THE HEART’S ELECTRICAL SYSTEM Marco Perez, MD Center for Inherited Cardiovascular Disease Inherited Cardiac Arrhythmia Clinic June 20, 2013

Electrical Pump

Main Electrical Problems Too Slow (Bradycardia, Heart Block) Fast, From the Top (Atrial Fibrillation, Atrial Tachycardia) Fast, From the Bottom (Ventricular Tachycardia)

Scarring & Stretching

Diagnosing Electrical Problems Symptoms Palpitations Skipped Beats Heart racing Heart Pounding Heart Fluttering Extra Heart Beats Sudden Passing Out Fatigue Lightheadedness Sometimes None Tests Electrocardiogram (ECG) Monitor

Monitors

Zio – 14 daysLINQ – 3 years

Pacemakers When do you need a Pacemaker? Heart Slows Down Too Much Heart Block on Monitor What does a Pacemaker Do? Small electrical impulse to heart Helps the heart keep beating

ICD (Implantable Cardiac Defibrillator) Function Detect Dangerous Heart Beats Deliver Electric Shock “Safety Net” Pacemaker functionality Implant procedure & risks – very similar Which patients need a Defibrillator? High Risk Passing Out Family history of sudden death Very thickened heart (3cm) Prior VT/VF BP and Exercise Scar on MRI Decision is Personal / Individualized

Pacemaker or ICD Placement Stanford Cath Lab

Device Procedure Duration: 1-2 hours Anesthesia Care Conscious Sedation General Anesthesia Recovery: Overnight in Hospital Sore for about a week Movement Limitations 4 weeks Then back to normal activities Device/Battery Checks: Every 3-6 months Major complication rates: < 1%

Atrial Arrhythmias 25% of HCM

Symptoms Variable Palpitations / “Heart Racing” Fatigue, Shortness of Breath Diagnosis: Irregular, often rapid pulse ECG

Treatments If no symptoms Control fast hear rates with medications If bothersome symptoms Stronger medications (antiarrhythmic) If no response to medications: ablation

Catheter Ablation Success rates General population (for intermittent AF): 60-80% In HCM/DCM: not as well studied Risks of Major Complication: 2-4%

Treatments Stroke Prevention Aspirin Coumadin or newer anti-coagulating medicine

Summary Heart is an electrical pump Very fast heart beats from top or bottom Implantable Cardiac Defibrillators For those at higher risk Atrial Fibrillation Start with medications May need ablation procedure Stroke prevention very important

Arrhythmia & Cardiac Genomics Teams familyheart.stanford.edu Allysonne Smith, RN

Familial Cardiomyopathy Clinic Familial Cardiomyopathy Clinic Inherited Arrhythmia Clinic Marfan syndrome & aortopathies Familial hyperlipidemia

Dangerous Arrhythmias Ventricular Tachycardia or Ventricular Fibrillation Rapid heart beats from the bottom Too fast  Collapse Too long  Fatal Frequency in MD: Not well studied Risk factor: Conduction System Disease (over 3x) Treatment: Electric Shock

Conduction System Disease Severity Depends on Location Usually Progressive - Starts with subtle findings - Develop Complete Block Cause: Not Known * Fibrosis * Cell-cell connections * Molecular Level

Symptoms Warning Signs Passing Out (Syncope) Chest Pain or Shortness of Breath Dizziness Sudden Fatigue “Skipped Heart Beats” Late: Heart Stops Beating

Other arrhythmias Frequent Premature Ventricular Contractions (PVCs) Common in MD (up to 14% of patients) Treat only if very frequent (20%) or Symptomatic Medications or Ablation