Cardiac Physiology Quiz

Physiology Revision - Sem 4 CVS

• Arterial Pulse: A pressure wave traveling down arteries, felt in superficial arteries.
• Pulse Pressure: A pressure wave, felt through superficial arteries.
• Sites of Palpation: Common carotid artery, radial artery, femoral artery, tibial artery, dorsalis pedis artery. Radial pulse is found on wrist, under thumb.
• How to Palpate Radial Pulse: Place middle three fingers on the palm of forearm, above wrist and medial to brachioradialis muscle. Apply slight pressure with proximal finger to create turbulent flow. Apply high pressure with distal finger to block back arterial pulsation. Middle finger will feel pulse.
• How to Comment on Radial Pulse: Count beats per minute (rate). Determine if rhythm is regular or irregular.
• Heart Sounds: Two audible sounds, detected by stethoscope or phonocardiograph.
• Methods of Detection: Stethoscope—detects two sounds only audible with stethoscope. Phonocardiograph—records four sounds, shown on a phonocardiogram.
• Medical Stethoscope: Consists of three parts: chest piece (cone/bell for low-intensity sounds, diaphragm for high-intensity sounds), ear pieces, rubber tube (50-75 cm).
• Uses of Stethoscope: Auscultation of heart, breath, and intestinal sounds; measures blood pressure (ABP).
• Auscultatory Areas: Specific areas on the chest for listening to heart sounds (aortic, pulmonary, tricuspid, mitral valves).
• First Heart Sound (S1): Duration: 0.15 sec. Cardiac cycle relation: At the beginning of ventricular systole. Cause: Sudden closure of AV (tricuspid and mitral) valves. Characters: Soft, low-pitched (25-40 Hz). Detected by stethoscope as "Lub." Auscultatory sites: Mitral area (left 5th intercostal space at midclavicular line). Tricuspid area (left 4th intercostal space near sternum).
• Second Heart Sound (S2): Duration: 0.1 sec. Cardiac cycle relation: At the beginning of ventricular diastole. Cause: Sudden closure of semilunar valves (aortic and pulmonary). Characters: Sharp, high-pitched (50 Hz). Detected by stethoscope as "Dub." Auscultatory sites: Aortic area (2nd right intercostal space near sternum). Pulmonary area (2nd left intercostal space near sternum).
• Third Heart Sound (S3): Duration: 0.05 sec. Cardiac cycle relation: Mid part of ventricular diastole. Cause: Vibrations of relaxed ventricular wall and cusps of AV valves. Characters: Low-pitched, sometimes only heard in children. Best heard at mitral area while recumbent, leaning left.
• Fourth Heart Sound (S4): Duration: 0.03 sec. Cardiac cycle relation: Atrial systole (presystolic). Cause: Vibration of AV valve cusps due to blood rushing into ventricles. Characters: Faint, low-pitched, usually inaudible in adults and children. Detected at mitral area with abnormality.
• Heart Sounds Abnormalities: This includes Splitting of Heart Sounds (asynchronous closure of valves on both sides of the heart), Triple Rhythm (abnormal condition where 3 heart sounds resemble a galloping horse), Murmurs (abnormal noisy sounds over heart).
• Arterial Blood Pressure (ABP): Lateral force exerted by blood on artery walls. Expressed as systolic/diastolic.
• Systolic BP: Maximum pressure during ventricular systole (normally 90-140 mmHg).
• Diastolic BP: Lowest pressure during ventricular diastole (normally 60-90 mmHg).
• Pulse Pressure: Difference between systolic and diastolic pressure (normally 30-50 mmHg in adults).
• Vital Signs: Blood pressure, heart rate, respiratory rate, oxygen saturation, temperature. ABP is a vital sign.
• Factors Affecting ABP: Sex, age, emotions, exercise, hormones, gravity, race, sleep.
• Types of Sphygmomanometers: Mercury, aneroid, digital, hybrid.
• Components of Sphygmomanometer: Rubber bag in a cloth casing, rubber tubes, a valved pump for inflating/deflating the bag, a calibrated mercury scale or similar device for reading the pressure.
• Measuring Technique (Palpation): Apply cuff to upper arm. Palpate radial pulse. Inflate cuff until pulse disappears. Gradually deflate cuff and note systolic pressure (when you feel the first pulse again).
