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

Crisis due to deforestation, Crisis due to Deforestation Due to conti...

Crisis due to Deforestation Due to continuing deforestation we are faced with a major ecological and socio-economic crisis. To reverse this trend of deforestation a National

Explain about probiotics and prebzotics, Explain about Probiotics and Prebz...

Explain about Probiotics and Prebzotics? We all have read or heard about probiotics and prebiotics at some point of time. However, what exactly do we mean by these terms? When

What is the objectives of evaluation of patient clinical, What is the OBJEC...

What is the OBJECTIVES of evaluation of patient clinical examination ? After going through this unit, you should be able to: 1. Carried out the general physics-examination; 2.

Define the effect of deficiency of vitamin c, Define the effect of Deficien...

Define the effect of Deficiency of Vitamin C? Severe ascorbic acid deficiency results in the development of the disease known as scurvy, three important manifestations of scur

Scheme of classification of phylum hemichordate, Q. Scheme of Classificatio...

Q. Scheme of Classification of phylum hemichordate? These are about 90 species of hemichordates. All are marine and live in the open sea or in muddy sediments. Hemichordata wer

How to use a key, Q. How to Use a Key? The use of a key is analogous to...

Q. How to Use a Key? The use of a key is analogous to travelling a high way, that forks repeatedly, each fork having roadside directions. If a traveller follows the proper dire

Define chromatography - basic separation technique, Define Chromatography -...

Define Chromatography - Basic Separation Technique? Chromatography is the most effective technique for the separation, purification and identification of one or more biological

Liquid manure handling, L iq uid manure handling This involves use of...

L iq uid manure handling This involves use of lot of water to flush the manure in to collection tank. Storage capacity depends on type of farm, irrigation facility, storage t

State the term - neuropsychologists, State the term - neuropsychologists ...

State the term - neuropsychologists Disorders of speech, language, reading, writing, and mathematical abilities are understood in terms of linguistics and the psychology of lan

What are the main structures within the cell nucleus, What are the main str...

What are the main structures within the cell nucleus? Within the cell nucleus the major structures are: the nucleolus, an optically dense region, spherical shaped, where there

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