EKG (Electrocardiography) Heart Test

Electrocardiograph- is a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded by a device external to the body. 

• The recording produced by this noninvasive procedure is termed an electrocardiogram.

 The EKG device detects and amplifies the tiny electrical changes on the skin that are caused when the heart muscle depolarizes during each heartbeat.

• At rest, each heart muscle cell has a negative charge, called the membrane potential, across its cell membrane. Decreasing this negative charge towards zero, via the influx of the positive cations is called depolarization, which activates the mechanisms in the cell that cause it to contract.

• During each heartbeat, a healthy heart will have an orderly progression of a wave of depolarization that is triggered by the cells in the sinoatrial node, spreads out through the atrium, passes through the atrioventricular node and then spreads all over the ventricles. 
• This is detected as tiny rises and falls in the voltage between two electrodes placed either side of the heart which is displayed as a wavy line either on a screen or on paper. This display indicates the overall rhythm of the heart and weaknesses in different parts of the heart muscle.
•  Sinoatrial Node-A small body of specialized muscle tissue in the wall of the right atrium of the heart that acts as a pacemaker by producing a contractile signal at regular intervals
•  Atrioventricular Node-a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle

•  Usually, more than two electrodes are used, and they can be combined into a number of pairs 

• For example: left arm (LA), right arm (RA) and left leg (LL) electrodes form the three pairs LA+RA, LA+LL, and RA+LL
• The output from each pair is known as a lead. Each lead looks at the heart from a different angle. Different types of ECGs can be referred to by the number of leads that are recorded

Placement of Electrodes:Ten electrodes are used for a 12-lead ECG. The electrodes usually consist of a conducting gel, embedded in the middle of a self-adhesive pad onto which cables clip. Sometimes the gel also forms the adhesive.^[13] They are labeled and placed on the patient's body as follows

• Electrode label (in the USA)	Electrode placement
  RA	On the right arm, avoiding thick muscle.
  LA	In the same location where RA was placed, but on the left arm.
  RL	On the right leg, lateral calf muscle.
  LL	In the same location where RL was placed, but on the left leg.
  V1	In the fourth intercostal space (between ribs 4 and 5) just to the right of the sternum (breastbone).
  V2	In the fourth intercostal space (between ribs 4 and 5) just to the left of the sternum.
  V3	Between leads V2 and V4.
  V4	In the fifth intercostal space (between ribs 5 and 6) in the mid-clavicular line.
  V5	Horizontally even with V4, in the left anterior axillary line.
  V6	Horizontally even with V4 and V5 in the midaxillary line.

Echo(Echocardiography) Heart Test

The Echocardiography Heart Test otherwise known as Echo for short is a sonogram of the heart. It  uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart

•  A Doppler Ultrasound test uses reflected sound waves to see how blood flows through a blood vessel. It helps doctors evaluate blood flow through major arteries and veins, such as those of the arms, legs, and neck. It can show blocked or reduced blood flow through narrowing in the major arteries of the neck that could cause a stroke. It also can reveal blood clots in leg veins (deep vein thrombosis, or DVT) that could break loose and block blood flow to the lungs.

 

 An Echo can provide a wealth of helpful information, including the size and shape of the heart, pumping capacity, and the location and extent of any tissue damage. An Echo can also give physicians other estimates of heart function such as a calculation of the cardiac output, ejection fraction, and diastolic function (how well the heart relaxes). It can also produce an  accurate assessment of the blood flowing through the heart, using pulsed or continuous waves. This allows assessment of both normal and abnormal blood flow through the heart.

•  Color Doppler as well as spectral Doppler is used to visualize any abnormal communications between the left and right side of the heart, any leaking of blood through the valves, and to estimate how well the valves open (or do not open in the case of valvular stenosis).
•  Valvular Stenosis- an abnormal narrowing in a blood vessel or other tubular organ or structure.

The use of Stress Echo also helps doctors to determine whether any chest pain or associated symptoms are related to heart disease. But its biggest advantage is that it is noninvasive (doesn't involve breaking the skin or entering body cavities) and has no known risks or side effects.

•  Transthoracic Echocardiogram-A standard echocardiogram
•  Stress Echocardiography-A stress echocardiogram, also known as a stress echo or SE, utilizes ultrasound imaging of the heart to assess the wall motion in response to physical stress
•  Three-Dimensional Echocardiography-3D echocardiography (also known as 4D echocardiography when the picture is moving) is now possible, using a matrix array ultrasound probe and an appropriate processing system. This enables detailed anatomical assessment of cardiac pathology, particularly valvular defects, and cardiomyopathies.