• Measuring Technique (Auscultation): Place cuff around upper arm. Place stethoscope on brachial artery. Raise manometer pressure above palpatory systolic pressure by 10-20 mmHg. Slowly deflate manometer. Note when first sound occurs (systolic pressure). Note when last sound disappears (diastolic pressure).
• Practical Notes on ABP Measurements: Ensure doctor is on the right side of subject. The subject arm should be naked. Select appropriate cuff size. Position manometer accurately.
• Advantages/Disadvantages of Measurement Techniques: Palpation is easier but less accurate (only measures systolic). Auscultation is more accurate (measures both systolic and diastolic), but requires more equipment (stethoscope).
• Hypertension (HTN): Persistent elevation of blood pressure in arteries. Classification of blood pressure is provided: Normal, Prehypertension, Stage 1 HTN, Stage 2 HTN.
• Electrocardiogram (ECG): Records electrical activity of cardiac muscle.
• ECG Apparatus: Sensitive galvanometer, Amplifier, Recording electrodes (+ve/exploring electrode connected to +ve pole of galvanometer), (-ve/indifferent electrode attached to -ve pole of galvanometer), Pen recorder, Moving paper film.
• ECG Principle: Action potentials transmitted through body fluids to skin surface. The potential differences are detected by electrodes and amplified and recorded on paper to show the wave pattern.
• ECG Leads: Particular arrangement of two electrodes to galvanometer. Types: Bipolar limb leads, Unipolar leads, leads I, II, III, aVR, aVL, aVF.
• Bipolar Limb Leads: Measure potential difference between two limbs. Lead I (RA and LA), Lead II (RA and LF), Lead III (LA and LF).
• Einthoven’s Triangle and Law: Relationship between voltage of leads I, II and III. The sum of voltages for lead I and III is equal to the voltage in lead II.
• Unipolar Limb Leads: Measure potential at one point. Use augmented limbs ( aVR, aVL, aVF) to record weaker potentials.
• Unipolar Chest Leads: Measure from V1 to V6; V1 (right 4th intercostal space), V2 (left 4th intercostal space), V3 (midway between V2 and V4), V4 (left 5th intercostal space, midclavicular line), V5 (left 5th intercostal space, anterior axillary line), V6 (left 5th intercostal space, middle axillary line).
• ECG Tracing: Pattern depends on the spread of excitation waves through the heart and on electrode/lead position.
• ECG Waves: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization), U wave (repolarization of papillary muscles—usually absent).
• P-R Interval: Time from start of P wave to start of QRS complex. Normal Duration is 0.12–0.2 seconds. Significance: Represents conductivity through AV bundle. Abnormalities: Prolonged (vagal stimulation, first-degree blocks, atrial hypertrophy); shortened (sympathetic stimulation, AV nodal rhythm); absent (complete heart block, some cases of AV nodal rhythm).
• Q-T Interval: Time from start of QRS complex to end of T wave. Normal duration is 0.4 seconds. Significance: Represents ventricular depolarization and repolarization. Abnormalities: Prolonged (hypocalcemia, ischemia); shortened (hypercalcemia, digitalis toxicity).
• S-T Segment: Measures from end of S wave to start of T wave. Normal duration is 0.12 seconds. Significance: Ventricular muscles completely depolarized (isoelectric). Abnormalities: Elevated (recent myocardial infarction, pericarditis); depressed (ischemia, ventricular extrasystoles).
• Cardiac Axis: Overall direction of the heart's electrical activity; normal axis is -30° to +90°; left axis deviation (-30° to -90°); right axis deviation (+90° to +180°).
• Determining Axis Normality/Deviation: Using lead 1, AVR and R waves and the relationships (I + aVF = II, etc)
• Other ECG information: Methods to determine heart rate using ECG paper are demonstrated; ways of determining rhythmicity from ECG are also described.

Test your knowledge on key concepts in cardiac physiology, including the significance of the Q-T interval and S-T segment duration. This quiz covers essential cardiovascular techniques and the interpretation of EKG patterns, suitable for medical and nursing students. Challenge your understanding of heart sounds and pulse techniques in the human body.