Cardiac Hypertrophy: Hyperkalemia

Question 1

Eccentric hypertrophy

Answer 1

Volume overload-induced cardiac hypertrophy

*Dilation as opposed to increased thickness

Question 2

Concentric hypertrophy

Answer 2

A hypertrophic growth of a hollow organ without overall enlargement, in which the walls of the organ are thickened and its capacity or volume is diminished.

*Thickening reduces systolic stress

Question 3

In concentric hypertrophy, heart wall thickens ________ (inward/outward).

Answer 3

Inward

*Heart grows inward becuase of the fibrous pericardium

Question 4

What are the results on concentric hypertrophy?

Answer 4

Reduced ventricle size

Reduced end diastolic volume

Reduced stroke volume

NOTE: There is not rue eccentric or concentric hypertrophy. The eccentric hypertrophy will cause concentric hypertrophy.

Question 5

How does ischemia result from concentric hypertrophy?

Answer 5

As thickening of the heart wall proceeds your stoke volume decreases. When ejection is low the coronary circulation decreases while ventricular muscle mass increase, this causes your heart to become ischemic. Eventually the heart can fail.

Question 6

Athletic people undergo hypertrophy. Why are their hearts fine?

Answer 6

The thickening of the wall mathches the lengthening of the ventricle

NOTE: If the thickening can’t keep up with the chamber enlargement, you are at a deficit and end up with heart failure.

Question 7

How is left venticular hypertrophy seen on an EKG?

Answer 7

• Leads V1 and V2: tall S- wave
• Leads V5 and V6: tall R- wave

Question 8

What is the possible etiology of left ventricular hypertrophy?

Answer 8

• Mitral valve disease
• Aortic valve disease
• Systemic hypertension

Question 9

What type of hypertrophy is seen in left ventricular hypertrophy? If the etiology is as seen below:

Mitral valve disease

Aortic valve disease

Systemic hypertension

Answer 9

Concentric

• You have pressure overload because the afterload is higher
• Therefore stress on the wall is induced during systole
  
  • Sacromere replication in parallel
    
    • Concentric hypertropy

Question 10

T wave inversion is also a sign of hypertrophy. Why?

Answer 10

In cardiac hypertrophy there is an increase in connective tissue that disrupts the normal progression of flow. This will affect the flow of electricity. Cardiac hypertrophy also mixes up the action potential durations, so the difference in the action potential duration between apical and basal cells becomes minimal. This causes the T wave inversion.

Question 11

What are the characteristics of an right ventricular hypertrophy ECG?

Answer 11

Leads V1 and V3: tall R wave

Leads V5 and V6: tall S wave

Question 12

What type of hypertrophy is seen in right ventricular hypertrophy? If the etiology is as seen below:

• Pulmonary valve stenosis
• Tricupsid insufficiency
• Pulmonary hypertension
• Many congenital cardiac abnormalities

Answer 12

Hypertrophy can be concentric or eccentric

Question 13

Hyperkalemia

Answer 13

Accumulation of extracellular K+ due to low ATP or low perfusion

Question 14

What are results of hyperkalemia?

Answer 14

• Depolarization of Resting potential
• Reduction in APA and Vmax
• Slow conduction velocity

Question 15

What are the ECG characteristics of hyperkalemia?

Answer 15

• Peaked T waves
• Widening of QRS complex
• MVA deviation usually to the left

Question 16

Why is the T wave peaked in cases of hyperkalemia?

Answer 16

• Hyperkalemia induces an increase in conductance of potassium channels, so there is faster repolarization.
• The T wave happens more quickly