Misc + Physiology Flashcards
Absent A waves
(JVP Waveform)
AF, sinus tachycardia
Flutter waves
Atrial Flutter
Prominent A waves
First-degree AV block
A wave
Atrial Contraction
X descent
Atrial relaxation
Large A wave
Increased RA pressure: TS, R) atrial myxoma, pulomonary HTN, PS
Cannon A waves
AV disassociation, VT
Phase 0 (Ventricular AP)
Rapid depolarisation (influx of Na through L-Type Ca channels)
Phase 1 (Ventricular AP)
Transient repolarisation (inactivation of Na channels, activation of outward K channels)
Phase 2 (Ventricular AP)
Plateau - outward K balanced by inward Ca
Phase 3 (Ventricular AP)
Inactivation of Ca channels, ongoing eflux of K
Phase 4 (Ventricular AP)
Stable resting membrane potential
Ion associated w/ TdP
Associated w/ early after depolarisation, during phase 2 or 3- due to inhibition of the outward eflux of K ions or increased influx of Ca
Cardiac muscle contraction
Calcium influx during Phase 2 (Plateau phase) attaches to Troponin C, causing tropomyosin to detach from myosin-binding sites on actin and myosin –> cross-bridge –> contraction
What is Electrical Alternans on ECG? What does it indicate?
Variation in amplitude of QRS complexes. Indicated pericardial effusion.
Which NSAIDs are cardioprotective?
Non-selective COX inhibitors
> Aspirin
> Naproxen
Preload definition
Myocardial sarcomere length just prior to systole - approximated by EDV
Afterload definition
Left ventricular wall stress during onset of systole
Left ventricular fractional shortening
% change in LV internal dimensions between systole and diastole
What is not affected by preload?
A) EF
B) ESV
C) End systolic fractional shortening
D) Peak systolic pressure
E) Cardiac output
B) ESV
V wave
Passive filling of RA with close tricuspid valve during ventricular contraction
Y descent
Atrial emptying
Cardiac pathology secondary to carcinoid syndrome
Valvular heart disease
Types of Cardiac Amyloidosis
- Transthyretin amyloidosis (ATTR amyloidosis)
- Light chain amyloidosis (AL amyloidosis)
- Serum amyloid A amyloidosis (AA)
Imaging modalities to investigate cardiac amyloidosis
- TTE
- Cardiac MRI
- NM Bone Scan
AL Amyloidosis Treatment
- Treat underlying malignancy
- Treat complications - AF & conduction disease
- Transplant - if malignancy treated
- Avoid ACEi/BB/CCB due to risk of hypotension
- Avoid digoxin due to risk of toxicity
ATTR Amyloidosis Treatment
- Treat complications - AF & conduction disease
- Disease-specific therapy
> Tafamidis - prevents cleavage of transthyretin tetramers, reduced amyloid deposit. Reduces mortality.
> Difunisal - NSAID prevents cleavage of amyloid tetramers, improves neuropathy sx - Transplant - if isolated to heart
