Human Heart Function and Blood Circulation

Heart Function and Blood Pressure

• The heart is the hardest working muscle in the body.
• On average, it pumps approximately 9500 liters of blood daily.
• With each contraction, the apex beats against the chest wall, creating the apical pulse.
• The heart has a dual pumping action, where the right side pumps blood to the lungs and the left side pumps blood to the body simultaneously.
• Blood flows through the heart in a rhythmic, smooth motion in one direction (ideally).

Orthostatic Hypotension

• Defined as a sustained reduction in systolic pressure by at least 20 mmHg or a drop in diastolic pressure by at least 10 mmHg within 3 minutes of standing or a head-up tilt > 60 degrees.
• Symptoms include light-headedness, dizziness, blurred vision, fatigue, and headache.
• It is an effective indicator of blood volume depletion.

Blood Pressure

• High Blood Pressure: Systolic BP > 130, Diastolic BP > 80.
• Low Blood Pressure: Systolic BP < 60.
• Symptoms of Low Blood Pressure include light-headedness, dizziness, blurred vision, fatigue, and headache.
• Low Blood Pressure is an effective indicator of blood volume depletion.

Heart Function and Blood Pressure

• The heart is the hardest working muscle in the body.
• On average, it pumps approximately 9500 liters of blood daily.
• With each contraction, the apex beats against the chest wall, creating the apical pulse.
• The heart has a dual pumping action, where the right side pumps blood to the lungs and the left side pumps blood to the body simultaneously.
• Blood flows through the heart in a rhythmic, smooth motion in one direction (ideally).

Orthostatic Hypotension

• Defined as a sustained reduction in systolic pressure by at least 20 mmHg or a drop in diastolic pressure by at least 10 mmHg within 3 minutes of standing or a head-up tilt > 60 degrees.
• Symptoms include light-headedness, dizziness, blurred vision, fatigue, and headache.
• It is an effective indicator of blood volume depletion.

Blood Pressure

• High Blood Pressure: Systolic BP > 130, Diastolic BP > 80.
• Low Blood Pressure: Systolic BP < 60.
• Symptoms of Low Blood Pressure include light-headedness, dizziness, blurred vision, fatigue, and headache.
• Low Blood Pressure is an effective indicator of blood volume depletion.

Jugular Vein Distention

• Occurs when blood backs up in the heart or superior vena cava, causing increased pressure and bulging of the vein.

Measuring Jugular Vein Distention

• Hold a vertical ruler on the angle of Louis (sternal angle).
• Align a straight edge on the ruler to form a T.
• Adjust the horizontal straight edge to the level of pulsation.

Characteristics of JVD

• Jugular veins distend when the patient lies supine.
• Jugular veins flatten when the patient is in a sitting position.

Auscultation of Heart Sounds

• Heart sounds are typically listened to at four sites: aortic, pulmonic, Erb's point, and tricuspid/mitral
• To auscultate heart sounds, ask the patient to breathe comfortably and not speak
• Assume a semi-Fowler's or supine position to facilitate listening

Heart Sounds

• S1 (systolic sound) is high-pitched and dull in quality, sounding like 'lub'
• S1 occurs due to the closure of tricuspid and mitral valves
• S1 can be remembered as "LUB = PUMP"

Diastolic Sound

• S2 (diastolic sound) is high-pitched and best heard with the diaphragm
• S2 sounds like 'dub'
• S2 occurs due to the closure of aortic and pulmonic valves
• S2 can be remembered as "DUB = RELAX"

Carotid Artery Assessment

• Patient position: Sitting
• Initial inspection: Obvious arterial pulsations on both sides of the neck
• Palpation:
  • Separate palpation of each carotid artery
  • Use index and middle fingers
  • Location: Medial edge of the sternocleinomastoid muscle
• Patient positioning during palpation:
  • Raise chin slightly
  • Keep head straight or slightly away from the artery
• Importance of breathing:
  • Note changes in bruit with breathing
  • Indicative of sinus arrhythmia

Auscultation

• Use the bell of the stethoscope
• Place over each carotid artery
• Listen for a blowing sound (bruit)

Inspection and Palpation Techniques

• To facilitate palpation, turn the patient onto their left side to move the heart closer to the chest wall.

Normal Heart Position

• In individuals 7 years and older, the Point of Maximal Impulse (PMI) is palpable at the fifth intercostal space at the left midclavicular line.

Abnormal Heart Position

• In the presence of serious heart disease, the PMI shifts to the left of the midclavicular line due to an enlarged left ventricle.
• In chronic lung disease, the PMI may shift to the right of the midclavicular line as a result of right ventricular enlargement.

Inspection and Palpation Steps

• Stand to the patient's right to inspect and palpate the precordium with the patient in a supine position.
• Note any visible pulsations and exaggerated lifts.
• Closely inspect the apex area.
• Palpate for pulsations using the proximal half of four fingers together and alternating with the ball of the hand at all anatomical landmarks.

The Precordium

• The precordium covers the heart and great vessels and extends from the 2nd to 5th intercostal space.

Inspection and Palpation Techniques

• To facilitate palpation, turn the patient onto their left side to move the heart closer to the chest wall.

Normal Heart Position

• In individuals 7 years and older, the Point of Maximal Impulse (PMI) is palpable at the fifth intercostal space at the left midclavicular line.

Abnormal Heart Position

• In the presence of serious heart disease, the PMI shifts to the left of the midclavicular line due to an enlarged left ventricle.
• In chronic lung disease, the PMI may shift to the right of the midclavicular line as a result of right ventricular enlargement.

Inspection and Palpation Steps

• Stand to the patient's right to inspect and palpate the precordium with the patient in a supine position.
• Note any visible pulsations and exaggerated lifts.
• Closely inspect the apex area.
• Palpate for pulsations using the proximal half of four fingers together and alternating with the ball of the hand at all anatomical landmarks.

The Precordium

• The precordium covers the heart and great vessels and extends from the 2nd to 5th intercostal space.