CARDIOVASCULAR OUTCOMES Flashcards
BLOOD PRESSURE: def, formula
= force of blood against blood vessel
BP = CO (Q) x TPR
CARDIAC OUTPUT: unit, formula, characteristics of each components
L/min
= heart rate x stroke volume
Heart rate
- divided in intrinsic (sino-atrial node) & extrinsic (Autonomic nervous system with sympathetic that increases HR & parasympathetic which decreases HR)
Stroke volume
= amount of blood pumping during each cardiac cycle
1) Preload = amount of blood coming to ventricle = venous return → Affects by valves function, muscles pump and posture
2) Afterload = how much resistance ventricle must to overcome squeeze blood → Affects by hypotension, vasoconstriction, stenosis of valves
3) Contractility
→ Affects by exercises & autonomic nervous system (sympathetic increases contractility & parasympathetic decreases contractility)
Total periphery resistance: def & characteristics
= friction of blood against blood vessel, as vessel relaxes → resistance decreases
Radius impact → vasoconstriction
→ Affects by hormones (epinephrine), temperature (cold = vasoconstriction), exercise & autonomic nervous system (sympathetic innervates vessel → vasoconstriction // parasympathetic does not innervates vessel)
BP: Invasive method: characteristics, ≠ types, utilization, common sites & risk
C: direct
≠: intravascular (tip catheter) & extravascular (arterial line with external transducer)
U: Tube inserted into artery & connected through saline fluid filled line to electrical pressure transducer
→ Catheter line must be free of air. Cannula & tubing stiff & short
CS: brachial, radial & femoral arteries
R: risk of infection
BP: non invasive method: characteristics, intermittent values, continuous waveform & goals
C = indirect
IV:
- Auscultatory (Korotkoff method)
- Oscillometric
- Ultrasonic method
CW:
- Tonometric
- Volume clamp (Penaz method)
G: Auscultatory technique, allowing measurement of both systolic & diastolic blood pressure
BP: office: description, traditional manual measurement & automated measurement
D: = most commonly basis for hypertension diagnosis & follow-up
- 2-3 office visits at 1-4 week intervals (except of BP>180/110 mmHg)
- Diagnosis confirmed by out of office BP measurement
Traditional manual BP measurement
- Mainstay of BP measurement
- Limited by lack of medical staff
- Inability to assess circadian variation
- Increase white-coat HTN diagnosis leading to over-diagnosis & over-treatment of HTN
Automated office BP measurement
- Decrease white-coat response
- Prediction of cardiovascular events - 3 to 5min period of quiet rest
- 2 to 3 BPs which are averaged
BP: Out of office: home monitoring & ambulatory monitoring
Home BP monitoring
- Improved motivation in self-care
- Increase adherence to anti hypertensive medications
- Take at least 2 readings 1 min apart in morning before taking medications & in evening before supper
Ambulatory BP monitoring
- Valuable tool for measuring BP variation day & night in patients with CKD
- Superior to office-measured BP to predicting CKD progression & cardiovascular risk
BP: initial evaluation: description & rules
Measure BP in both arms, preferably simultaneously. If consistent ≠ between arms >10 mmHg in repeated measurements, use arm with higher BP
- If ≠ >20 mmHg consider further investigation
Rules
- Back supported
- No talking during & between measurements
- Cuff it fit arm size (small, usual, large)
- Arm bare & resting. Mid-arm at heart level
- Feet flat on floor
- Validated electronic upper arm cuff or manual auscultatory
- Quiet room, comfortable temperature
- No smocking, coffee, exercise for 30 min
- Empty bladder
- Relax for 3-5min
- Take 3 measurements at 1min intervals
- Use average of last 2 measurements
BP: values
Tableau
PULSE ASSESSMENT: ≠ types of measure, why?, ≠ values, how measure
- Estimate with pulse
- Measure with smart watch or electrocardiogram - Measure with belt which measure HR
- Stethoscope & listen pulse during 1 min at least
- To assess patient’s pulse rate & to assess strength, regularity & character of pulse
- Pulse measured at several points in body. Points are where artery situated under skin, where it compressed against bone, allowing us to feel each beat
Tableau for values
