Day 6.1 Cardio Flashcards
Causes of increased ESR
Infection (osteomyelitis) Inflammation (e.g. temporal arthritis, polymyalgia rheumatica) Cancer Pregnancy SLE
Causes of decreased ESR
Sickle cell (altered shape)
Polycythemia (too many)
CHF (unknown why)
Toxic side effects of TCA use
Convulsion
Coma
Cardiotoxicity (Tri C’s)
Repsi depression and hyperpyrexia
What anti-seizure drugs are used to treat bipolar disorder?
Lamotrigine
Carbamazepine
Valproate (Valproic acid)
Coronary arteries
RCA and LCA come off of aorta.
LCA gives LAD and CFX
RCA gives PDA (80%) and Acute marginal artery
What does the LAD supply?
Apex and anterior interventricular septum
What does CFX supply?
Posterior LV
What does PDA supply?
aka posterior interventricular artery
Posterior septum
Inferior part of LV
What does the AMA (acute marginal artery) supply?
RV
What supplies the SA and AV nodes?
RCA
Where does PDA arise from?
80% arise from RCA
20% arise from CFX (from LCA)
Most common site of coronary artery occlusion
LAD (anterior interventricular septum)
This is called an anterior wall MI
When do coronary arteries fill?
Diastole
Effects of LA enlargement
LA is most posterior part of heart.
Enlgmt causes dysphagia d/t compression of esophageal nerve
hoarseness d/t compression of recurrent laryngeal nerve (vagus)
CO eqn
CO = SV x HR
Fick principle eqn
CO = rate of O2 consumption / [arterial O2 content - venous O2 content]
MAP eqn
MAP = CO x TPR (P = Q x R)
MAP = 1/3 systolic + 2/3 diastolic
Pulse pressure
PP = systolic - diastolic
proportional to SV: if SV increases, PP increases.
SV eqn
SV = EDV- ESV
SV = CO / HR
What variables affect SV?
Contractility
Afterload
Preload
Increased contractility = increased SV
Increased afterload = decreased SV
Increased preload = increased SV
4 things that make contractility increase
and therefore SV increases too
- Catecholamines (B1 receptor)- increased activity of Ca2+ pump in SR
- Increased intracellular Ca2+
- Decreased extracellular sodium (so Na+/Ca2+ exchger works less, more Ca2+ stays inside cell)
- Digitalis (Increased intracellular Na+, so Na+/Ca2+ exchgr works less, more Ca2+ stays inside). aka digoxin.
5 things that make contractility decrease
and therefore SV decreases too
- B1 blockade
- Heart failure
- Acidosis
- Hypoxia/hypercapnia
- Non-dihydropyridine Ca2+ chnl blockers: Verapamil
What happens to CO during exercise?
Initially it goes up, bc of increased SV.
After prolonged exercise, CO increases as a result of increased HR.
What happens to CO if heart rate is too high?
Diastolic filling is incomplete (not enough time to fill) so CO decreases
eg in ventricular tachycardia
What is preload?
Preload = ventricular EDV
What is afterload?
Afterload = mean arterial prs (MAP)
proportional to TPR
Do venodilators affect preload or afterload?
They decrease preload (blood pools in veins, so less goes back to heart)
e.g. Nitroglycerin
Do vasodilators affect preload or afterload?
They decrease afterload bc they dilate arteries
Eg hydralazine
Afterload = Arterial!
In what conditions does SV increase?
Anx (bc catecholamine surge)
Exercise (bc increased preload, also increased catecholamines)
Pregnancy (higher blood vol, so higher preload)
What happens to SV in heart failure
decreases
What increases myocardial O2 demand?
Increased afterload (increased arterial prs)
Increased contractility
Increased HR
Increased heart size (increased wall tension)
Diff bt non-dyhydropyridine Ca2+ chnl blockers and dihydropyridine
Non-dyhydropyridine Ca2+ chnl blockers = verapamil. Works at heart.
Dyhydropyridine work at blood vessels.
Drugs that decrease O2 demand in heart attack
ACE inhibitors and ARBs decrease afterload
Beta-blockers (metoprolol) decrease HR and contractility
In what condition is there increased heart size?
Hypertrophic cardiomyopathy.
Higher risk for heart attack and sudden cardiac death since this increases O2 demand on the heart.
What does the starling curve show?
That the force of contraction is proportional to the initial length of cardiac muscle fiber (preload).
Plots CO or SV against Ventricular EDV or preload
EF eqn
EF = SV / EDV
EF = [EDV -ESV] / EDV
What is EF normally?
> = 55%
It’s an index of ventricular contractility
Eqn for resistance, prs, flow
P = Q x R (MAP = CO x TPR)
Eqn for resistance
R = 8nl / [pi x r^4]
8.viscosity.length / pi.radius to the 4th
directly prop to visc, inversely prop to radius^4
What determines velocity, physiologically?
Mostly the hematocrit. As you increase velocity, you increase resistance. Viscosity is increased in: polycythemia (too many RBCs) hyperproteinemic states (mult myeloma) hereditary spherocytosis
Which vessels account for most of the TPR?
Arterioles
they regulate capillary flow
Resistance of vessels in a series
Rseries = R1 + R2 + R3…
Resistance of vessels in parallel
Rparallel = 1/R1 + 1/R2 + 1/R3…
Cardiac cycle Phase 1
Isovolumetric contraction
- period bt mitral valve closing and aortic valve opening
- highest O2 consumption
- this is systole
Cardiac cycle Phase 2
Systolic ejection
- period bt aortic valve opening and closing
- lose SV
Cardiac cycle Phase 3
Isovolumetric relaxaing
-period bt aortic valve closing and mitral valve opening
Cardiac cycle Phase 4 & 5
4: Rapid filling (just after mitral opens)
5: Reduced filling (just before mitral valve closing)
- gain the SV
S1
Mitral and tricuspid closure
Loudest at mitral area
point bt phase 5 and phase 1
S2
Aortic and pulmonary valve closure
loudest at left sternal border
point bt phase 2 and 3
S3
In early diastole during rapid ventricular filling phase (phase 4)
assoc w increased filling prs
more common in dilated ventricles
normal in kids and prego