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

Explain about fish epidermis, How different is the fish epidermis from the ...

How different is the fish epidermis from the amphibian epidermis? The fish epidermis is very thin and having mucus-secreting cells. The fish skin does not present keratin. The

Prevention of infection in icu unit, Prevention of Infection 1. Stri...

Prevention of Infection 1. Strict asepsis practiced in ICU.  2. All the invasive lines are covered with sterile-drape.  3. Antibiotics-broad-spectrum ones are adm

Define important points while working with autoclave, Define Important Poin...

Define Important Points While Working With Autoclave? Note: Following points should be kept in mind while working with autoclave. 1. Autoclave should not be packed tightly o

Explain about the nutrition security, Explain about the Nutrition Security?...

Explain about the Nutrition Security? Food security is a part of the broader concept of nutrition security. A household can be said to be nutritionally secure if it is able to

What are the cardiac muscles, What are the Cardiac muscles We know tha...

What are the Cardiac muscles We know that the heart muscles (cardiac muscles) are not under the control of  mind. The day we are born, it starts its activity and the day peopl

Define depolarization of the neuronal plasma membrane, Q. How is the depola...

Q. How is the depolarization of the neuronal plasma membrane generated? How does the cell return to its original rest? When the neuron receives a stimulus by the permeability o

Endosperm of gymnosperms and the endosperm of angiosperms, How dissimilar a...

How dissimilar are the endosperm of gymnosperms and the endosperm of angiosperms? In the gymnosperms the endosperm is haploid (n), it is called as primary endosperm. In the ang

Determine the categories of sleep disorders, Determine the categories of sl...

Determine the categories of sleep disorders Sleep disorders are generally divided into two major groups: 1) Narcolepsy, which is characterised by excessive sleep or brief in

Gene pool, Natural selection can therefore mean differential reproduction a...

Natural selection can therefore mean differential reproduction among members of the sarne gene pool. We earlier said that selection would promote those alleles that give rise to ph

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