Heart Disease Etiology, Symptoms, Treatment

Heart Disease Etiology, Symptoms, Treatment

1. Systolic or Diastolic

   • Systolic
     • Decreased ability of the heart to pump out blood
       • Due to weakening of the wall of the ventricle (dilated)
         • Due to cell death
           • Resulting in a decreased ejection fraction
             • Which is due to decreased force of contraction and decreased Stroke Volume
             • Remember that EF=SV/LVEDV
               • So... decreased SV means a decreased EF
     • Caused by...
       • Heart muscle disease (Cardiomyopathy) of unknown cause
       • Decreased blood supply to heart muscle due to CAD resulting in heart cell death
       • Valvular disease
         • Regurgitation at AV valves
           • R/I increased work, increased O2 requirement, cell death
         • or Stenosis of semilunar valves
           • Ditto. Different problem, same result
       • Arrhythmia
         • Ditto. There's just not enough O2 available to allow for extra work
       • Ventricular Dilation and altered cardiac muscle contractility or
   • Diastolic
     • Decreased ability of the heart to fill
       • Due to hypertrophy of the wall of the ventricle
         • Due to increased after load
           • Resulting in a "normal" ejection fraction
             • But a decrease in blood pumped out of the heart
               • Due to a lack of space within the ventricle
             • Remember that EF=SV/LVEDV
               • So... decreased filling but the same percentage pumps out
                 • Means a "normal" EF
     • Caused by...
       • An increase in after load, as is found in Hypertension
       • Aortic Valve Stenosis
       • Cardiomyopathy
         • Hypertrophic
         • or Restrictive
         • Disease leads to decreased blood supply
           • Which leads to hypertrophy of mm and increased work
             • Which leads to an increased demand for oxygen
               • Which leads to cell death, scar tissue and restriction
                 • Which leads to a decreased blood supply
                   • and so on...

2. Can be left heart failure, or right, or both

   • Left Heart Failure
     • Blood backs up into the lungs
       • and from there into the right ventricle and so on
     • CHF
     • Symptoms
       • Forward Failure
         • Fatigue
         • Decreased urine production
         • Palpitations
       • Backward Failure
         • Lung Congestion
           • Difficulty breathing
             • and pink, foamy mucus
         • Orthopnea
         • Weight Gain
   • Right Heart Failure
     • Blood backs up into the body - usually the legs
     • Symptoms
       • Forward Failure
         • Fatigue due to CO2 levels
         • Palpitations
       • Backward Failure
         • LE Congestion
         • Jugular Vein Distension
         • Weight Gain
         • Increased urination, especially at night

3. Compensation

   • Is meant to increase Cardiac Output
     • Remember CO=SVxHR
       • normally about 5L/minute
     • in order to meet the demands of the body for more oxygen than it's getting
       • Increase SV
         • by activating the Sympathetic Nervous System
           • which eventually exhausts the heart's response to it
         • or Increase Preload
           • Remember Starling's Law
           • by activating the ADH System
             • which causes the body to retain fluids
             • which increases the work of heart, which demands more oxygen, which is unavailable, so cells die
         • or via Hypertrophy of muscle
           • Ditto - cell death
       • or Increase HR
         • by activating the Sympathetic Nervous System
           • Ditto
   • Which eventually leads to decompensation

4. First, treat with exercise, dietary changes, and HTN Meds

   • Angiotensin Converting Enzyme (ACE) Inhibitors
     • Vasodilators
       • Decrease Afterload
   • Beta-blockers
     • Block the activation of beta receptors
       • Decreasing heart's response to Sympathetic Nervous System
   • Hydrazine and Nitrates
     • Vasodilators for either arteries or veins
       • Decrease Afterload
       • Decrease preload
   • Meant to either make the heart more efficient
     • or to decrease the likelihood of structural changes

5. Later, treat the symptoms of congestion with diuretics (i.e. Aldosterone Inhibitors)

   • Decreasing fluid build-up in lungs and BP
   • Calcium Channel Blockers for Diastolic Failure
     • Decreasing smooth muscle contraction which decreases BP
     • Decreasing Heart Muscle Contraction
       • Which allows the heart to fill

6. FINALLY, for end-stage treatment

   • Ventricle Assist Device
     • Bypasses the Ventricle and pumps blood to the body
   • Pacemaker or Defibrillator
   • Stents to widen arteries
   • or Coronary Artery Bypass
   • Heart Transplantation