Cardiac function problems

Question 1

What are the clinical symptoms of heart failure?

Answer 1

Fatigue
Orthopneoa

Paroxysmal nocturnal dysnoea

Question 2

What is seen on ECHO in HFpEF?

Answer 2

• Increased LV wall thickness
• LV cavity of normal size
• Left atrial elargement

LV EF: 70%

Question 3

What are the important clinical signs of HFpEF?

Answer 3

• BP (high can drive pathology)
• Increased JVP
• Peripheral oedema
• Pulmonary crackles
• LV hypertrophy
• LA enlargement
• EF: 70%

Question 4

Whats the ejection fractions of HF?

Answer 4

HFrEF: <40%
HFpEF: >50%

Question 5

Whats the likely mechanisms of HFpEF?

Answer 5

Relaxation:
- X-bridge detachment, Ca removal
- Requires ATP
- Elastic recoil

Compliance
- Titan (P/ph status i.e PKA reduces stiffness)

Collagen deposition
- Increased stiffness?

VIP: Diastole is a function of myocytes and ECM therefore if these features change it can impair relaxation…

Question 6

What determines LV diastolic function?

Answer 6

Active and passive processes at levels of:
- Myocytes
- ECM
- LV chamber
- Forces extrinsic to the myocardium i.e preload, afterload etc

Question 7

What determine myocyte relaxation?

Answer 7

• Tension is released when Ca dissociates from Tn C
• Ca decline results in reduced Ca-Tn C binding, Ca decline due to NCX and SERCA
• ATP dependent
• Titan recoil from compression
• Cardiac afterload affects rate of relaxation

Question 8

Look at slide 21

Answer 8

Now please

Question 9

Why doe HFpEF patients get pulmonary oedema?

Answer 9

Back pressure onto lungs

Question 10

Why do HFpEF patients get worse shortness of breath at night?

Answer 10

Increased thoracic blood volume when lying thus more fluid on the longs etc

Talk about hydrostatic pressure when standing, oedema etc.

Sitting upright reduces venous return to the heart.

Question 11

What indicates left bundle branch block?

Answer 11

M shaped or notched QRS in LV leads

• 1, aVL, V4, V5

Question 12

What can inflammation/fibrosis in myocardium conduction system of HFpEF lead to?

Answer 12

• # Dis-coordinated conduction
• Dyssynchronous contraction and relaxation
• Systolic impairment and reduced LV filling time

Poor contraction and relaxation

Question 13

How can LBBB affect mechanical function?

Answer 13

• LV systole prolonged
• RV/LV valve sequence changes
• Slow LV relaxation
• LV filling time shortened

Question 14

What is CRT?

Answer 14

Cardiac resynchronizing therapy

• Pacing device to coordinated contration
  = No extre energy / O2 demand (unlike dobutamine), may even lower energy / oxygen demand

Question 15

What are the risks of CRT?

Answer 15

Surgical risks etc

Question 16

What are the benefits of CRT in a HFpEF patient with LBBB?

Answer 16

• Improved cardiac efficiency, reverse remodelling, alleviation of HF symptoms, improved quality of life, reduced morbidity/ hospitalisations, improved survival.