Cardio Anatomy Questions Flashcards
What are the three muscular sheets of the intercostal muscles?
Intercostalis externa, internus, and intimus
What is the nerve supply to the intercostal muscles?
Corresponding intercostal nerves (ventral ramus of a thoracic nerve)
What is the blood supply to the anterior upper six intercostal spaces?
Branches of internal thoracic artery
What is the blood supply to spaces 7-9 anteriorly?
Branches of musculo-phrenic artery
- Additional Information: The lower two spaces (10-11) are devoid of anterior intercostal arteries
What is the posterior intercostal blood supply to the upper two spaces?
Superior intercostal arteries
What is the posterior blood supply to spaces 3-11?
Descending thoracic aorta
What ribs is the heart located between?
2-5
What is another name for the visceral layer of serous pericardium?
Epicardium
During a surgery, the surgeon must ligate the arterial end to control hemorrhage. Which sinus would be used in order to do so?
Transverse Sinus
- Additional Information: space separating the arterial and venous ends of the heart
What is the function of the auricles?
Increase atrial volume
What is the name of the structure that encircles the junction of the atria and ventricles?
Coronary sulcus
What type of muscles line the atria?
Pectinate muscles
What ridges the walls of the ventricles?
Trabeculae carneae
- Additional Information: Papillary muscles project into the ventricular cavities
Which vessel leaves the right ventricle?
Pulmonary trunk (Pulmonary arteries)
Which vessel leaves the left ventricle?
Aorta
What is responsible for anchoring the AV Valve cusps to papillary muscles?
Chordae tendineae
Which valves prevent backflow into the atria when the ventricles contract?
Atrioventricular valves (AV Valves) – Include tricuspid on right on mitral on left
Which valves prevent backflow into the ventricles when the ventricles relax?
Semilunar valves (aortic and pulmonary)
Blood begins in the right atrium and passed through what valve to enter the right ventricle?
Tricuspid valve
The most common cause of infective endocarditis in IV drug users is S. aureus. Which valve is most frequently involved?
Tricuspid valve
From the right ventricle, how does blood flow through the heart to get to the lungs?
Right ventriclepulmonary semilunar valvepulmonary trunkpulmonary arteries Lungs
From the lungs, blood travels through the pulmonary valves into the left atrium. How does blood return to systemic circulation?
Left atriumbicuspid valveleft ventricleaortic semilunar valveaorta systemic circulation
Which circuit, pulmonary or systemic, is shorter?
Pulmonary
Which circuit, pulmonary or systemic, is higher pressure?
Systemic
Which coronary artery supplies the whole right atrium, most of the right ventricle, and posterior inferior 1/3 of ventricular septum?
Right coronary artery
What is the nerve supply to the heart?
Cardiac plexus (sympathetic and parasympathetic fibers)
A patient presents with a wide pulse pressure and machinery type murmur. What is the suspected diagnosis?
Patent Ductus Arteriosus (PDA)
What node generates impulses for the heart?
SA (sinoatrial) node
The impulses through the heart pause at what node?
AV (atrioventricular) node
What conducts impulses through the interventricular septum?
Bundle branches of His
What depolarizes the contractile cells of both ventricles?
Purkinje fibers
What defines orthostatic hypotension?
> 20 mmHg decrease in SBP or > 10 mmHg decrease in DBP
- Additional Information: If heart rate increases by 15 bmp, decreased circulatory volume is likely the cause of the orthostatic hypotension
What medication has been proven to prolong a patient’s life when they have been diagnosed with coronary disease? What is the mechanism of action?
Beta blockers
Mechanism of action: (i) Decreased oxygen demand due to the reduction in heart rate, blood pressure, and contractility, and the consequent relief of ischemic chest pain.
(ii) Increases threshold of ventricular fibrillation
Digoxin, a class V antiarrhythmic drug, works in what way?
Direct action on cardiac muscle. Indirect action on cardiovascular system via autonomic nervous system.
- Additional Information: Used in supraventricular tachycardia (SVT)
Adenosine, a class V antiarrhythmic drug, works in what way?
Slows conduction through AV Node
- Additional Information: Used in supraventricular tachycardia (SVT)
Amiodarone is what type of drug?
Potassium channel blocker – prolongs action potential – Antiarrhythmic Class III
A patient has irregularly irregular heartbeat. This heart rhythm is the most common cause of what?
