Cardiac Physiology Flashcards
Layers of the Heart
Pericardium
Epicardium
Myocardium (thickest)
endocardium
S1 Heart Sound
Initial closing of mitral and tricuspid valves
S2 Heart Sound
Closure of Aortic and Pulmonic Valves
S3 Heart Sound
Produced during passive filling of left ventricle when blood strikes a compliant left ventricle. Physiologic? Athletes and Individuals <40
S4 Heart Sound
Occurs during active filling LV when atrial contraction forces blood into a noncompliant left ventricle.
Location of Heart Sounds
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.
Cardiac Conduction
SA - 60-100
AV - 40-60
Right Bundle Branch
Left Bundle Branch:
- Left anterior fascicle
- Left posterior fascicle
Purkinje Fibers - 15-40
Systolic Murmurs
Mitral Regurgitation (Common new finding after inferior MI) / Aortic Stenosis
Diastolic Murmurs
Pulmonary Regurgitation / Mitral Stenosis
Isolated Posterior Wall MI
Depressions in V2-V4 only. Normal posterior MI will shows depressions in V2-V4 with associated inferior lead ST changes.
Which leads to which artery/EKG tracing?
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
Systemic Approach to EKG
- Check V1 for BBB
- Start a 1 and look through leads. II and aVL are twins. Reciprocal.
Left Ventricular Hypertrophy Signs EKG
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
Early Repolarization Signs on EKG
“fish hook” - Early (benign) repolarization. Younger adults/African Americans
Osborn Waves signs on EKG
J wave (Osborn wave) . Seen in hypercalcemia. Many times secondary to hyperparathyroidism.
Pericarditis signs on EKG
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
Aberrant Conduction (LBBB)
V1 >.120 or 120ms. Need to look at scarbossa to definitively diagnose OMI.
Downward deflection = Left
Upward deflection: Right
Raised ICP signs on EKG
High sympathetic tone:
Increased ICP leads to deep inverted T waves. Higher than 10 mm.
Device-Paced Rhythm signs on EKG
Pacer Spikes
Global Wide QRS complexes
False OMI EKG acronym
LEOPARD
Left Ventricular Hypertrophy
Early Repolarization
Osborn Waves
Pericarditis
Abberant Conduction (BBB)
Raised ICP
Device Paced Rhythm
Wellen’s Syndrome
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
aVR Diagnostic
If aVR and V1 have st elevation with associated depressions in V3-V6. It is diagnostic for left main insufficiency.
Left Bundle Branch Block
Sgarbossa Criteria
Concordant STE >1mm = 5 points
STD V1-V3 >1mm = 3 points
Discordant STE >5mm = 2 points
3 points for likely OMI
De Winters T-Wave
Tall prominent T-waves
Upsloping ST-segment depression >1mm
ST-segment elevation in aVR
Potential Left Main Insufficiency.
Acronym for unique EKG findings
WALDO
Wellen’s Syndrome
aVR Diagnostic
Left Bundle Branch Block
De Winters Syndrome
Out of hospital ROSC
SHIP
Subtle Inferior/Lateral
Hyper-acute T-Waves
Isolated Posterior OMI
Beta-Blockers
Antagonists of the beta receptors in the heart and lungs.
Decreased inotropic, chronotropic, dromotropic effects on the heart.
May cause bronchospasm
Esmolol
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
Labetalol
Antihypertensive.
Selective Alpha 1 and non-selective beta antagonist.
Calcium Channel Blockers
Blocking Ca++ into vascular smooth muscle
- Vascular smooth muscle relaxation, especially at coronary arteries.
Slowing impulses through SA and AV nodes.
Vasodilation
Dopamine
2-5 mcg/kg Primarily beta stimulation
Increased Q, contractility, and renal perfusion.
5-10 - Alpha/beta
Loss of renal action
Norepinephrine
Stimulates alpha receptors.
Inodilators
Dobutamine, milrinone
Beta 1 and beta 2 effects
Decrease peripheral vascular resistance
Milrinone increases intracellular calcium leading to improved myocardial contractility and stroke volume.
Methylene Blue
Nitric Oxide Inhibitor
Combats the vasodilation from nitric oxide released secondary to pro-inflammatory mediator release.
Vasodilators
Hydralazine
Dilates arterial system
Decreases afterload
PIH/HTN
Nitroglycerin
Dilates primarily venous system - decreases preload Dilates arterial in higher doses.
Nitroprusside
Relaxes vascular smooth muscle
Dilates arterial and venous system. Decreased afterload and preload.
Precautions: Pregnancy. Watch for cyanide toxicity.
Heparin
Accelerates formation of antithrombin III, thrombin complex, inactivates thrombin and prevents conversion of fibrinogen to fibrin.
TPA
Alteplase, Activase, t-PA
ischemic stroke
STEMI
PE
Axis Deviation
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
Right Axis
Chronic - RVH, COPD, Lateral Wall MI
Acute - Misplaced Leads
PE
Sodium Channel blocker (Lidocaine, Procainamide Amiodarone Quinidine), TCA, cocaine
