm called torsades de pointes.

Two diseases that infiltrate the heart muscle and disrupt its electrical wiring. Both can cause heart failure, abnormal rhythms, and conduction problems — but they are caused, diagnosed, and treated very differently from each other once recognized.

When the heart's pumping strength is reduced, two things go wrong: forward flow weakens, and the risk of dangerous rhythms rises. Cardiac resynchronization and defibrillators address different parts of that problem.

An infection of an implanted pacemaker, defibrillator, or CRT system — either at the pocket where the device sits or on the leads inside the heart. Once the hardware is infected, antibiotics alone cannot cure it, and the entire system has to be removed.