Diastolic function and gallops Flashcards
Define diastolic dysfct
o Impaired myocardial relaxation
o Restriction to LV filling
o incr LV filling pressures
Define diastolic failure
CHF w normal systolic fct
o Forward failure: restricted filling => decr LV volume
o Backward failure: incr LV filling pressure => incr LA pressure
Interactive components of diastolic fct
o Myocardial relaxation
o Atrial contraction
o Rapid/slow filling phases
o Loading conditions
o Pericardial sac
o Elastic properties of the heart
Diastolic filling abn
o Impaired/delayed relaxation: hypertrophy, ischemia
incr LV pressure at beginning of diastole
LV filling delayed => incr contribution of atrial contraction to filling
o decr compliance: fibrosis, infiltrative process, hypertrophy, structural abnormalities
Stiff LV: pressure incr rapidly as filling occurs
incr LV end diastolic pressures
IVRT
- AoV closure => MV valve opening: no change in LV volume while decr pressure and myocardial relaxation
o decr rate of relaxation => incr IVRT
Transmitral valve flow
- Bernoulli equation do not apply for MV inflow (viscous/internal forces, flow acceleration)
o Pressure differentials reflected in LV inflow profiles
o Peak flow velocity determined by gradient LA => LV
Phases of LV filling
o Rapid filling phase: LV < LA pressure => rapid inflow => LA = LV pressures
Most of LV filling
Peak E wave = LA to LV pressure gradient at beginning of diastole
o Slow filling phase: deceleration of flow velocity as pressure equilibrates.
Deceleration time of E wave
Diastasis period
o Filling 2nd to atrial contraction: small acceleration of flow
Peak A wave = LA to LV pressure gradient at end of diastole
Impaired relaxation pattern
o decr E, incr A waves => decr E/A ratio
o incr deceleration time => early predictor of HCM in cats
o incr IVRT
TDI
- Less dependent on preload: E’ and A’
- Normal feline TDI
o E’ >0.72m/s
o E:E’ <8.07m/s
PV flow
- Pulmonary venous flow is pulsatile and continuous
- LA filling occur during ventricular systole: S wave
o Can be biphasic
o Velocity related to mean LAP - Early diastole: blood is pulled from LA to LV => decr LAP
o Blood moves passively from PV => LA => LV = D wave - Late diastole: atrial contraction => incr LAP => reversal of pulmonary vein flow: Ar wave
o End diastolic LAP
o LA fct
o LV compliance
o HR/rhythm - Canine:
o Ar wave velocity incr w age
o Ar wave duration decr w age - Feline:
o S wave velocity: incr w age and incr HR
o Ar wave duration decr w age
Pseudonormal pattern
- Normal mitral inflow profile despite diastolic dysfct
- LA pressure continue to incr as diastolic dysfct progresses
o incr early filling => incr E wave - Restrictive filling pattern: E/A ratio >1
Restrictive pattern
- Severly impaired relaxation
- Severely decr compliance
- incr LV filling pressures
S3 gallop
- Acceleration of blood in early filling phase => abrupt maximal distension => vibration of LV walls
o Restrictive physiology: rapid reach of ventricular elasticity limit
o Protodiastolic gallop (early diastole)
o Shortly after peak E wave, during deceleration - Can have respiratory variation: LV S3 ↑ w expiration, RV S3 ↑ w inspiration
Causes S3 gallop
o High CO: L => R shunt, anemia, hyperT4
o Rapid ventricular filling: MR, TR, AI
o decr diastolic filling + residual ventricular volume: CHF
- Pathologic in dogs/cats, normal in massive hearts (cows, horses)
S4 gallop
- Active ventricular filling following atrial contraction => forceful ejection in already distended/non compliant ventricle
o Presystolic gallop (end diastole)
o Pathologic in dogs/cats
o Abnormal ventricular compliance
RV: heard on TV area, louder at inspiration
LV: heart on MV area, louder at expiration
o incr A wave
