Cardiac Physiology

Question 1

Layers of the Heart

Answer 1

Pericardium

Epicardium
Myocardium (thickest)
endocardium

Question 2

S1 Heart Sound

Answer 2

Initial closing of mitral and tricuspid valves

Question 3

S2 Heart Sound

Answer 3

Closure of Aortic and Pulmonic Valves

Question 4

S3 Heart Sound

Answer 4

Produced during passive filling of left ventricle when blood strikes a compliant left ventricle. Physiologic? Athletes and Individuals <40

Question 5

S4 Heart Sound

Answer 5

Occurs during active filling LV when atrial contraction forces blood into a noncompliant left ventricle.

Question 6

Location of Heart Sounds

Answer 6

Aortic - Second intercostal space, right sternal border
Pulmonic - Second intercostal space, left sternal border
Tricuspid - Fifth intercostal space, left sternal border
Mitral - fifth intercostal space, mid clavicular.

S3 and S4 is heart on mitral border.

Question 7

Cardiac Conduction

Answer 7

SA - 60-100
AV - 40-60

Right Bundle Branch

Left Bundle Branch:

1. Left anterior fascicle
2. Left posterior fascicle

Purkinje Fibers - 15-40

Question 8

Systolic Murmurs

Answer 8

Mitral Regurgitation (Common new finding after inferior MI) / Aortic Stenosis

Question 9

Diastolic Murmurs

Answer 9

Pulmonary Regurgitation / Mitral Stenosis

Question 10

Isolated Posterior Wall MI

Answer 10

Depressions in V2-V4 only. Normal posterior MI will shows depressions in V2-V4 with associated inferior lead ST changes.

Question 11

Which leads to which artery/EKG tracing?

Answer 11

II, III, aVF = Inferior leads / RCA
V1-V4 - Anterior wall, LAD (V1, V2 - can be considered septal)
V5, V6, I, aVL, - Lateral leads, Left circumflex branch

Question 12

Systemic Approach to EKG

Answer 12

1. Check V1 for BBB
2. Start a 1 and look through leads. II and aVL are twins. Reciprocal.

Question 13

Left Ventricular Hypertrophy Signs EKG

Answer 13

Kissing QRS

R wave in V1 and V6 added up:
>35mm diagnostic for LVH

R-wave in aVL higher than 11mm

aVF higher than 20mm

Question 14

Early Repolarization Signs on EKG

Answer 14

“fish hook” - Early (benign) repolarization. Younger adults/African Americans

Question 15

Osborn Waves signs on EKG

Answer 15

J wave (Osborn wave) . Seen in hypercalcemia. Many times secondary to hyperparathyroidism.

Question 16

Pericarditis signs on EKG

Answer 16

ST elevations throughout the entire 12-Lead (Dressler Syndrome)

PR interval is downsloping

Sharp Chest Pain, Radiates to the base of neck, unable to lay supine

Question 17

Aberrant Conduction (LBBB)

Answer 17

V1 >.120 or 120ms. Need to look at scarbossa to definitively diagnose OMI.

Downward deflection = Left
Upward deflection: Right

Question 18

Raised ICP signs on EKG

Answer 18

High sympathetic tone:

Increased ICP leads to deep inverted T waves. Higher than 10 mm.

Question 19

Device-Paced Rhythm signs on EKG

Answer 19

Pacer Spikes
Global Wide QRS complexes

Question 20

False OMI EKG acronym

Answer 20

LEOPARD

Left Ventricular Hypertrophy
Early Repolarization
Osborn Waves
Pericarditis
Abberant Conduction (BBB)
Raised ICP
Device Paced Rhythm

Question 21

Wellen’s Syndrome

Answer 21

Normal to slight elevation in cardiac markers
Biphasic T-waves in V2-V3

> 75% patients will proceed to anterior OMI in a few weeks.

Type 1: Deep biphasic inverted T waves
Type 2: Deep inverted symmetric T waves

Question 22

aVR Diagnostic

Answer 22

If aVR and V1 have st elevation with associated depressions in V3-V6. It is diagnostic for left main insufficiency.

Question 23

Left Bundle Branch Block

Answer 23

Sgarbossa Criteria

Concordant STE >1mm = 5 points
STD V1-V3 >1mm = 3 points
Discordant STE >5mm = 2 points

3 points for likely OMI

Question 24

De Winters T-Wave

Answer 24

Tall prominent T-waves
Upsloping ST-segment depression >1mm
ST-segment elevation in aVR

Potential Left Main Insufficiency.

Question 25

Acronym for unique EKG findings

Answer 25

WALDO Wellen's Syndrome aVR Diagnostic Left Bundle Branch Block De Winters Syndrome Out of hospital ROSC

Question 26

SHIP

Answer 26

Subtle Inferior/Lateral Hyper-acute T-Waves Isolated Posterior OMI

Question 27

Beta-Blockers

Answer 27

Antagonists of the beta receptors in the heart and lungs. Decreased inotropic, chronotropic, dromotropic effects on the heart. May cause bronchospasm

Question 28

Esmolol

Answer 28

Beta-Blocker - Blood pressure and heart rate. Antagonizes Beta-1 adrenergic receptors of heart and lungs Contra: Bronchospasms/Asthma Bradycardia, AV blocks, cardiogenic shock, CHF

Question 29

Labetalol

Answer 29

Antihypertensive. Selective Alpha 1 and non-selective beta antagonist.

Question 30

Calcium Channel Blockers

Answer 30

Blocking Ca++ into vascular smooth muscle - Vascular smooth muscle relaxation, especially at coronary arteries. Slowing impulses through SA and AV nodes. Vasodilation

Question 31

Dopamine

Answer 31

2-5 mcg/kg Primarily beta stimulation Increased Q, contractility, and renal perfusion. 5-10 - Alpha/beta Loss of renal action

Question 32

Norepinephrine

Answer 32

Stimulates alpha receptors.

Question 33

Inodilators

Answer 33

Dobutamine, milrinone Beta 1 and beta 2 effects Decrease peripheral vascular resistance Milrinone increases intracellular calcium leading to improved myocardial contractility and stroke volume.

Question 34

Methylene Blue

Answer 34

Nitric Oxide Inhibitor Combats the vasodilation from nitric oxide released secondary to pro-inflammatory mediator release.

Question 35

Vasodilators

Answer 35

Hydralazine Dilates arterial system Decreases afterload PIH/HTN Nitroglycerin Dilates primarily venous system - decreases preload Dilates arterial in higher doses.

Question 36

Nitroprusside

Answer 36

Relaxes vascular smooth muscle Dilates arterial and venous system. Decreased afterload and preload. Precautions: Pregnancy. Watch for cyanide toxicity.

Question 37

Heparin

Answer 37

Accelerates formation of antithrombin III, thrombin complex, inactivates thrombin and prevents conversion of fibrinogen to fibrin.

Question 38

TPA

Answer 38

Alteplase, Activase, t-PA ischemic stroke STEMI PE

Question 39

Axis Deviation

Answer 39

Normal Axis - 0-90 Left Axis Physiological - 0-30 Left Axis Pathological 31 to -90 Right axis - +90 - +180 Left - points away Right - points together Normal - up together LVH, LBBB, Inferior MI, Paced Rhythm, Left anterior fascicular block

Question 40

Right Axis

Answer 40

Chronic - RVH, COPD, Lateral Wall MI Acute - Misplaced Leads PE Sodium Channel blocker (Lidocaine, Procainamide Amiodarone Quinidine), TCA, cocaine