吉林大学：《药理学》课程PPT教学课件（七年制）Treatment of Congestive Heart Failure

Treatment of Congestive Heart Failure

Treatment of Congestive Heart Failure

OVERVIEW OF CONGESTIVE HEART FAILURE Congestive heart failure (CHF)is a condition in which the heart is unable to pump sufficient blood to meet the needs of the body.CHF can be caused by an impaired ability of the cardiac muscle to contract or by an increased workload imposed on the heart

OVERVIEW OF CONGESTIVE HEART FAILURE ◼ Congestive heart failure (CHF) is a condition in which the heart is unable to pump sufficient blood to meet the needs of the body. CHF can be caused by an impaired ability of the cardiac muscle to contract or by an increased workload imposed on the heart

Three classes of drugs 1)vasodilators that reduce the load on the myocardium; 2)diuretic agents that decrease extracellular fluid volume; 3)inotropic agents that increase the strength of contraction of cardiac

Three classes of drugs ◼ 1) vasodilators that reduce the load on the myocardium; ◼ 2) diuretic agents that decrease extracellular fluid volume; ◼ 3) inotropic agents that increase the strength of contraction of cardiac

PHYSIOLOGY OF MUSCLE CONTRACTION the cardiac muscle cells are interconnected in groups that respond to stimuli as a unit,contracting together whenever a single cell is stimulated

PHYSIOLOGY OF MUSCLE CONTRACTION ◼ the cardiac muscle cells are interconnected in groups that respond to stimuli as a unit, contracting together whenever a single cell is stimulated

Action potential the cells of cardiac muscle show a spontaneous,intrinsic rhythm generated by specialized "pace-maker" cells located in the sinoatrial (SA),and atrioventricular (AV)nodes. The cardiac cells also have an unusually long action potential,which can be divided into five phases

Action potential ◼ the cells of cardiac muscle show a spontaneous, intrinsic rhythm generated by specialized "pace- maker" cells located in the sinoatrial (SA), and atrioventricular (AV) nodes. ◼ The cardiac cells also have an unusually long action potential, which can be divided into five phases

PHASE 0:FAST UPSTROKE PHASE 1:PARTIAL REPOLARIZATION ·to8am） rapid phase of repolarization ·ae产channels are 1)inactivation of Nachannels. ·mec2 uiniine Cell Na+ Na +50 PHASE 2:PLATEAU Ca++ Ca+ Ca+ Time (seconds) PHASE 3:REPOLARIZATION ●Cat+-channels close. Ca PHASE 4:FORWARD CURRENT ·99C8o sodium K K potential

Cardiac contraction The force of contraction of the cardiac muscle is directly related to the concentration of free (unbound) cytosolic calcium

Cardiac contraction ◼ The force of contraction of the cardiac muscle is directly related to the concentration of free (unbound) cytosolic calcium

Sources of free intracellulan calcium The first is from outside the cell,where opening of voltage-sensitive calcium channels causes an immediate rise in free cytosolic calcium. -The second source is the release of calcium from the sarcoplasmic reticulum and mitochondria,which further increases the cytosolic level of calcium

Sources of free intracellular calcium ◼ The first is from outside the cell, where opening of voltage-sensitive calcium channels causes an immediate rise in free cytosolic calcium. ◼ The second source is the release of calcium from the sarcoplasmic reticulum and mitochondria, which further increases the cytosolic level of calcium

Removal of free cytosolic calcium If free cytosolic calcium levels were to remain high,the cardiac muscle would be in a constant state of contraction, rather than showing a periodic contraction.Mechanisms of removal include two alternatives

Removal of free cytosolic calcium ◼ If free cytosolic calcium levels were to remain high, the cardiac muscle would be in a constant state of contraction, rather than showing a periodic contraction. Mechanisms of removal include two alternatives

Removal of free cytosolic calcium Sodium-calcium exchange: Uptake of calcium by the sarcoplasmic reticulum and mitochondria:

Removal of free cytosolic calcium ◼ Sodium-calcium exchange: ◼ Uptake of calcium by the sarcoplasmic reticulum and mitochondria: