Cardiac Arrhythmias Overview

Definition

• Disorder of formation or conduction of electrical impulses within the heart.

• Irregular heart rate and rhythm essential for normal body functioning.

Risk Factors for Arrhythmias

• Heart Failure: Impairs heart function.

• Chronic Respiratory Diseases (CRPD): Affects oxygenation and heart efficiency.

• Smoking: Impacts cardiovascular health.

• Age: Increased risk of arrhythmias as age progresses.

• History of Myocardial Infarction (MI): Previous heart attacks increase risk.

• Sleep Apnea: Disrupts breathing and can lead to arrhythmias.

• Diabetes: Contributes to vascular damage and heart issues.

Electrical Conduction System of the Heart

Sinoatrial Node (SA Node)

• Stimulates heart rhythm; initiates electrical impulses.

Conduction System Sequence (Mnemonic)

• Use mnemonic based on "branches of peaches" to remember the conduction sequence.

Key Concepts: Depolarization and Repolarization

• Depolarization: Cells become less negative, leading to contraction (associated with systolic blood pressure).

• Repolarization: Cells return to a negative charge, leading to relaxation (associated with diastolic blood pressure).

Influences on Heart Rate

Autonomic Nervous System

• Sympathetic Nervous System: Increases heart rate and force of contraction (Chronotropic, Dromotropic, Inotropic).

• Parasympathetic Nervous System: Decreases heart rate and dilates blood vessels.

Electrocardiograms (EKG)

Purpose and Types of EKGs

• EKG: Records electrical impulses of the heart.

• Types:

  • Bedside EKG: Immediate use, 12-lead.

  • Hardwired Monitoring: Continuous monitoring.

  • Holter Monitor: Worn for 24 hours; tracks heart activity during normal activities.

  • Loop Recorder: Implanted device that records abnormal heart rhythms.

EKG Lead Placement

• Correct placement ensures accurate readings (e.g., "Smoke over Fire, Snow over Grass" mnemonic).

Cardiac Waves and Complexes

Key Waves to Remember

• P Wave: Atrial depolarization.

• QRS Complex: Ventricular depolarization (contraction).

• T Wave: Ventricular repolarization (relaxation).

Common Arrhythmias

Bradycardia

• Heart rate < 60 bpm.

• Causes: Reduced metabolic needs, aging.

• Symptoms: Altered mental status, low blood pressure, chest discomfort, exercise intolerance, fatigue, dizziness, headaches, nausea, palpitations, SOB

• Dx: ECG, loop recorder, holter monitor, electrophysiologic testing

• Treatments: Atropine, warfarin, potential pacemaker placement (artificial or dual chamber(1 lead paces atria, 1 lead paces ventricles)

Tachycardia

• Heart rate > 100 bpm.

• Causes: Fever, anxiety, exercise, blood loss, shock, caffeine, pain, HF.

• Symptoms: Fatigue, orthostatic hypotension, palpitations, exercise intolerance, blurred vision, dizziness.

• Treatments: Vagal maneuvers (gagging, beating down, forceful cough), adenosine administration, potential cardioversion.

POTS Syndrome

• Ineffective blood circulation adjustments.

• Symptoms: dizziness, sweating, fatigue, SOB, chest pain, palpitations.

• Treatment: Increased fluids and salt intake, Gatorade, pedialyte, avoid caffeine, avoid prolonged standing.

Atrial Fibrillation (AFib)

Characteristics

• Abnormal pattern of contractions; uncoordinated twitching. HR 100-175

• Symptoms: Palpitations, fatigue, shortness of breath, difficulty exercising, anxiety, chest pain, dizziness.

• Risk factors: Excessive alcohol, thyroid disorders, family history, advanced age, male gender, inflammation, sleep apnea, cardiovascular disease, echocardiographic abnormalities.

• Treatment: Wait to see if it resolves, anticoagulants, or invasive procedures if persistent.

Ventricular Tachycardia (V-Tach)

Types and Treatments

• Monomorphic V-Tach: Single, consistent rhythm.

• Polymorphic V-Tach: Variable rhythms.

• Treat with medication (amiodarone) and cardioversion for monomorphic, defibrillation for polymorphic.

Pacemaker Therapy

Overview

• Electronic device to regulate heart rhythm.

• Types: Permanent and temporary pacemakers.

• Patient monitoring: Infection, pneumothorax risk, daily pulse logging.

Procedures Related to Arrhythmias

Cardioversion

• Used for arrhythmias to restore normal rhythm.

• Involves synchronization with patient sedation and monitoring.

Ablation Therapy

• Minimally invasive procedure to correct arrhythmias.

• Can involve catheter insertion from groin or wrist.

Left Atrial Appendage Closure

• Reduces stroke risk in AFib patients with anticoagulant contraindication.

• Patients undergo follow-up to ensure effectiveness.

Conclusion

• Understanding cardiac arrhythmias is vital in clinical practice for patient safety and effective treatment.