PHA 4107 Lecture Notes - Lecture 12: Diastolic Heart Failure, Cardiomyopathy, Afterload
12 Jul 2018
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The heart pumps blood into circulation >>blood pressure >> tissue perfusion. Heart failure: affects 600,000 canadians & 5 million americans, common causes, ischemic heart disease, cardiomyopathy, valvular disease, hypertension, two types, systolic dysfunction, diastolic dysfunction. Symptoms of heart failure: left ventricular (lv) failure, pulmonary congestion >> dyspnea, decrease tissue perfusion >> fatigue, right ventricular (rv) failure, peripheral edema, abdominal discomfort (liver, nausea (gi tract) Compensatory mechanisms in heart failure: short-term: beneficial, long term: increase load on the failing heart >> accelerating heart failure. Drug therapy for heart failure: goals of therapy, improve symptoms, slow/reverse adverse cardiac remodelling, prolong survival. Diuretics (plasma volume) beta blockers (sympathetic nervous system & ras) angiotensin inhibitors. Cardiomyocytes are the cells in the heart responsible for contraction. Ca2+ is they key mediator of cardiomyocyte contraction. > increase contractility (inotropy: digoxin, dobutamine, milrinone. Isolated from leaves of foxglove (digitalis) plant: used for over 200 years in the treatment of heart failure.
