TeachableMedicalNews article 11252020

Teachable moment in classrooms:

  1. cellular basis of life chapter – protein synthesis in cells can be changed by stimulus
  2. muscle tissue chapter – thick and thin filaments in the sliding filament muscle contraction model
  3. muscle tissue chapter – the role of calcium in muscle contraction model
  4. heart chapter – relationship of stroke volume to cardiac output

The news item:  Recently a new electronic device, Optimizer Smart, was in the news:

https://www.cnbc.com/2019/03/25/fda-approves-new-device-for-patients-with-chronic-heart-failure.html

The article states that this device is not a pacemaker; it sends non-excitatory signals, and this way it improves the squeezing ability of the heart which, in turn, improves the physical abilities of the heart failure patients.

So, Why Do I Care??  In the USA there are about 5 million people living with congestive heart failure. There are over 500,000 new cases every year, and 280,000 deaths. The people who live with congestive heart failure have a diminished quality of life because their physical activities are limited. Any new approach to help those patients is welcome news.

Plain English, Please!!!  First, let’s talk about what heart failure is. Contrary to popular belief “heart failure” doesn’t mean that the heart stops beating. Heart failure means that the cardiac output (the blood volume pumped out each minute) drops to 66% of the normal, and the heart fails to supply enough blood to our organs. Malfunction of just one of the parts of the heart (valves, pacemaker structures, cardiac muscle) is enough to cause heart failure. The cardiac output is calculated by taking the blood volume pumped with each heart beat (stroke volume) and multiplying it with the heart rate.

Second, let’s talk about what “squeezing ability” means. The “squeezing ability” is the force of the hear that pushes the blood from the ventricles with each heartbeat, and so, this is the stroke volume part of the cardiac output. That squeezing ability comes from the contraction of cardiac muscle cells when inside those cells the contraction engines (thick filaments pulling on the thin filaments) are turned on and the action of the engines shortens the cells. Millions of these engines are present in each muscle cell. For each heart beat the engines have to be turned on anew. The finger that flicks the contraction engine switch on is the calcium ion.

Third, let’s talk about what the Optimizer Smart device actually does. In the heart muscle cells of a congestive heart failure patient many engines are sitting quiet, because there is not enough calcium to switch on all those engines.  That is because in heart failure the cells don’t have enough proteins that allow calcium to flow into the cells. The contractions of those muscle cells are weak, the heart squeezes out less blood, and the body receives less oxygen and nutrition.  The Optimizer Smart device send low level electrical impulses to the heart muscle cells, and the cells respond by making more protein that allows calcium to flow into the cells. With more calcium in the muscle cells more engines will be turned on which create a bigger force, the heart will squeeze more blood, and the oxygen and nutrient delivery will improve in the patient.