•  Contrast echocardiography-Contrast echocardiography, or Contrast-enhanced ultrasound is the addition of ultrasound contrast medium, or imaging agent, to traditional ultrasonography. The ultrasound contrast is made up of tiny microbubbles filled with a gas core and protein shell. This allows the microbubbles to circulate through the cardiovascular system and return the ultrasound waves creating a highly reflective image.

The Virtual Neurophysiology Lab

Below is the steps to doing the Virtual Neurophysiology Lab to do the lab your self follow the link. http://www.hhmi.org/biointeractive/vlabs/neurophysiology/index2startlab.html
 
Purpose

1. To understand how to measure electrical impulses and observe the structure of neurons in a model organism such as the leech

Materials

1. Leech tongs
2. 20% ethanol solution
3. Leech Container w/Leech
4. Dissection Tray
5. Scissors
6. Pins
7. Forcepts
8. Probe
9. Microscope
10. 
    

Procedure

1. Catch and anesthetize the leech in 20% ethanol solution
1. Ethanol is not an anesthetic for vertebrate animals, but can be an effective anesthesia for small creatures that breathe through the skin like the leech. 
2. Like in many things, too high a concentration will be harmful or fatal
2. Pin the animal dorsal side up through the anterior and posterior suckers onto a dissection tray, stretching the animal in the process
3. Using scissors, make a cut in the skin along the mid-line on the dorsal surface, taking care not to damage deep structures.
4. Using forceps, carefully tease apart the skin along the cut and pin down the left and right halves of the skin to each side, so that the leech is pinned open with the inside of the skin facing up. 
1. This exposes the innards of the leech, including the digestive, excretory and reproductive organs. You cannot see the nervous system yet, because they are located ventrally.
5. Carefully remove the guts and other internal structures to expose the ventrally located nerve cord. 
1. The nervous system of the leech is encased within the ventral sinus, which is dark green in color. 
6. Notice that there are many swellings up and down the sinus. These contain the segmental ganglia of the nervous system. 
1. To make one of them accessible, first we cut a window in the body wall underneath a ganglion, taking care not to damage the nerve cord or any attached nerves in the process.
7.  Isolate a section of the animal by making 2 parallel cuts across the animal (perpendicular to the anterior-posterior axis), but sufficiently separated so that the strip you remove contains at least one ganglion. 
8. Then, with forceps, flip the piece of skin over so that the outer skin is now face up. Pin the skin down. If you don't know why you are doing this, go read the Why are we doing this? of Step 5 and come back. 
9. Cut the sinus with an ultra fine scalpel and using fine forceps, carefully tease apart the sinus to expose the ganglion. 
1. Individual cells can now be viewed under the microscope.
10. Click on the electrode to gain control of it. 
11. Move the electrode to somewhere over the ganglion then click on the mouse button. 
1. This simulates the process of penetrating the cell
2.  Keep your eyes glued to the oscilloscope display while you are doing this. 
3. If you find a cell, the display will change. 
4. If you see no change, then you have not found a cell. 
5. Keep moving your electrode around and clicking until you find a cell.
12. Using a feather, probe or forceps, push around the skin of the animal. 
1. Observe if the cell you have penetrated responds to weak (feather), medium (probe), strong (forceps) or any stimulus.
2. Note the pattern of response. 
3. The cell may fire action potentials or spikes. 
4. The response characteristics will be used when you are comparing your data with published data compiled in the atlas.
13. When you are satisfied with the electrophysiology, you can start the anatomical investigation by injecting the cell with a fluorescent dye. 
1. Push the button labeled "Dye Injection." 
14. Having pushed the button labeled "Dye Injection," the amplifier system has passed an electric current from the electrode that resulted in the ejection of Lucifer Yellow from the tip of the electrode into the intracellular space.
    
    1. Lucifer Yellow will passively spread throughout the cell after a while. Now you can turn on ultraviolet (UV) light by pushing "UV Switch.". Lucifer Yellow fluoresces bright yellow-green under UV and you will be able to visualize the cell in question, including its axon, dendrites, cell body and so on. 
    2.  You now have electrophysiological data and neuroanatomical data from your experiment. Try to identify the cell based on published data (Atlas) There are many cells in different locations of this ganglion. Repeat the whole procedure for as many cells as you would like. 

