EKG Chapter 11

Supraventricular Arrhythmias

NFL Veterans and Atrial Fibrillation

  • New study suggests NFL veterans face a higher risk of atrial fibrillation (AFib) that can lead to stroke.

  • Key findings:
      - Former NFL players were nearly six times more likely to have AFib compared to men of similar age who did not play professional football.
      - Despite having fewer conventional risk factors for cardiovascular disease (e.g., Type 2 diabetes, high blood pressure) and lower resting heart rates, the athletes showed higher risk.
      - This study is the first to connect AFib with strength-based elite sports.
      - Lead author Dr. Dermot Phelan emphasizes the importance of vigilant checks for AFib among this group since many were unaware of symptoms.

  • Definition and Mechanism of AFib:
      - AFib occurs when electrical impulses that initiate each heartbeat fire erratically, causing the atria (top chambers of the heart) to quiver.
      - Quivering causes blood to pool in the atria, leading to clot formation which can travel to the brain and cause stroke.
      - Pacemakers are used to treat electrical conduction problems in the heart.

  • Previous studies link long-term endurance sports with increased AFib.

  • Potential physiological change: Prolonged strength training may increase heart chamber size and wall thickness, affecting heart rhythms and electrical signals.

  • Study demographics:
      - Compared 460 former NFL players to 925 non-players, with both groups being middle-aged (approx. half were African American).
      - AFib prevalence: 5% in former players vs. 0.5% in control group.
      - Higher AFib risk observed in older, white, heavier men.

Heart Changes and Increased Cardiovascular Risk in Football Players

  • Date: February 28, 2018

  • Findings from research presented at the American College of Cardiology's 67th Annual Scientific Session:
      - Football players show structural changes in the heart, linked to increased risk of heart rhythm disorders later in life.
      - Former NFL players found to be more than five times as likely to have heart rhythm disorders, such as AFib, compared to the general public.
      - First study to find such associations in athletes primarily engaged in strength-based sports.

Sudden Cardiac Arrest

  • Definition: Sudden cardiac arrest occurs when the heart unexpectedly stops beating due to electrical malfunction.

  • Statistics:
      - Approximately 1 in 50,000 athletes per year (with 8 million athletes total).
      - Results in about 150 incidents yearly.
      - For NCAA athletes, the rate is 1 in 60,000, resulting in greater than 500,000 NCAA athletes; approximately 8 incidents per year.
      - Notably, NCAA basketball shows a higher incidence rate of 1 in 20,000, equating to roughly 25 athletes per year.

Athlete's Heart vs Normal Heart

  • Normal Heart: Regular size and function.

  • Athlete's Heart:
      - Characterized by:
        - Thickened heart muscle
        - Enlarged left ventricle

  • Source: Cleveland Clinic, ©2023

Hypertrophic Cardiomyopathy (HCM)

  • Definition: A genetic heart condition causing thickening of the heart muscle, affecting 1 in 200-500 people worldwide.

  • Symptoms: Can result in abnormal heart function, reduced blood flow out of the heart, or abnormal heart rhythm.

  • Exercise guidance for individuals with HCM:
      - Mild to moderate physical activities improve fitness, quality of life, and lower traditional cardiac risk factors (e.g., high blood pressure, high cholesterol).
      - High-intensity activity or competitive sports may be possible under evaluation and guidance by an HCM expert.

  • Important notes:
      - Requires individualized exercise programs.
      - A comprehensive Emergency Action Plan (EAP) is needed for managing potential cardiac emergencies.
      - Defibrillators (AEDs) must be accessible within 3-5 minutes; CPR and AED training recommended for all stakeholders.
      - Warning signs to monitor include worsening shortness of breath, dizziness or fainting, chest pain, and heart palpitations.

  • References and faculty mentioned for further reading:
      - Ommen SR, Mital S, et al. Circulation. 2020 Dec 22;142(25):e558-e631.
      - Abbreviations:
        - ICD: Implantable Cardioverter-Defibrillator
        - EAP: Emergency Action Plan
        - AED: Automated External Defibrillators
        - CPR: Cardiopulmonary Resuscitation

Supraventricular Arrhythmias

Introduction

  • Definition: An abnormal electrical activity originating above the ventricles, particularly in the atria or the Atrio-Ventricular (AV) node (excluding the Sino-Atrial (SA) node).

  • Characteristic heartbeat rates: Ranges > 100 bpm (up to 300 bpm).

Types of Supraventricular Arrhythmias

  • Premature Atrial Contractions (PACs):
      - Common, generally benign occurrences where any cardiac cell can initiate impulses, leading to early beats and atrial ectopic beats.
      - ECG Appearance:
        - P wave may differ in shape or size from the sinus P wave.
        - QRS complex follows the P wave and is typically followed by a compensatory pause.
        - Visible in all leads.
      - Patterns:
        - Couplets, Atrial bigeminy, Atrial trigeminy, Atrial quadrigeminy, Atrial tachycardia.
      - Causes:
        - Stress, caffeine consumption, fatigue, nicotine usage, and electrolyte imbalance.
      - Treatment:
        - Smoking cessation, limiting caffeine intake, potassium replacement, pharmacological treatment, or catheter ablation.

  

  • Premature Junctional Contractions (PJCs):
      - Originates from the AV node, typically when the SA node fails or is diseased.
      - ECG Appearance:
        - P wave may be absent, inverted, or retrograde; patterns vary.
      - Causes are similar to PACs and PVCs, plus SA node failure.
      - Treatment is generally benign, no specific treatment needed;
        - Junctional rhythm: HR = 40-59 bpm
        - Accelerated junctional rhythm: HR 60-100 bpm
        - Junctional tachycardia: HR > 100 bpm (may require pharmacologic treatment).

  

  • Atrial Flutter:
      - ECG Appearance: Displays a “saw tooth” pattern; R-R waves may be regular or irregular depending on AV block consistency.
      - Treatment:
        - Antiarrhythmic agents, Adenosine to slow heart rate, emergency synchronized cardioversion if necessary.

  

  • Atrial Fibrillation:
      - Most common arrhythmia, can occur in both healthy and diseased hearts.
      - Potential life-altering complications include embolic stroke and tachycardia-induced cardiomyopathy.
      - Mechanism: Atria fire chaotically at approximately 300-500 bpm, leading to ineffective atrial contraction; clot formation risk increased, resulting in symptoms like activity intolerance, shortness of breath, and heart palpitations.
      - ECG Appearance: Characterized by a wavy baseline, no discernible P waves, and an irregular R-R interval.
      - Types: Atrial fibrillation can be paroxysmal (intermittent) or permanent.
      - Risk Factors:
        - Advanced age, enlarged atria, increase in incidence with stress, fatigue, dehydration, and excessive intake of alcohol, caffeine, or recreational drugs.
      - Pharmacologic Treatment:
        - Anticoagulants (Heparin, Warfarin/Coumadin, Eliquis) for stroke prevention; INR testing to evaluate blood clotting time.
        - Antiarrhythmic drugs are also used.
        - Potential complications from anticoagulants include bruising, blood in urine/stool, excessive menstrual bleeding.
      - Additional resource: Healthline for natural blood thinners like ginger.

Additional Considerations

  • Sleep Apnea:
      - Discussion on causes, signs/symptoms, impacts on heart and brain, and increasing risk for several conditions.
      - Mention of CPAP machines and sleep apnea tests.

Questions?

  • Open floor for any further inquiries relating to the subject matter.