Cardiac Muscle Dysfunction and Failure Flashcards
Causes and Types of Cardiac Muscle Dysfunction
Hypertension CAD Cardiac arrythmias Rapid or slow arrhythmias can impair functioning of left and/or right ventricle Renal Insufficiency Cardiomyopathy Heart Valve Abnormalities Congenital/Acquired Heart Disease pericardial effusion or myocarditis Pulmonary embolism Pulmonary hypertension Spinal cord injury Age-related changes
Renal Insufficiency
Acute or chronic insufficiency produces fluid overload
Primary treatment is to decrease reabsorption of fluid from kidneys
Diuretic
Cardiomyopathy
Contraction and relaxation of myocardial muscle fibers are impaired
Primary causes of cardiomyopathy:
pathological process in heart muscle
Secondary causes of cardiomyopathy:
result of systemic disease processes
Types of cardiac myopathy:
dilated
hypertrophic
restrictive
Dilated:
myocardial damage resulting from mitochondrial damage
Causes of dilated myopathy:
long term alcohol abuse pregnancy cigarrete smoking infections systemic hyertension
Hypertrophic:
rapid ventricular emptying
high ejection fraction
Causes of hypertrophic myopathy:
genetic
malalignement of myocardial fibers
Restrictive:
diastolic dysfunction with unimpaired contractile function
Causes of restrictive myopathy:
myocardial fibrosis
ventricular hypertrophy
Pericardial Effusion or Myocarditis
Injury to pericardium of heart may cause inflammation of pericardial sac (pericarditis)
Pericarditis leads to pericardial effusion
Cardiac tamponade
elevated intracardiac pressures, limited ventricular diastolic filling, reduced SV
Pulmonary Embolism
Resulting dysfunction is due to elevated pulmonary artery pressures that increase right ventricular work
Pulmonary Hypertension
Defined by mean pulmonary artery pressure (mPAP)
Abnormal if >25 mm Hg or in patients with COPD if >20 mm Hg
Congenital and Acquired Heart Disease
Result of altered embryonic development of normal structure or failure of structure to develop
Two most common Congenital and Acquired Heart Disease:
congenital bicuspid aortic valve and leaflet abnormality associated with mitral valve
Influences of stretch
Atrial contribution to ventricular filling Total blood volume Body position Intrathoracic pressure Intrapericardial pressure Venous tone Pumping action of skeletal muscle
Stage 1 CHF:
redistrubution
cardiomegaly
broad vascular pedicle
PCWP 13-18 mmHg
Stage 2 CHF:
interstitial edema
Kerley lines
PCWP 18-25 mmHg
Stage 3 CHF
alveolar edema
PCWP greater than 35mmHg
consolidation
pleural effusion
Alpha-adrenergic receptors
Alpha1 – marginally increases inotropic effect
Alpha2 – activates inhibitory G protein, which decreases inotropic effect
Beta-adrenergic receptors
Beta2 stimulation promotes vasodilation of capillary bed and muscle relaxation of bronchial tracts
Beta1 stimulation increases heart rate and myocardial force of contraction
Symptoms of CHF:
dyspnea
paroxysmal nocturnal dyspnea
orthopnea
Dyspnea
breathlessness or air hunger
Paroxysmal nocturnal dyspnea
unexplained episodes of shortness of breath occur in supine position
Orthopnea
development of dyspnea in recumbent position
Breathing patterns of CHF:
rapid respiratory rate at rest with quick and shallow breaths
Heart sounds of CHF:
S3 indicates a noncompliant left ventricle and is associated with CHF
Rales
Pulsus alternans
mechanical alteration of femoral or radial pulse
