Week 6 - Cardio Part 1

Question 1

Cardiac output calculation

Answer 1

Heart Rate (HR) x Stroke volume (SV)

Question 2

Normal Cardiac output

Answer 2

4-8 L/min

Question 3

Normal Stroke Volume

Answer 3

~ 70 mL per heart beat

Question 4

Define preload and afterload

Answer 4

Preload is the amount of blood in the ventricle at the end of diastole (filling pressure in the ventricle at end-diastole).

Afterload is the pressure at which the ventricle must generate to pump blood through the aortic valve into the aorta.
Also known as SVR (Systemic Vascular Resistance).
HTN causes increased afterload or SVR
Hypotension is indicative of decreased afterload

Question 5

Frank Starling Law states that

Answer 5

As left ventricular filling pressures increase (also known as the pulmonary capillary wedge pressure – PCWP), SV and CO increase.

Question 6

Etiologies of most cases of HF due to what 4 causes

Answer 6

Ischemic (CAD)
Rheumatic valvular disease
Hypertensive heart disease
COPD

Question 7

ANP and BNP come from where? and do what?

Answer 7

Atrial natriuretic peptides - from atria in response to stretch
-Leads to vasodilation

Brain (B-type) natriuretic peptides - from ventricles in response to pressure or volume overload
- protective effect by antagonizing RAAS and decreasing preload (but not enough to compensate for the effects of HF)

Question 8

Three categories of HF and their Left Ventricular Ejection fractions

Answer 8

HFpEF (Heart Failure with preserved Ejection Fraction): LVEF ≥50%

HFmEF (HF with mid-range Ejection Fraction): LVEF 41-49%

HFrEF (HF with reduced Ejection Fraction)
LVEF ≤40%

Question 9

What are Kerley B lines ?

Answer 9

fine horizontal opacified lines that represent fluid in interstitial space

Question 10

Normal BNP levels and BNP levels indicating HF

Answer 10

BNP < 100pq/ml → HF unlikely
BNP > 400pq/ml → HF highly likely

Question 11

MOA of furosemide

Answer 11

Inhibits Na/K/Cl co-transporter at thick portion of ascending loop of Henle (where ⅓ Na is reabsorbed) → inhibits Na & water reabsorption

Question 12

A/E of furosemide

Answer 12

Electrolyte abnormalities (hypokalemia, hyponatremia, hypomagnesaemia)
Hypotension
Renal dysfxn
Ototoxicity (at high doses or rapid IV administration)
Hyperuricemia/ May precipitate gout

Question 13

Quadruple Therapy Treatment for HFrEF (LVEF ≤40%) includes:

Answer 13

Beta blocker
ARNI or ACEi/ARB
MRA
& SGLT2 inhibitor

Question 14

MOA of ARNI
(ie. valsartan/sacubitril )

Answer 14

ARB: - Angiotensin receptor antagonist
- Blocking Angiotensin II binding/effects → v.d., decreases aldosterone release → decreases Na & H2O absorption → decrease BP

neprilysin Inhibitor → increases natriuretic peptides → induces vasodilation & natriuresis (Na excretion in urine)

Question 15

MOA of ACE inhibitors

Answer 15

Inhibit production of angiotensin II → vasodilation.
- Decrease aldosterone release → increases excretion of Na & H2O while retaining K+
- Suppress degradation of bradykinin (vasodilator) → increase bradykinin → increase v.d. → decrease BP
- Decrease afterload & preload
- Increase SV
- Decrease activation of SNS