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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.