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

Main factors for the growth of a population, Q. What are the main limiting ...

Q. What are the main limiting factors for the growth of a population? The factors that bound the growth of a population can be divided into abiotic factors and biotic factors.

Explain measles, Measles Adults born after 1956 who have not received ...

Measles Adults born after 1956 who have not received 2 doses of live measles vaccine (not the killed vaccine that was commonly used in the 1960s) after their first birthday an

What is the approximate ph of the salivary secretion, What is the approxima...

What is the approximate pH of the salivary secretion? Is it an acid or basic fluid? What are the main functions of saliva? The saliva pH is approximately 6.8. It is therefore a

What does genetics have to do with biology, What does genetics have to do w...

What does genetics have to do with biology? Genetics is the study of the genes found in genetic material (ex. DNA). DNA is found in the nucleus of your cells. The most signific

Aeromonas associated zoonotic disease, Aeromonas associated zoonotic diseas...

Aeromonas associated zoonotic disease Aeromonas causes gastrointestinal infections and extra intestinal infections such as cellulitis, wound infectiopn, peritonitis, endocardi

Do plants have tissue organization and specialized organs, Do plants have t...

Do plants have tissue organization and specialized organs? Plants have specialized organs (as reproductive organs, roots, limbs, leaves) and differentiated tissues (vascular t

Explain about the canning of food, Explain about the Canning of Food? Y...

Explain about the Canning of Food? You must have seen the markets flooded with canned products. Can you name a few of such products? Yes the canned juices, canned aerated drink

The statement is true or false, True or false, adaptations are the result o...

True or false, adaptations are the result of finding the best or only solution to a given problem a species faces.

Importance of biodiversity, T hese are some important uses of biodiversity....

T hese are some important uses of biodiversity. 1.   Source of food, medicines and drugs: (a)       Wheat, rice and maize are three carbohydrate rich crops and contribute

What would be the short- and long-term effects, In a possible future scenar...

In a possible future scenario, male fertility drops to zero, but, luckily, scientists develop a way for women to produce babies by virgin birth. Meiocytes are converted directly (w

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