Cardiac Flashcards
Atrial Systole is…
The contraction of the right and left atria pushing blood into the ventricles
Atrial Diastole
The period between atrial contractions when the atria are repolarising
Ventricular systole
Contraction of the right and left ventricles pushing blood into the pulmonary artery and aorta
Ventricular diastole
period between ventricular contractions when the ventricles are repolarising
Ventricular PVCs are
Preventricular contractions characterised by: - Absent p wave - wide QRS Can occur in isolation or grouped. Serious when >6 per minute
Unifocal PVC - look the same Multifocal PVC - more than one shape. Trigeminal - every third rhytm Bigeminal every other beat Couplet - occur in pairs Triplet - three in a row
Ventricular fibrillation is characterised by
Absent p-wave and no QRS complex. Generally irregular
Pulseless emergency situation
Ventricular Tachycardia
Absent pwave, Fast rate. Wide and bizarre QRS. Run of 3 or more PVCs occurring sequentially
Atrial flutter
Saw tooth pattern - 250-350 for atrial rate. Ventricular often slower.
Atrial tachycardia
P wave- merged with T wave
150-250 bpm
Atrial fibrillation
Pwave absent or erratic
>350 but ventricular rate may be normal. If HR and BP are stable can still exercise.
if resting HR is above 115 or the patient is uncomfortable or responding poorly then stop and seek medical consult.
Abnormal heart enzymes
CK-MB - 2-4hours –> 12-24 hours –> 2-3 days
Cardiac troponin (normal <0.03) 2-4 hours –> 24-48 hours –> 14 days
CK 6 hours –> 12 hours –> 2-3 days
Preload
Tension in the ventricular wall at the end of diastole. Venous filling pressure of the left ventricle during diastole
Afterload
forces that impede the flow of blood out of the heart. Peripheral vascular pressure. Inversely proportional to stroke volume.
Stroke volume
volume of blood ejected by each contraction. Average 60-80ml.
Cardiac output
Amount of blood pumped from the left or right ventricle per minute 4.5-5L/min at rest. Product of SV and HR
Venous return.
Amount of blood returned to the right atrium each minute
S1 Heart sound
Normal, low pitch ‘Lub’ sound. Closure of the AV valves
S2 Heart sound
Normal higher pitched ‘dub’
S3 Heart sound
Abnormal - ventricular gallop. Passive flow of blood from atria during diastole.
S4 Heart sound
Abnormal - atrial gallop, ventricular filling and atrial contraction
Bruit
Abnormal blowing sound - atherosclerosis
Murmurs
Between S1 and S2 or S2 and S1 - valvar disease