What are changes in st-segment, Biology

Assignment Help:

Q. What are changes in ST-Segment?

Normal Exercise Electrocardiogram ST and J Point

As the heart rate increases with exercise, a number of predictable changes occur in a normal ECG tracing. The PR-interval is shortened after 1 minute of exercise. The P-wave becomes taller and the Ta wave (wave of atrial repolarisation) increases, resulting in downward displacement of the PQ junction. This is particularly important because the so called baseline, for terms of evaluating ST-segment change, is below that usually considered to be isoelectric tracing. With exercise, the Ta wave tends to extend through the QRS and may influence that junction between the ST-segment and the T-wave.

Prognostic Significance

Asymptomatic patient-Abnormal test prevalence 5 to 12 per cent. Risk of event-9 times greater in abnormal test. 2 per cent event rate (angina) over 4 year follow up. BLS study - with risk factors- elderly patient - event rate varies 3.5 per cent to19 per cent in 9 years follow up. Females- 15 per cent to 20 per cent prevalence-less prognostic value.

Symptomatic Patient: Case Study

First stage positive: 5 per cent annual mortality, Low risk group: < 1 per cent annual mortality. It has become standard practice to use the line of PQ or PR junction as a marker for the baseline when the ST-segment is measured at one fourth the distance between the QRS and peak T in left to right leads, considerable depression is normally seen. The anterior posterior lead changes (V1 to V2) are less prominent than those in the lateral and vertical leads. The absence of significant ST-segment depression in young, vigorous boys and in athletic, middle aged men, suggests that the effect of the Ta wave, can usually be recognized because of the short duration (usually 0.045) of the J point depression.


Related Discussions:- What are changes in st-segment

What is the difference between taeniasis and cysticercosis, What is the dif...

What is the difference between taeniasis and cysticercosis? Taeniasis is the parasitic disease caused by the adult tapeworm installed within the human intestine. Cysticercos

What are autotrophic beings, What are autotrophic beings? What are heterotr...

What are autotrophic beings? What are heterotrophic beings? Autotrophic beings are those that can make their own food, i.e., that make organic material from inorganic compounds

Explain progressive loss of the axonal myelin sheath, What are some disease...

What are some diseases characterized by progressive loss of the axonal myelin sheath? Multiple sclerosis is a severe disease caused by progressive destruction of the myelin she

Ingestion of foreign bodies, Ingestion of Foreign Bodies: As we know  ...

Ingestion of Foreign Bodies: As we know  that small children are curious and  innocence children are notorious for inserting various object into their orifices like mouth, nos

What do you mean by st hystersis, Q. What do you mean by ST Hystersis? ...

Q. What do you mean by ST Hystersis? Ans. The rate of recovery of ST depression has been recognized as a measure of ischaemia severity for many years. When comparing the m

Show the process of synaptic transmission, Q. Fluoxetine is an antidepressa...

Q. Fluoxetine is an antidepressant drug that presents an action mechanism related to the synaptic transmission. What is that mechanism? Fluoxetine is a substance that inhibits

Discuss about sarcoplasmic reticulum, A healthy skeletal muscle fiber is is...

A healthy skeletal muscle fiber is isolated and has no external forces on it.  It has normal intracellular levels of ATP and is bathed in physiological saline.  Which of the follow

Define interferons - humoral mechanisms, Define Interferons - Humoral Mecha...

Define Interferons - Humoral Mechanisms Interferons are soluble proteins secreted naturally when cells become infected by foreign bodies. Infected lymphocytes release interfero

Define the functionality of cellulose, Functionality of cellulose Cellu...

Functionality of cellulose Cellulose has many uses as an anticaking agent, emulsifier, stabilizer, dispersing agent, thickener and gelling agent, but these are generally subsid

Crustaceans - hormones in growth and reproduction, Crustaceans - Hormones i...

Crustaceans - Hormones in Growth and Reproduction Arthropods have a tough and frequently hard exoskeleton made up of cuticle composed of chitin and protein. The cuticle impose

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd