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 tympanum, What is the tympanum? In which part of the ear is it ...

What is the tympanum? In which part of the ear is it located and what is its function? The tympanum (or ear drum) is a membrane located in the middle ear just after the auditor

Find out the degrees of freedom, -The expected phenotypic ratio of offsprin...

-The expected phenotypic ratio of offspring. -The expected genotypic ratio of offspring. -Calculate the expected values you would use on a chi-square test (use genotypic rati

What do you mean by cori cycling, What do you mean by Cori Cycling? In ...

What do you mean by Cori Cycling? In this cycle, glucose released by peripheral tissues is metabolized to lactate, which is then resynthesized to glucose in the liver. This pro

What do you mean by primary visual and auditory cortex, Q. What do you mean...

Q. What do you mean by Primary Visual and Auditory Cortex? Primary Visual Cortex - in posterior aspects of occipital lobes.  Receives visual information from optic nerve (crani

Define deuterostomes in animal kingdom, Define Deuterostomes in animal king...

Define Deuterostomes in animal kingdom? Coelomate animals are thought to have separated into two divergent lines of evolution in terms of the way embryos develop. In the embryo

What is a biologic failure, What is A biologic Failure A biologic Fail...

What is A biologic Failure A biologic Failure can be defined as the inadequacy of the host to establish or to maintain osseointegration. The inability to establish osseoint

Explain about the anorexia nervosa, Explain about the Anorexia Nervosa? ...

Explain about the Anorexia Nervosa? Anorexia nervosa, as you have read above, is a psychological eating disorder characterized by somatic delusions that one is too fat despite

Classification of living things, Ask question what is classification of liv...

Ask question what is classification of livibg thingsMinimum 100 words accepted#

Phylum platyhelminthes, distinguishing characteristics of phylum platyhelmi...

distinguishing characteristics of phylum platyhelminthes?

Which type of gamete do the male respectively produce, Concerning the sex c...

Concerning the sex chromosomes of the XY system which type of gamete do the male and the female individuals respectively produce? The individual of the male sex is XY so he for

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