Cardiovascular Outcomes - ECG Flashcards
Blood Pressure Measures (2)
Invasive: Gold standard, risky (infection). Tube inserted into artery and connected to a pressure transducer.
Non-invasive: Auscultory technique, both systolic and diastolic BP. Hypertension diagnosis should be confirmed by 24h BP measurement.
Non-invasive BP Measurement - Clinical Guidelines (Positioning)
Back supported, palm up, feet flat on the floor, no talking, mid arm at heart level, cuff 2 fingers above elbow line, measure both sides: if there is more than 20mmHg difference, could be a problem.
Pulse Rate Assessment
Strength, regularity and character.
Measure radial artery or carotid artery.
Measure for 30sec and double it.
Not the same as HR but can estimate it.
Heart Rate Variability
Normal!
HR ↓ with expiration, HR↑ with inspiration.
Low HRV: heart failure.
↑ during sleep: parasympathetic predominance.
Balance between autonomic branches.
Echocardiogram - Cardiovascular Measurement
Ultrasound (heart structures and vessels).
To assess hypertrophy, mobility and competence of valves, chamber dimensions, blood flow direction.
Ejection fraction: SV/end systolic volume.
Electrocardiogram (ECG/EKG)
Electrodes attached to the skin to detect electrical signals produced by the heart each time it beats.
ECG - Limb Leads (6)
Read electrical forces in the frontal plane.
Unipolar limb leads:
aVR: Augmented vector right. + on right shoulder.
aVL: Augmented vector left. + on left shoulder.
aVF: Augmented vector foot. + on foot.
Bipolar limb lead:
I: Axis from shoulder to shoulder, + on left shoulder, lateral wall (0°).
II: Right arm to left leg (+). 60° angle, inferior wall.
III: Left shoulder to leg (+). 120° angle, inferior wall.
ECG - Chest (Precordial) Leads (6)
V1-V6.
Read electrical forces in the transverse plane.
P, QRS and T Waves
P: Atrial depolarization. 0,06-0,12 sec.
QRS complex: Ventricular depolarization. 0,06-0,12 sec.
T: Ventricular repolarization. 0,10-0,25.
ECG - Calculations (values)
Small square: 0,04 sec
Big square: 5 small squares: 0,2 sec
Calculate beats per minute:
21,5x0,04sec=0,86 sec/beat
0,86/1=1,16 beats/sec
1,16x60=70 beats/minute
PR-Interval
Atrial impulse from SA-AV, from beginning of P-wave to beginning of Q. 0,12-0,22 sec.
QT-Interval
Time for full contraction and full relaxation. Beginning of Q to end of T. 0,36-0,44.
ST Segment - Elevated, Depressed and Inverted T
End of ventricular depolarization and beginning of ventricular repolarization (end of S beginning of T).
Elevated: STEMI, complete occlusion, myocardial necrosis.
Depressed: N-STEMI, myocardial ischemia due to arterial sclerosis.
Inverted T: Unstable angina, minimal occlusion, no necrosis.
Lead Views - Inferior, Lateral, Anterior, Septal
Inferior: II, III, aVF
Lateral: R: aVR, L: I, aVL, V5, V6
Anterior: V3, V4
Septal: V1, V2
ECG - Arrythmias
Sinus Tachycardia: >100bpm
Sinus Bradycardia: <60bpm
Respiratory sinus arrythmia: ↑HR in inhalation.
Atrioventricular Block
Partial or total block of impulse conduction through AV node.
Delayed impulse: prolonged PR-interval.
2 P-waves: needs 2 tries to get through.
Atrial Fibrillation
Loss of coordinated atrial contraction, turbulent blood flow.
↓ preload - ↓SV - ↓BP.
Irregular rhythm, can’t identify P and T waves.
Atrial Flutter
Rapid circuit that occurs in right atria close to tricuspid valve. Sawtooth: Can’t identify P and T waves but there is pattern and R is more regular.
Ventricular Fibrilation
Disorganized and ineffective contraction, impaired pump function. No cardiac output and no recordable BP. Can’t identify any of the waves.
Ventricular Extra Systole
Extra beat in ventricle.
Single, couplets, bigeminy, trigeminy.
Single: 1 extra.
Couplets: 2 extra.
Bigeminy: 1 normal, 1 extra.
Trigeminy: 2 normal, 1 extra.
3 or more classified as ventricular tachycardia.
Ventricular Tachycardia
Irregular electrical signals in ventricles. Heart cannot relax and fill properly. Very high peaks.
