Cardiology ­ ECG Basics. ● Anatomy: 

 ● Function of the heart is mainly pumping the blood, Regulate the circulation. ● Valves of the heart:

A. Semilunar: 1. Aortic: between Left Ventricle and Aortic Arch. 2. Pulmonary: between Right Ventricle and Pulmonary artery.

B. A-V (Atrioventricular): 1. Mitral: between Right Atrium and Right Ventricle. 2. Tricuspid: between Left Atrium and Left Ventricle.

● Heart position is in the posterior to Mediastinum, on left side of chest. ● Heart size is Closed Fist, when opening the chest first part you see is Right

Ventricle, the Most Anterior.

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1 Created by: Hawra Al­Eirani 

● Heart Layers: (outer to inner) 1. Pericardium. 2. Myocardium. 3. Endocardium.

● Circulation of the Blood:

Deoxygenated blood flows from the body to Superior & Inferior Vena Cava to Right Atrium to Right Ventricle to Pulmonary artery to Lung to Pulmonary vein (Oxygenated blood) to Left Atrium to Left Ventricle to Aorta to The Whole Body.

● Cardiac Cycle Stages:

● Borders of the Heart: ❏ Right Border:

a. Superior & Inferior Vena Cava. b. Right Atrium.

❏ Left Border: a. Left Atrium & Ventricle. b. Pulmonary Artery. c. Aortic Artery.

❏ Inferior Surface: a. Right Ventricle. b. Apex (Left Ventricle).

● Blood Supply to the heart muscles is the Coronary Arteries: 1. Right Coronary Artery (RCA): Posterior Interventricular Artery (PIV) (80%). 2. Left Main Coronary Artery (LCA): Left Circumflex Artery (15%).

● Controlling of Blood Flow: Valves: 1. During Systole:

a. A-V Closed. b. Semi Lunar Opened.

2. During Diastole: a. A-V Opened. b. Semi Lunar Closed.

● S1 Sound occur in the Systole due to [Closure of A-V], S2 Sound occur in Diastole due to [ Closure of Semilunar].

● Myocardium cells work as Sensorium (work as one), any damage to the cardiac tissues, cardiac biomarkers will be released (Troponin, Myosin, CK-MB).

● Conduction System: [Sinoatrial (SA) to Atrioventricular (AV) to Bundle Branch/Purkinje fibers].

● SA node (pacemaker) sends impulses to the AV, The AV node waits a while before sending impulses (so the Ventricles can relax and get filled with blood to contract). Then, the AV node sends the Impulses Through the Bundle Branches then, to Purkinje fibers.

● Stroke Volume = 70-80 ml ejected with every beat. ● Abnormal Sounds (Murmurs):

❏ Stenosis Sound is heard when the Valve is Open. ❏ Regurge Sound is heard when the Valve is Closed.

1. In A-V Valves: A. Diastole: (Mitral, Tricuspid) are Open, Stenosis occur. B. Systole: (Mitral, Tricuspid) are Closed, Regurgitation occur.

2. In Semi Lunar Valves: A. Diastole: (Aortic, Pulmonary) are Closed, Regurgitation occur. B. Systole: (Aortic, Pulmonary) are Open, Stenosis occur.

● Electrocardiogram (ECG): ● Leads:

Lead 1 aVF for Axis

+ + Normal

- - Undetermined

- + Right Axis

+ - Left Axis

● Axis Deviation: (Lead1 + aVF = look at QRS upwards or downwards). 1. Left Axis Deviation:

2. Right Axis Deviation:

3. Odd Axis Deviation: Both lead 1 and lead aVF will be pointing downwards.

● Basic Normal ECG Paper:

● In paper: 1 Big Square (has 25 small squares) = 0,2sec. Therefor, In 1 min =300 Big Square.

● Rhythm: (Between R-R). 1. Regular Rhythm. 2. Irregular Rhythm.

❏ Irregular Regular. ❏ Irregular Regular.

● Heart Rate: HR= 300/no. of big squares, (look at Lead 2, P-R Interval normally takes 3-5 small squares).

1. Tachycardia > 100 beat/min.

2. Bradycardia < 60 beat/min.

● Waves: 1. P Wave: Atrial Depolarization (Any problem with atriums will show in

this wave on ECG). 2. QRS Complex: Ventricular Depolarization, Atrial Depolarization

(Ventricular Depolarization is stronger than Atrial Repolarization). 3. T Wave: Ventricular Repolarization .

● Segments: (Iso-Electric Line) 1. ST Segment: To Identify Ischemia. 2. PR Segment: For AV Activity. 3. TP Segment: For the Baseline.

● Interval: (consist of Wave + Segment) 1. PR interval: P wave + PR Segment. 2. QR interval: QRS Complex + ST segment.

● Conduction Abnormalities: 1. Shortness Abnormalities (Pre-excitation):

A. Wolff Parkinson White Syndrome (WPW): I. Wide QRS. II. Short P-R Interval.

III. Delta wave (Slurring).

B. Lown Ganong Levine Syndrome (LGL): AV node sends impulses directly. I. Short P-R Interval. II. Normal QRS.

2. Prolonged Abnormalities (Heart Block): I. 1st Degree: Delayed Conduction Through AV node. (All impulse arrive

but delayed). Prolonged P-R Interval.

II. 2nd Degree: Half the impulse arrive and half don't. A. Mobitz 1/ Wenckebach: Progressive prolongation of P-R Interval

until a P-wave is completely blocked. (worsen with each cycle).

B. Mobitz 2: Sudden blocked beat, not preceded by a change in duration on P-R Interval.

III. 3rd Degree: Complete Heart Block. (Blocked Atrial beats,No P-wave).

● Ectopic Foci: an abnormal pacemaker sites within the heart (outside of the SA node) that display automaticity, which can cause additional beats (observed as premature beats) or take over the normal pacemaker activity of the SA node. These ectopic pacemakers can lead to either tachycardia or bradycardia.

● QRS Complex Abnormalities: 1. Left Ventricular Hypertrophy: (look at V1 = S wave and V6 = R wave).

To say a patient is hyper trophic V1+V6 = 35 and above. ( we count ‘S’ big Squares Longitudinally, and ‘R’ big squares Longitudinally, each multiplied in 5 then added together).

2. Right Ventricular Hypertrophy: Tall R, (look at V1 and V6).

● Bundle Branch Block (BBB): (look at V1,V6) 1. Left Bundle Branch Block (LBBB):

2. Right Bundle Branch Block (RBBB): ( V1:‘R’ wide: has M Shape, V6:’S’ wide: has M shape).