Cardiac Physiology 1.2

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

Widened QRS complex and upwardly deflected in lead V1 (correct)

Deep S wave in V5/V6

Narrow QRS complex and downwardly deflected in lead V1

Large R’ wave in V5/V6

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

Phase 0

Phase 3

Phase 1

Phase 2 (correct)

What is the resting membrane potential of the ventricular muscle?

-90 mV (correct)

-50 mV

-70 mV

-60 mV

During which phase of the action potential is there a restoration of membrane potential towards the resting state following depolarization?

Phase 3 Signup and view all the answers

What is the threshold potential for the initiation of an action potential in excitable cells?

-70 mV Signup and view all the answers

Which phase of the cardiac action potential is characterized by a prolonged plateau phase?

Phase 2 Signup and view all the answers

What is the absolute refractory period of a cardiac myocyte?

-90mV to -60mV Signup and view all the answers

Which feature is indicative of a right ventricular impulse block?

Large R’ wave in V1/V2 Signup and view all the answers

"The difference in electrical potential between the inside and outside of the cell" refers to:

"Resting membrane potential" Signup and view all the answers

"The restoration of membrane potential towards RMP following depolarization" is known as:

"Repolarization" Signup and view all the answers

What do pressure-volume loops provide an assessment of?

Systolic and diastolic function as well as cardiac valve integrity Signup and view all the answers

During the period of isovolumic relaxation (diastole), what happens to the left ventricular (LV) volume?

It remains unchanged Signup and view all the answers

What is the formula to calculate stroke volume (SV) based on the pressure-volume loop?

$SV = EDV - ESV$ Signup and view all the answers

Which period of the cardiac cycle represents ventricular ejection (systole)?

Period of ventricular ejection Signup and view all the answers

In a pressure-volume loop, where is diastolic blood pressure (DBP) measured?

Where the aortic valve opens Signup and view all the answers

What is the normal ejection fraction (EF)?

60-70% Signup and view all the answers

What is a characteristic of eccentric hypertrophy?

Dilated ventricle with thin wall Signup and view all the answers

What is the treatment for mitral stenosis?

$Na^+$ restriction, diuretics, $eta$ blockers, and surgical or percutaneous interventions Signup and view all the answers

What condition promotes transvalvular pressure gradient dependent on cardiac output, heart rate, and diastolic time?

Mitral stenosis Signup and view all the answers

What does critical mitral stenosis correspond to in terms of valve area?

0.5 cm2 Signup and view all the answers

What is the goal for preload in mitral stenosis?

Maintain normal to increased preload (LVEDV) Signup and view all the answers

What is the primary role of the AV node in the heart's electrical conduction system?

To conduct the action potential from the SA node to the ventricles Signup and view all the answers

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

To rapidly conduct the action potential to myocytes throughout the ventricles Signup and view all the answers

Which structure allows for the spread of action potentials between myocardial cells in the heart?

Gap junctions Signup and view all the answers

During normal sinus rhythm (NSR), which pathway is preferentially responsible for electrical activation of the left atrium?

Bachmann’s bundle Signup and view all the answers

What is the purpose of the delay in propagation through the AV node?

To allow for simultaneous contraction of the atria and ventricles Signup and view all the answers

What is a hallmark sign of dysfunction in the left bundle branch?

Excess widths of QRS > 0 Signup and view all the answers

Which component of the heart's conduction system conducts electrical impulses from the AV node down the interventricular septum?

AV bundle (Bundle of His) Signup and view all the answers

What is responsible for triggering the initial depolarization in the heart's conduction system?

SA node Signup and view all the answers

What is the relationship between ventricular end-diastolic volume (EDV) and stroke volume (SV) according to the Frank-Starling Mechanism?

As EDV increases, SV increases Signup and view all the answers

What is the force that the ventricle must overcome to eject its stroke volume?

Intraventricular pressure during peak systole Signup and view all the answers

What effect does an increase in afterload have on the Frank-Starling curve?

Shifts the curve down and to the right Signup and view all the answers

What is contractility in relation to the heart muscle?

The intrinsic strength of the heart muscle Signup and view all the answers

During which phase of the cardiac cycle do the left and right ventricles contract and eject blood into the aorta and pulmonary artery?

Ejection Signup and view all the answers

What happens during isovolumetric relaxation in the cardiac cycle?

LV pressure falls below LA pressure Signup and view all the answers

What accounts for approximately 15-20% of ventricular filling during rapid filling in the cardiac cycle?

Atrial systole Signup and view all the answers

What does the Pressure-Volume Loop tell us about in the cardiac cycle?

Relationship between ventricular volume and ventricular pressure Signup and view all the answers

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

Potassium Signup and view all the answers

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

RMP becomes more negative Signup and view all the answers

Which ion is responsible for depolarizing the cell when the resting membrane potential (RMP) approaches threshold potential?

Sodium Signup and view all the answers

What is the main purpose of the sodium-potassium ATPase (pump) in cells?

To remove Na+ ions from the cell Signup and view all the answers

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

-60 mV Signup and view all the answers

What is the function of ectopic pacemakers in cardiac physiology?

Assume pacemaker responsibility in SA node disorder Signup and view all the answers

What is the effect of idiopathic fibrosis on the conduction system in cardiac physiology?

Impairs transmission of action potentials from atria to ventricles Signup and view all the answers

What is the formula for cardiac output (CO)?

$CO = HR imes SV$ Signup and view all the answers

Which factor determines the preload or end-diastolic volume (EDV) in cardiac physiology?

Left atrial pressure at end of diastole Signup and view all the answers

What happens to stroke volume (SV) if systolic pressure is increased in cardiac physiology?

SV decreases Signup and view all the answers

What is the primary goal for anesthetic management in mitral stenosis?

Normal to increased preload, avoid tachycardia, and maintain contractility Signup and view all the answers

What is the main effect of aortic regurgitation on the left ventricle (LV)?

LV dilation and eccentric hypertrophy Signup and view all the answers

Which valve pathology is associated with a history of long asymptomatic period before the development of symptoms?

Aortic regurgitation Signup and view all the answers

What is the primary surgical management option for chronic aortic regurgitation?

Surgical aortic valve replacement Signup and view all the answers

What are the primary goals in aortic insufficiency/regurgitation management?

Normal to increased preload, decreased afterload, and low heart rate Signup and view all the answers

What is the main effect of mitral regurgitation on left ventricular compensation over time?

Dilating and increasing end-diastolic volume (EDV) Signup and view all the answers

Which valve pathology is associated with the triad of syncope, angina, and dyspnea in valve areas less than 1cm2?

Aortic stenosis Signup and view all the answers

What are the primary goals in mitral regurgitation/insufficiency management?

High preload, decreased afterload, and low heart rate Signup and view all the answers

What characterizes the wall of the left ventricle (LV) in aortic stenosis?

Thick LV wall with decreased compliance and narrowed chamber Signup and view all the answers