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

Ribosomes, Ribosomes:     are minute nonmembranous  and dense spheroidal p...

Ribosomes:     are minute nonmembranous  and dense spheroidal particles or  granules. First observed by   electron   microscopy by palade 1955. Being only about 200 to 250 a in di

Autotomy and regeneration, Autotomy and Regeneration Shedding of body...

Autotomy and Regeneration Shedding of body parts in self-defense to avert the attention of the predator-enemy or in any other emergency is a type of autotomy (auto: self, tom

Common features of eye and limb development, Common Features of Eye and Lim...

Common Features of Eye and Limb Development A comparison of the embryonic development of the very much different organs, the eyes and the limb, points to various interesting

Explain what is genetic engineering, Explain brifly what is Genetic Enginee...

Explain brifly what is Genetic Engineering ? Genetic Engineering : Engineering techniques have been used in agriculture and horticulture for centuries. Certain plants or ani

What is etherification, What is Etherification The act or process of m...

What is Etherification The act or process of making ether; specifically, the process by which a large quantity of alcohol is transformed into ether by the agency of a small am

Botany, what is affinites of gymnosperm

what is affinites of gymnosperm

Explain about the smoking - methods of food processing, Explain about the S...

Explain about the Smoking - methods of food processing? Smoking was known as a method of food preservation at an early date. Foods are exposed to smokes by burning some special

Skeleton, what is the biological significance of skeleton

what is the biological significance of skeleton

What is linkage, What is linkage? Two genes are said to be under linkag...

What is linkage? Two genes are said to be under linkage, or linked, when they reside in the same chromosome. For instance, the research of the human genome discovered that t

Responding variable, what is the responding variable in catalyst to change ...

what is the responding variable in catalyst to change oil molecules

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