Open Heart Surgery

Open Heart Surgery- is any surgery where the chest is opened and surgery is done on the heart muscle, valves, arteries, or other parts of the heart

History:

1. The earliest known operation done on the b pericardium (the sac that surrounds the heart) took place in the 19th century and was performed by Francisco Romero,Dominique Jean Larrey, Henry Dalton, and Daniel Hale Williams.
2. The first surgery on the heart itself was performed in Norway by a Norwegian Surgeon by the name of Axel Cappelen
1.  Took place on September 4, 1895
2. Unfortunately  died from what the post mortum proved to be Mediastinitis on the third postoperative day.
1. Mediastinitis- is swelling and irritation (inflammation) of the area between the lungs. This area contains the heart, large blood vessels, windpipe (trachea), esophagus, thymus gland, lymph nodes, and connective tissues
3.  Then a heart surgery done by Dr. Ludwig Rehn of Frankfurt, Germany. Who repaired a stab wound to the right ventricle on September 7, 1896
1. This was the first successful heart surgery
4.  The first successful intracardiac correction of a congenital heart defect using hypothermia was performed by Dr. C. Walton Lillehei and Dr. F. John Lewis at the University of Minnesota on September 2, 1952. 
5. The following year, Soviet surgeon Aleksandr Aleksandrovich Vishnevskiy conducted the first cardiac surgery under local anesthesia.

How it's Done: 

A heart-lung machine is usually used during open heart surgery. While the surgeon works on the heart, the machine helps send oxygen-rich blood to the brain and other organs.(Procedure used from: http://www.nlm.nih.gov/medlineplus/ency/article/002950.htm)

1. Your heart surgeon will make a 2-inch to 5-inch-long surgical cut in the chest wall. Muscles in the area will be divided so your surgeon can reach the heart. The surgeon can fix or replace a valve or perform bypass surgery.
2. During endoscopic surgery, your surgeon makes one to four small holes in your chest. Then your surgeon uses special instruments and a camera to perform the surgery.
3. During robot-assisted valve surgery, the surgeon makes two to four tiny cuts (about 1/2 inch to 3/4 inch) in your chest. The surgeon uses a special computer to control robotic arms during the surgery. The surgeon sees a three-dimensional view of the surgery on the computer. This method is very precise.
4. You will not need to be on a heart-lung machine for these types of surgery. However, your heart rate will be slowed with medicine or a mechanical device. If there is a problem with these procedures, the surgeon may have to open the chest to do the surgery.

Risks and Complications: Like any surgery Open Heart Surgery has its risks and Complications. Down below is a list of the risks in heart surgery as well as possible complications that have been reported and that you have the possibly of getting.

1. Bleeding: May occur at the incision site or from the area of the heart where surgery is performed
2. Abnormal heart rhythm: In rare cases a temporary external, or permanent internal pacemaker may be necessary to correct this problem.
3. Ischemic heart damage: Damage to heart tissue caused by a lack of blood flow to the heart
4. Death: The risk of death is increased in surgeries where the heart is stopped for the procedure.
5. Blood clots: Clots may form in and around the heart or travel through the bloodstream.
6. Stroke: Often caused by clots that form in the blood after surgery
7. Blood Loss: In some cases, a transfusion may be necessary.
8. Emergency surgery: If a problem is discovered after surgery, an emergency surgery may be necessary to repair any problems.

Recovery

1. Keep your incision(s) clean and dry.
2. Use only soap and water to cleanse the area.
3. Do not apply ointments, oils, salves or dressings to your incision unless specifically told to do so.
4. Eat a healthy diet to help healing. 
5. Bathing
1.  If your incision is healing and dry, quick showers (no longer than 10 minutes) are usually allowed. If you have sutures in your chest, stand with your back to the shower spray.
6.  To cleanse the incision site:
1. Use regular soap, not perfumed soap or body wash. Don’t try a new brand of soap during your recovery.
2. Place soapy water on your hand or washcloth and gently wash the incision(s) up and down. Do not rub the incision(s) with a washcloth until the scabs are gone and the skin is completely healed.
7.  Call your doctor if signs of infection appear: 
1.  
2. Increased drainage or oozing from incision
3. Increased opening of the incision line
4. Redness or warmth around the incision
5. Increased opening of the incision line
6. Increased body temperature (greater than 101 degrees Fahrenheit or 38 degrees Celsius)
7. If you have diabetes and your blood sugar levels begin to vary more than usual