Week 2 Cardiac

What is the relationship between systolic pressure and stroke volume?

Higher systolic pressure leads to decreased stroke volume

Which factor influences preload by contributing to ventricular wall tension at the end of diastole?

Atrial kick

What does the Frank-Starling mechanism state about the relationship between ventricular end-diastolic volume (preload) and stroke volume?

The heart will eject a greater stroke volume if it is filled to a greater volume at the end of diastole

What is afterload in the context of ventricular function?

The force that the ventricle must overcome to eject its stroke volume

How do increases in afterload affect the Frank-Starling curve and stroke volume?

Increases in afterload shift the curve down and to the right, decreasing stroke volume

What is contractility defined as in the context of cardiac physiology?

The intrinsic strength of the heart muscle

Which event takes place during diastole in the cardiac cycle?

Relaxation and passive filling of the ventricles with blood from atria

What does Wigger's diagram depict?

Pressure waveform due to atrial systole, ventricular contraction, and pressure buildup from venous return before AV valve opens again

Which type of hypertrophy is expected in response to mitral regurgitation?

Eccentric hypertrophy

What is the normal mitral valve area?

$4-6$ cm2

Which condition is a cause of mitral stenosis?

Lupus

What is the goal for heart rate in the anesthetic management of mitral stenosis?

Low normal

What is the pathophysiological effect of chronic mitral regurgitation on the left ventricle?

Dilating and increasing end-diastolic volume

Which condition is a cause of aortic regurgitation?

Rheumatic heart disease

What is the expected effect of aortic regurgitation on the left ventricle?

Dilation and eccentric hypertrophy

"Fast and forward" is a goal in the anesthetic management of which condition?

Mitral regurgitation

What is the expected effect of aortic stenosis on ventricular thickness?

Thickening with decreased compliance

What does the acronym 'SAD' represent in the context of aortic stenosis?

Syncope, angina, dyspnea

What is the primary role of Bachmann's bundle in the heart's conduction system?

Preferential path for electrical activation of the left atrium

What is the role of Purkinje fibers in the heart's conduction system?

Rapidly conduct the action potential to myocytes throughout the ventricles

What is the main function of the SA node in the heart's conduction system?

Generates the action potential leading to depolarization of all other cardiac muscle cells

Which part of the heart serves as the link between atrial and ventricular depolarization?

AV node

What occurs as a result of dysfunction in the left bundle branch of the heart's conduction system?

Excess widths of QRS > 0.12

Which part of the heart plays a role in atrial fibrillation and interatrial block?

Bachmann's bundle

What is the major function of the bundle of His (AV bundle) in the heart's conduction system?

Conducts action potential to right and left bundle branches

What is the significance of gap junctions in the heart's conduction system?

Allows spread of action potentials between myocardial cells

What occurs during systole in the cardiac cycle?

Contraction and tension development

What is the primary function of isovolumetric relaxation in the cardiac cycle?

Relaxation of the ventricular myocardium

What does the pressure-volume loop provide an assessment of?

Integrity of cardiac valves

What happens when LV pressure exceeds LA pressure but is less than aortic pressure in the cardiac cycle?

Mitral valve closes

Which phase of the cardiac cycle is characterized by a period of rapid ejection of blood from the ventricle?

Ejection

What happens when LV pressure falls below aortic pressure in the cardiac cycle?

Aortic valve closes

What is the primary factor responsible for LV dysfunction when EF < 40%?

Low ejection fraction (EF)

What is the primary indicator used to calculate stroke volume in the pressure-volume loop?

$EDV - ESV$

What is the primary determinant of resting membrane potential (RMP) in cells?

Potassium

What happens to the RMP when serum potassium (K+) decreases?

RMP becomes more negative

What initiates the depolarization of the cell membrane?

Voltage-gated sodium channel opening

What is the main function of the Sodium-Potassium ATPase (pump) in cardiac cells?

Restores ionic balance towards RMP

What is the characteristic feature of the SA node's resting membrane potential (RMP)?

-55 to -60 mV RMP

What is responsible for the slow depolarization known as 'pacemaker potential' in the SA node?

Sodium influx

What is the rate of inherent conduction for atrial pacemakers (SA node)?

60-100 bpm

What are the typical rates of conduction for Purkinje fibers?

<20 bpm

What is the hallmark of right bundle branch block (RBBB) on an ECG?

Widened and upwardly deflected QRS complex in lead V1

Which phase of the ventricular muscle action potential is characterized by the opening of voltage-gated L-type Ca++ channels?

Phase 2

What is the resting membrane potential (RMP) of the ventricular muscle cell?

-90 mV

During which phase of the action potential is the cell easier to depolarize?

Threshold potential

What is the absolute refractory period in the context of action potentials?

Time during which an action potential may not be evoked, even if elicited by a stimulus

What ion is the myocyte permeable to, but not to other electrolytes or proteins?

Potassium (K+)

What differentiates the action potentials of different types of heart cells?

Shape of the action potential

What phenomenon refers to the internal voltage at which the cell depolarizes and exhibits an all or none response?