Clinical Cardiology notes year 3 PDF

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Rebekah Mercer year 3 clinical practice cardiology notes...

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Clinical Cardiology notes year 3 CHEST XRAYS MADE EASY Details -

patient name, sex, DOB, no. date taken projection (PA unless stated otherwise): look at the medial margins of scapula – if at edges of chest wall then it is PA and if hanging in it is AP

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Rotation – spinous process of thoracic vertebrae should be midway between medial ends of clavicle Inspiration: diaphragms should lie at level of 6th ribs ant. Right hemidiaphragm is usually higher than left due to liver Picture area Exposure – can you see lower thoracic vertebral bodies through heart (if not then poorly exposed)

RIPE

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Airway Breathing Circulation Diaphragm/disability Extra

PA is when xrays shoot from back to plate in front. If too sick to stand up AP (ant to posterior)

Cardiac Investigations Introduction Standard calibration: will be printed in the bottom left hand corner  

Speed 25mm/s Gain 11mm/mV

Each small square is 1mm wide and = 0.04 seconds. X5 small squares = one large square Each large square is 5mm wide and = 0.2 seconds hence x5 large squares = 1 second

Amplitude is influenced by:    

Myocardial mass – increased left ventricular hypertrophy Net vector of depolarisation Thickness and properties of intervening tissues eg pericardial fluid can result in small amplitude waveform Distance between electrode and myocardium – low amplitude in obese people but high amplitude in hypertensive people.

ECG electrical deflection:   

When impulse is towards electrode = +ve/upward deflection When impulse is away from electrode = -ve/downward deflection When wave is at right angles to electrode an equiphasic deflection is produced

ECG cables x10 = 12 lead ECG. Central reference point  can calculate required info to produce 12 electrical views of heart. 2 methods 1. Bipolar leads I, II and III using 1 +ve and 1 -ve 2. Unipolar leads (augmented and chest) using 1 +ve electrode and calculating notional central reference terminal in heart Einhoven’s triangle: standard bipolar leads

Augmented unipolar leads: aVR will always be -ve in normal conduction and if limb leads are placed correctly

Anatomical relationships:    

II, III and aVF = inferior V1-4 = anterior I, aVL, V5 and V6 = lateral V1 and aVR = right atrium and left cavity

Rhythm strip is usually lead 2 as this is where p waves are best seen.

Chest leads (precordial) 1. 2. 3. 4. 5. 6.

4th intercostal space to right of sternum 4th intercostal space to left of sternum Directly between V2 & V4 5th intercostal space, midclavicular line Level with V4 at L ant axillary line Level with V5 at midaxillary line (midpoint of armpit)

Intervals and rates: HR controlled by ANS but has innate system independent controlled by specialised tissue of SA node, AV node, bundle of his and purkinje fibres. Normal intervals: 

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PR: time from SA node to beginning of ventricular depolarisation. Measured from beginning of P wave to beginning of QRS complex. (should technically called the PQ interval as measured up to start of q wave) Usually 3-5 small squares (0.12 – 2.0 secs) QRS: time taken for impulse to depolarise all ventricular myocardium. 2-3 small squares (0.08 – 0.12 secs) QT: total time of ventricular electrical activity ie depolarisation and repolarisation. Varies according to HR. 0.35-0.43 secs. Isoelectrical line is baseline on which all waveforms should begin and return to

When rhythm is regular: 300 large squares per minute. Rhythm is regular count no. of large squares between 2 QRS complexes and divide into 300. HR = 300/x = bpm When rhythm irregular: 30 large squares correspond to 6 secs. Count number of QRS complexes in 30 large squares and multiply by 10. Sinus bradycardia:      

R-R intervals constant and regular All waveforms present and there is 1 P wave to each QRS complex Rate 40...