- Wash hands to prevent cross-infection & explain what you are about to do
If you’ve been active or had stimulant like nicotine/caffeine in last 20min, you’ll need to wait at least 5-20min before taking pulse
Place tips of first & second finger on inside of patient’s wrist (radial pulse)
Press gently against pulse
Defintion heart rate
= how fast heart contracting at given time (bpm)
Definition pulse rate
= Number of times blood flows in arteries
2 ≠ types of cardiovascular measurements
Echocardiogram
Electrocardiogram
ECHOCARDIOGRAM: def, how to assess, description
D: = type of ultrasound scan to look at heart, structures & nearby blood vessels
To assess
- Myocardial thickness
- Mobility & competence of heart valves
- Dimensions of heart chambers
- Blood flow direction
- General systolic function: assessment of EF & velocity of myocardial shortening
- Changes on cardiac chambers: diseases that increase end- diastolic volume
- Valve insufficiency or stenosis
ELECTROCARDIOGRAM: how work
Sensors attached to skin used to detect electrical signals produced by heart each time it beats
ECG: Electrophysiology: 3 ≠ steps & characteristics of each
Polarization
- Heart dependent on electrical impulse to beat
- Cardiac cells at rest considered polarized
- Due to charged ions inside cell membrane (sodium & potassium) => more negative charge inside cell membrane & more positive charge outside cell membrane
Depolarization
- Once electrical impulse discharged
- Ions cross cell membrane & cell becomes depolarized
- More positive charge inside cell & more negative charge outside cell => systole, muscles contract
Repolarization
- When cell fully depolarized, it attempts to return to its resting state in process called repolarisation
- Electrical charges in cell reverse & return to normal
- More positive outside cell membrane
- More negative inside cell membrane => diastole, muscles relax
≠ phases of cardiac cycle
Schema
ECG: Einthoven’s triangle: def & ≠ leads
= imaginary formation of 3 limb leads in triangle used in electrocardiography, formed by 2 shoulders & pubis
Bipolar Limb Leads (Frontal Plane):
- Lead I
- Lead II - Lead III
Augmented Unipolar Limp Leads (Frontal Plane):
Lead aVR Lead aVL Lead aVF
Unipolar chest leads (Horizontal Plane):
Leads V1, V2, V3 (Posterior Anterior) Leads V4, V5, V6 (Right Left, or Lateral)
Signs & direction of vector
Electrical vector directed towards exploring electrode in this lead & causes positive deflection (wave)
Electrical vector directed away from exploring electrode in this lead & causes negative deflection (wave)
Frontal plane: ≠ leads, name of each & direction of each
6 leads = limb leads
aVR, aVL, aVF, I, II & III aVR, aVL, aVF => unipolar I, II & III => bipolar
Read electrical forces in frontal view
Lead aVL:
= augmented vector left
- Positive electrode on left shoulder
- From this view: left atria & circumflex artery
Lead aVR:
= augmented vector right
- Positive electrode on right shoulder
- Not best view because great vessels hide other
Lead aVF:
= augmented vector foot
- Positive electrode on foot
- From this view: ventricle & RCA branches
Lead I:
- Axis goes from shoulder to shoulder
- Negative electrode placed on right shoulder
- Positive electrode placed on left shoulder
- 0° angle of orientation (Lateral wall)
- From this view: left ventricle & lateral part of heart
Lead II:
- Axis goes from right arm to left leg
- Negative electrode on shoulder
- Positive one on leg
- +60° angle of orientation (Inferior wall)
- One of the best way to see heart
Lead III:
- Axis goes from left shoulder to right or left leg
- Negative electrode on left shoulder
- Positive electrode on right or left leg
- +120 degrees angle of orientation (Inferior wall)
- RCA & right ventricle
Transverse plane: number & name of leads + characteristics
6 leads = precordial leads (chest)
- V1-V6
- Read electrical forces in transverse plane
- Unipolar
ECG: 7 steps for analysis
- Step 1: Determine rhythm (regular vs irregular)
- Step 2: Determine rate
- Step 3: Evaluate P waves (shape & size)
- Step 4: Measure PR interval duration
- Step 5: Measure QRS duration
- Step 6: Evaluate T wave
- Step 7: Evaluate ST segment (normal, elevated or depressed)
ECG: types of arrhythmia & characteristics
- Sinus tachycardia >100bpm
