SA Node Dysfunction | Harrison Simplified

Описание: SA Node Dysfunction (Sick Sinus Syndrome) explained in a clear, structured, and simplified way — based on Harrison’s Principles of Internal Medicine (22nd Edition).

This video covers the full clinical understanding of disorders affecting the heart’s natural pacemaker, focusing on mechanisms, diagnosis, and management.

🔍 Topics covered:
0:00 – Introduction to SA Node Dysfunction
Understanding the heart’s natural pacemaker and why a slow heart rate does not automatically mean a pacemaker is needed.

1:40 – Anatomy & Function of the SA Node
Location, cellular structure, and heterogeneous nature of the SA node.

4:49 – Aging & Heart Rate
How aging affects intrinsic heart rate and physiologic compensation.

5:25 – Definition of SA Node Dysfunction (SND)
When the SA node becomes unreliable in generating or conducting impulses.

6:08 – Impulse Formation Disorders
• Sinus bradycardia
• Sinus arrest
• Chronotropic incompetence

9:10 – Impulse Conduction Disorders (SA Exit Block)
• Type I
• Type II
• Type III
Mechanism and ECG patterns.

13:17 – Tachy-Brady Syndrome
Alternating fast and slow rhythms, the medication paradox, and management challenges.

17:32 – Causes of SND: Intrinsic Factors
Aging, fibrosis, ischemia, structural heart disease, infiltrative diseases.

20:07 Causes of SND: Extrinsic Factors
Medications, hypothyroidism, Lyme disease, sleep apnea, increased vagal tone, carotid sinus hypersensitivity.

27:44 – Clinical Presentation
Dizziness, syncope, fatigue, exercise intolerance.

28:14 - Diagnostic Tools
• ECG
• Holter monitoring
• Wearables / smartwatches
• Invasive electrophysiology
Importance of symptom–rhythm correlation.

33:25 – Management Approach & Pacemaker Indications
Stepwise evaluation, reversible causes, and pacing decisions based on symptoms.

35:54 – Pacemaker Technology & Types
• NBG code explained
• Rate-responsive pacing
• Single vs dual chamber devices
• Complications
• Leadless pacemakers

🎯 Designed for medical students, residents, and exam preparation, with a focus on clinical reasoning and real-world application.
PDF SLIDES
https://drive.google.com/file/d/1780L...