Download Heart Failure

Cardiac Cycle
1. Ventricular Systole
- Isovolumetric contraction
- Ventricular ejection
2. Ventricular Diastole
- Isovolumetric ventricular relaxation
- Ventricular filling: Rapid inflow
Diastasis
Atrial systole
Checkpoints
1.
2.
3.
4.
심실, 심방, 동맥내 압력.
심실내 용적변화.
판막의 여닫힘 시기.
심음, EKG .
BP
Systolic
Diastolic
Ventricular volume change during cardiac cycle
EDV
SV
ESV
- Stroke Volume (SV) = EDV - ESV
- Ejection fraction = SV/EDV : 50 - 60 %
심실근 수축성의 지표
심음 청진 부위
• Normal Heart Sound: S1, S2, (S3)
• Abnormal Heart Sound (Murmur)
- timing: systolic/diastolic/continuous
- area
심근수축의 기본 형태
Preload
Afterload
Preload dependence
EDV 에 해당, venous return에 의해 결정됨.
Afterload : Aortic Pressure에 해당
심장의 작업곡선
근수축의
길이-장력 관계
(length-tension)
심장에서는
압력-용적 관계
(pressure-volume)
로 나타냄
Animal Experiment
Measurement with Conductance Catheter
LV pressure-volume loop
LV pressure
LV pressure
LV volume
LV pressure
End
systole
End
diastole
LV volume
Regulation of myocardial performance
 Intrinsic regulation (autoregulation)
- Frank-Starling mechanism
- Rate-induced regulation
 Extrinsic regulation
- Autonomic nervous system
- Endocrine control :
adrenal medullary hormone
thyroid hormone, insulin, glucagon
- 기타: PO2, PCO2, pH
LV pressure
The effect of increasing preload
LV volume
심장의 자동조절 기전: Frank-Starling 기전
• 용적부하 (preload)
증가에 따른 반응
EDV
SV
• 압력부하 (afterload)
증가에 따른 반응
SV
EDV
SV
Contractility Indices
peak dP/dt
dP/dt/DP
systolic
ejection rate
ejection
fraction
contractility
Heart Disease, Braunwald, 5th edition
Autonomic Nervous Control
b1-adrenergic receptor
Heart
Heart
Dorsal motor nucleus Vagus nerve
(cardioinhibitory center)
Muscarinic receptor
Vagal
stimulation
Sympathetic
stimulation
Effect of autonomic nerve stimulation on SAN
Sympathetic stim.
Parasympathetic stim.
Left
Sympathetic
SV
parasympathetic Conduction velocity
Right
SV HR
HR
Effect of Autonomic Nervous System
sympathetic
parasympathetic
SA Node
AV Node
Atrial myocardium
Ventricular myocardium
Positive chronotropic
Positive inotropic
Negative chronotropic
Negative inotropic
Signal transduction of ion channel regulation
by autonomic stimulation
sympathetic
parasympathetic
b-adrenergic receptor
muscarinic receptor
Gs protein
Gi protein
Adenylyl cyclase
_
cAMP
Protein kinase A
Phospholylation of ICa & If
Activation of IKACh
Ion Channel Mechanism of Nervous System
sympathetic
parasympathetic
SA Node
ICa
If
IKACh ICa
AV Node
ICa
If
IKACh ICa
Atrial myocardium
Ventricular myocardium
ICa
ICa
Na pump
IKACh ICa
교감신경 흥분의 수축력에 대한 효과
Contractility 증가
교감신경 흥분, Ca 농도 증가 등의 조건에서 수축력 증가
Cardiac factors
Coupling factors
Heart Rate
Myocardial
Contractility
Pleload
Cardiac
Output
Afterload
Regulation of the heartbeat
- Baroreceptor reflex
- Bainbridge reflex
- Chemoreceptor reflex
- Respiratory sinus arrhythmia
- Effect of blood or electrolyte solution infusion
Coronary circulation
 extracoronary resistance
- squeezing effect of the
contracting myocardium
- left coronary flow :
early ventricular systole
에 reverse;
early diastole에 최대
 Autoregulation 발달
- change of perfusion pressure : blood flow 비교적 일정하게 유지
- metabolic demands 증가
vasoactive metabolites released from
myocardium
coronary resistance 감소
- adenosine hypothesis 가 가장 유력
Ischemic Heart Disease
관상동맥 막힘
Ischemia(허혈), Infarction(경색)
세포내 ATP 감소
KATP Channel의 활성화
활동전압 duration 짧아짐, K의 유출로 세포밖 K 농도 증가
수축 감소로 energy saving의 효과 (cardioprotective)
동시에 부정맥 발생 위험 증가 (arrhythmogenic)
Heart Failure
- 정의: Pumping capability of the heart is impaired to the point
that the tissues of the body are not adequately perfused.
- Acute or Chronic
- In chronic H. F.,
fluid retention (hypervolemia)
is accompanied.
(GFR aldosterone분비 )
right shift of
vascular function curve
C.O은 정상일 수도 있음
Fig.29-12
The effect of sympathetic stimulation on the equilibrium value of
cardiac output and central venous pressure
Fig. 29-10
Fig. 29-9
Effect of cholinergic blocker (atropine)
and adrenergic blocker (propranolol) on heart rate
Respiratory sinus arrhythmia :
inspiration - HR (vagal activity )
expiration - HR (vagal activity )
Respiratory Center
Change in
intrathoracic
pressure
Change in
lung volume
(stretch receptor)
Change in
venous return
Bainbridge
reflex
Change in
Arterial pressure
Baroreceptor
reflex
Cardiac
Vagal
Center
Heart
Rate
Intravenous infusion
Right atrial pressure
Cardiac output
Atrial receptor
stimulated
Arterial pressure
Baroreceptor reflex
Bainbridge reflex
_
+
Heart Rate
Cardiac Output (C.O)
= Stroke Volume (ml) x Heart Rate (/min)
Fig. 29-16
Left and Right Heart (Systemic vs. Pulmonary)
Fig. 29-14
Fig. 24-19
The effect of sympathetic stimulation on the equilibrium value of
cardiac output and central venous pressure
Fig. 29-10
Fig. 29-9