'BIOLOGICAL PACEMAKER' TESTED IN LABBy Helen Briggs

Health editor, BBC News website17 July 2014

Friday 1 August 14

Grow-your-own pacemakers are a step closer to reality, after pioneering experiments in pigs.

Conventional pacemakers are electronic devices that are implanted into the chest to control an abnormal heartbeat. The pacemaker sends regular electrical pulses to keep the heart beating regularly.

Pacemakers had been around since the early 1960s, and while technology was constantly improving, researchers were looking ahead to a day when perhaps an implantable device might not be needed for some patients, said senior cardiac nurse Amy Thompson.

Scientists are working on creating biological pacemakers that might one day be used in their place, either as a temporary or more permanent measure.

Friday 1 August 14

Scientists turned heart cells into pacemaker cells by injecting a gene.

The researchers injected a gene into pigs with a heart condition that causes a very slow heart rate.

The gene therapy converted some of the billions of ordinary heart muscle cells into much rarer specialised cells that kept the heart beating in rhythm.

The patch of cells the size of a peppercorn had acted as a pacemaker for two weeks, taking over the function of a conventional pacemaker, said the US team.

Friday 1 August 14

Biological pacemaker cells

It is possible that one day, we might be able to save lives by replacing hardware with an injection of genes

Friday 1 August 14

What Leonardo taught us about the heart

Who was Leonardo da Vinci?

Leonardo da Vinci was born in Tuscany, Italy, in 1452 - the illegitimate son of a farmer's daughter. He is known as one of the greatest artists who ever lived. His most famous works of art are ‘The Last Supper’ and ‘the Mona Lisa’.

By Philippa Roxby, Health reporter, BBC News website, 28 June 2014

Friday 1 August 14

Heart

The heart is the body's engine room, responsible for pumping life-sustaining blood via a 60,000-mile-long (97,000-kilometer-long) network of vessels. The organ works ceaselessly, beating 100,000 times a day, 40 million times a year—in total clocking up three billion heartbeats over an average lifetime. It keeps the body freshly supplied with oxygen and nutrients, while clearing away harmful waste matter.

http://science.nationalgeographic.com/science/health-and-human-body/human-body/heart-article/

Friday 1 August 14

Anatomy of the heart

Chambers of heart

Circulation route

http://searchwarp.com/swa469270-Anatomy-For-Beginners-Part-2-Getting-Pumped-Ladies-And-Gentlemen-I-Give-You-The.htm

http://medicalnights.com/simple-diagram-of-human-heart/

Friday 1 August 14

Heart-Lung Link

Blood purification

http://boralginmages.appspot.com/?page=circulatory-system-diagram-for-kids

Friday 1 August 14

Where is the pacemaker in the heart ?

Implanted pacemaker

http://news.nationalgeographic.com/news/2010/09/100914-fuel-cell-biofuels-medical-implants-human-health/

Friday 1 August 14

Biological Pacemaker

Pacemaker circuit

www.pennmedicine.org, v1.medic-ce.com, thepad.pm

Friday 1 August 14

Pacing the heart through pacemaker circuit

Source of ECG

Friday 1 August 14

Conducting system & Contractile System

Why there are two systems?

Friday 1 August 14

Little bit about anatomy of the heart

Layers of myocardium

Friday 1 August 14

Conduction system

Friday 1 August 14

Timing for the spread of the electrical impulse

The impulse is transmitted through the entire Purkinje fiber system within 30 msec, ensuring that a rhythmic and concerted ejection of blood from the ventricles take place as the endocardial cells and finally the epicardial cells are stimulated.

Friday 1 August 14

Linking conducting & contracting systems

Friday 1 August 14

Conducting system set the contracting system in action

1. AP ofPacemaker ?

2. AP ofC-Myocyte ?

Friday 1 August 14

Overall electrical activity of the heart: EKG/ECG

After conduction begins at the sinoatrial (SA) node, cells in the atria begin to depolarize. This creates an electrical wavefront that moves down toward the ventricles, with polarized cells at the front, followed by depolarized cells behind. The separation of charge results in a dipole across the heart (the large black arrow shows its direction). Modified from D.E. Mohrman and L.J. Heller (eds.), Cardiovascular Physiology, 5th Ed., 2003. Reproduced with permission of theMcGraw-Hill Companies.The dipole causes current flow in the surrounding body fluid between the ends of the heart, resulting in a fluctuating electric field throughout the body.

Friday 1 August 14

Willem Einthoven (a Dutch physiologist; 1860-1927) made the first ECG recording in 1895

String galvanometer

http://www.metealpaslan.com/ecg/linken1.htm

Friday 1 August 14

The Nobel Prize in Physiology or Medicine 1924

was awarded to Willem Einthoven "for his discovery of the mechanism of the electrocardiogram".

Friday 1 August 14

Part of the nobel lecture

Einthoven's name is linked partly with the design of a physical instrument, the string galvanometer, partly with the so-called electrocardiogram, a record of the electrical potential fluctuations at the surface of the body, which accompany the heart beat. The heart beat, like the piston movement of a steam engine, is a cyclic process. Behind this process lies, in the first place, a similarly cyclic process in the heart muscle.

What we essentially measure in ECG or EKG ?

Using electrodes on the surface of the skin we detect the voltage of the electrical field. This is what provided in the electrocardiogram (ECG) or EKG

Friday 1 August 14

ECG pattern

P, Q, R, S, T waves are also first defined by Willem Einthoven in 1895.

Friday 1 August 14

EKG & physiological states of the body

Friday 1 August 14

Characteristics of different waves

P Wave: Depolarization of the atria

PR Interval: Time from the onset of atrial depolarization (P wave) to onset of ventricular depolarization (QRS complex

Duration of atrioventricular conduction: [120 to 200 m sec]

QRS Complex: Duration of depolarization of the ventricles [<120 m sec]

QT Interval: Depolarization and repolarization of the ventricles, [<420 m sec; potentially <440 in women m sec]

RR Interval: Duration of ventricular cardiac cycle (an indication of ventricular rate)

Friday 1 August 14

What ECG tells......

‘Yes’ and ‘No’

1. Anatomical orientation of the heart2. Relative size of the heart chambers3. Heart rate4. Rhythm5. Origin of excitation6. Spread of the impulse7. Decay of excitation8. Disturbances of the above events (not the cause)

Electrocardiogram (ECG or EKG)The ECG gives “NO” direct information about the contraction and pumping efficiency of the heart.

Friday 1 August 14