Pain, anxiety, hypovolemia, congestive heart failure; severe lung disease
or sign of hyperthyroidism - Sinus bradycardia < 60bpm
Early stages of acute myocardial infarction, variation in vagal tone,
intrinsic sinus node disease; it can cause fainting - Respiratory sinus arrhythmia
Variation in heart rate associated with breathing
ECG: segments & intervals: ≠ types of segment & description of each
PR interval = atrial impulse from SA-AV normal between 0,12-0,22 s
QRS complex = ventricular depolarization normal between 0,06-0,12s
QT interval = time for ventricles to contraction & to full relaxation-normal 0,36-0,44s
ST segment = represents end of ventricular depolarization & beginning of ventricular repolarization
- Become elevated or depressed
- Important to determine STEMI & N-STEMI
- ST-elevation myocardial infarction
P-wave = first component of normal ECG waveform
- Represents atrial depolarization (electrical impulse through atria)
- Immediately after depolarization atria contract
- Precedes QRS complex
- Duration 0.06 to 0.12 s
T-Wave: Represents ventricular repolarization - Location – follows S wave
- Configuration is round & smooth
- Duration 0.10 to 0.25s
Respiratory sinus arrhythmia: def & characteristics
= heart rate variability in synchrony with respiration
- Normal phenomenon
- Relates to increase in heart rate with inspiration & decrease during expiration
ECG patho: ≠ patho
AV block
Atrial fibrillation
Atrial flutter
Ventricular fibrillation
Ventricular extrasystole
Ventricular tachycardia
Asystole
AV BLOCK: description & common cause
- AVN dysfunction = set of diseases occurring when partial or total block of impulse conduction through AVN: condition known as atrioventricular block
- Most common cause = idiopathic fibrosis of conduction system Z
ATRIAL FIBRILLATION: description & causes
- Loss of coordinated atrial contraction
- Atrial Rate: 300 – 400/ min
- Irregular ventricular rate (120-180 bpm)
- Causes: Hypertension & DM; Lung diseases
- Reduced cardiac output & formation of atrial thrombus increased risk of mortality
ATRIAL FLUTTER: description, frequency
- Results from rapid circuit occurring most commonly in right atrium
- Frequency: 250-350 bpm
- Reentrant arrhythmia - reentrant circuit runs around tricuspid valve
- ECG flutter waves - Regular pace
VENTRICULAR FIBRILLATION: description
- Disorganized heart rhythm with multiple excitable areas in ventricles showing large variations in depolarization & repolarization
- = rapid disorganized ventricular arrhythmia, resulting in no uniform ventricular activation or contraction, no cardiac output & no recordable blood pressure
- Disorganized & ineffective contraction
- Impaired pump function (no cardiac output)
VENTRICULAR EXTRASYSTOLE: description, types & frequency
= extra heartbeats begining in one of heart’s 2 lower pumping chambers (ventricles). Disrupt regular heart rhythm, sometimes causing sensation of fluttering or skipped beat in chest
- Types: parasystolic & coupled
- Frequency: single, couplets, bigeminy, trigeminy
- Important to note that 3 or + consecutive PVCs are classified as ventricular tachycardia
VENTRICULAR TACHYCARDIA: description
= heart rhythm problem (arrhythmia) caused by irregular electrical signals in lower chambers of heart (ventricles)
- Rapid heartbeat prevents heart chambers from properly filling with blood
- Heart may not be able to pump enough blood to body
ASYSTOLE: description
= cardiac arrest without electrical activity
- High-quality CPR should be continued with minimal (less than 5 seconds) interruption. CPR should not be stopped to allow for endotracheal intubation
TREATMENT OF ECG PATHO
- pacemaker: heart beats too slowly or it pauses, causing fainting spells or other symptoms. Used to prevent or treat heartbeat that is too fast or irregular
- cardioversion to correct heartbeat too fast (tachycardia) or irregular (fibrillation)
Indications: atrial fibrillation, atrial flutter, ventricular & supra ventricular tachycardia
Heart rate variability: def, type of measurement & changes
= physiological phenomenon of variation in time interval between heartbeat
- Measured by variation in beat-to-beat interval
- HRV Changes = has been shown to be predictor of mortality in cardiovascular disease patients
