Cardiology Lecture Notes

1. Understanding Cardiac Rhythms

How to Approach Dysrhythmia Interpretation

• Identify waves: P, QRS, T
• Measure PRI: 0.12-0.20 seconds
• Determine QRS complex duration: <0.11 seconds
• Determine rhythm regularity and heart rate

Rhythms Originating in the SA Node

• Normal Sinus Rhythm: 60-100 BPM, regular rhythm, upright P-wave
• Sinus Bradycardia: <60 BPM, regular rhythm, treatment rarely needed
• Sinus Tachycardia: >100 BPM, regular rhythm, treatment rarely needed
• Sinus Dysrhythmia: Regularity varies with respiratory patterns, benign
• Sinus Arrest: Missed beats, causes include ischemia, vagal tone
• Sick Sinus Syndrome (SSS): Poor functioning SA node, varied symptoms

Rhythms Originating in the Atria

• Premature Atrial Complex (PAC): Irregular rhythm, early P-wave
• Supraventricular Tachycardia (SVT): >150 BPM, regular rhythm, treatment involves vagal maneuvers, adenosine
• Preexcitation Disorders: WPW & LGL syndromes, avoid certain medications
• Atrial Fibrillation (AFib): Irregular rhythm, no P-wave, risk of stroke
• Atrial Flutter (AFlutter): Sawtooth pattern, regular rhythm, risk of clot
• Multifocal Atrial Tachycardia (MAT): Irregular rhythm, different P-wave shapes

Rhythms Originating at the AV Junction

• Premature Junctional Complex (PJC): Early complex, irregular rhythm
• Junctional Escape Rhythm: 40-60 BPM, absent/inverted P-wave
• Junctional Tachycardia: >100 BPM, often caused by ACS

Rhythms Originating in the Ventricles

• Premature Ventricular Complex (PVC): Early complex, wide QRS
• Idioventricular Rhythm (IVR): 20-40 BPM, wide QRS
• Ventricular Tachycardia (VTach): >100 BPM, wide QRS, risk of VFib
• Ventricular Fibrillation (VFib): Chaotic, no organized QRS

Other

• Pulseless Electrical Activity (PEA): Organized rhythm without pulse
• Asystole: Cardiac standstill, non-shockable

2. 12-Lead ECGs

Indications

• Chest discomfort, electrical injury, syncope
• Obtain every 5-10 minutes in high-risk patients

Interpretation

• Identify waves, measure intervals, determine axis
• Look for conduction disturbances, zones of ischemia

Bundle Branch Blocks

• Left BBB: "W" in V1, "M" in V6 (WiLLiam)
• Right BBB: "M" in V1, "W" in V6 (MoRRow)

3. Congestive Heart Failure

Causes

• Coronary artery disease, hypertension, diabetes
• Thyroid disorders, drug use, dysrhythmias

Types

• Left Ventricular Failure: Blood backs up into lungs, dyspnea, hypertension
• Right Ventricular Failure: Blood backs up into venous system, edema, JVD

Treatment

• Left: Nitroglycerine, CPAP
• Right: Fluid bolus, manage ABCs

Cardiac Tamponade

• Compression of heart, decreased stroke volume, obstructive shock
• Causes include trauma, aortic dissection, cardiac rupture
• Signs: Beck’s Triad, pulsus paradoxus

Drugs and Treatment Protocols

Common Drugs

• Midazolam: Benzodiazepine for sedation, seizures
• Fentanyl: Opioid analgesic, pain management
• Ketamine: Dissociative analgesic, procedural sedation
• TXA: Hemostatic agent, for hemorrhage control
• Adenosine: Antidysrhythmic for SVT
• Albuterol: Bronchodilator for asthma
• Aspirin: NSAID, platelet inhibitor for ACS

ACLS Algorithms

• Bradycardia: Atropine, pacing, dopamine
• Tachycardia: Vagal maneuvers, adenosine, cardioversion
• Cardiac Arrest: Follow ACLS protocols for VFib, PEA, Asystole

These notes provide a high-level overview of the cardiology lecture content, focusing on rhythms, treatments, and key protocols in cardiology practice.