Atrial fibrillation – most common cause of embolic CVA (stroke)
- Additional Information: Recall CHADS2 Criteria
Congestive heart failure (1 pt); Hypertension (1 pt); Age > 75 (1 pt); Diabetes Mellitus (1 pt); S2 Stroke, TIA, Thrombus (2 pts)
High risk and warfarin therapy recommended: >2 points; Moderate risk and warfarin or aspirin: 1 point; Low risk and no treatment or aspirin: 0 points
This disease is genetic in nature, more common in Asian men, and causes syncope, ventricular fibrillation, and sudden death (often during sleep).
Brugada syndrome
Loop diuretics leave patients more susceptible to problems with what, than do thiazide diuretics?
Electrolytes
Diuretics can increase susceptibility to what disease, which is identified by negatively birefringent crystals?
Gout, by increasing uric acid levels
A 47 year old woman has been treating her HTN with lisinopril for 15 years. In
the past, she has only experienced a cough which she dealt with knowing that the drug helped her
HTN. However, she presents today to the ED with symmetrically swollen lips and no history
that indicates this is an allergic reaction. What do you believe is the cause and can she be placed
on an ARB instead? What alternative medicines can she be given?
Lisinopril (an ACE-I) is the likely cause. No ARBs due to cross reactivity.
Alternative medicines include diuretics (HCTZ), channel blockers, or beta blockers.
Because of the negative inotropic effects of calcium channel blockers, who should
they be used cautiously in?
Answer: Patients with cardiac dysfunction
Describe the 5 classes of anti-arrhythmic drugs.
I – Sodium channel blockers (decrease conduction velocity)
- Ia: Quinidine, procainamide – prolong repolarization
- Ib: Lidocaine, phenytoin – shortens repolarization
- Ic: Flecanide – minimal effect on repolarization, widens QRS
II – Beta blockers (propranolol, metoprolol, esmolol)
III – Potassium channel blockers
IV – Calcium channel blockers (Non-dihydropyridines, verapamil, diltiazem) V – Others: Adensoine
Contraction of heart muscle is known as what?
Systole
The volume of blood pumped by each ventricle in one minute is known as what?
Cardiac output
Cardiac Output = Heart rate x Stroke Volume
How is stroke volume defined?
End diastolic volume – End systolic volume
What three man factors affect stroke volume?
Preload (degree of stretch of cardiac muscles before contraction), contractility (contractile strength at a given muscle length), and afterload (pressure that must be overcome for ventricles to eject blood)
What does hypertension do to afterload?
Increases it
How is end diastolic volume defined?
Volume of blood in each ventricle at the end of ventricular diastole
How is ejection fraction defined?
(Stroke Volume / End Diastolic Volume) x 100
A normal ejection fraction is usually greater than what percentage?
55-60%
What might you hear on physical exam in a patient with congestive heart failure?
S3 heart sound
On an EKG, what does the P wave correspond to?
Depolarization of the SA Node
On an EKG, what does the QRS complex correspond to?
Ventricular depolarization
On an EKG, what corresponds to ventricular repolarization?
T Wave
On an EKG, what corresponds to atrial repolarization?
Nothing. It is masked by the larger QRS complex.
Is the QRS narrow or wide with bundle branch blocks?
Wide (> 0.12 seconds) because of slower conduction
What leads reveal bundle branch blocks?
V1 and V6
- Additional Information:
Left BBB: RsR’ in V6; deep S in V1
Right BBB: rSR’ in V1; wide S wave in V6
A new left bundle branch block on EKG is highly suspicious for what?
A new MI
What EKG finding may be found in patients with long-standing hypertension?
Left ventricular hypertrophy
V1 or V2 leads: Deep 2 wave; V5 or V6: Tall R wave
V1 (S) + V5 (R) > 33 mm represents LVH
On EKG, what two leads are considered when determining if there is right or left axis deviation?
Leads I and AVF
In normal sinus rhythm, which lead is it normal to have an inverted P wave?
aVR
What is the first line treatment for a patient with symptomatic bradycardia?
Atropine
- Additional Information: Because excess vagal stimulation is the cause of most bradycardia rhythms, anticholinergic atropine is 1st line.
An ECG reveals a “saw tooth” pattern. What is this known as?
Atrial flutter
What is the treatment for tosades de pointes?What is the treatment for tosades de pointes?
IV Magnesium