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

Define fluorides metabolism, Define fluorides Metabolism? Soluble fluor...

Define fluorides Metabolism? Soluble fluorides, even at high intake levels are almost completely absorbed from gastrointestinal tract. These include aqueous solutions of fluori

Stabilisation - climax, Stabilisation - Climax The whole process of s...

Stabilisation - Climax The whole process of succession results in stabilisation of the vegetation which is now in complete harmony with the environmental complex of that plac

What is the acrosome of the sperm cell, What is the acrosome of the sperm c...

What is the acrosome of the sperm cell? How is it formed? The acrosome is a structure that has a great number of digestive enzymes, it is located in the anterior end of the spe

Explain infectious proteins, Infectious proteins are present in: 1.Gemin...

Infectious proteins are present in: 1.Gemini viruses 2.Prions 3.Viroids 4.Satellite viruses Prions

How different are the heart chambers, Concerning the thickness of their wal...

Concerning the thickness of their walls how different are the heart chambers? The ventricle walls are thicker than the atrium walls as ventricles are structures responsible for

Hearing equilibrium, EQUILIBRIU M - Cristae and maculae are concerned ...

EQUILIBRIU M - Cristae and maculae are concerned with equilibrium. 1 .       DYNAMIC EQUILIBRIUM - Cristare detect turning or rotational movement of head ( angular ac

Explain about steatorrhoea, Q. Explain about Steatorrhoea? Steatorrhoea...

Q. Explain about Steatorrhoea? Steatorrhoea is a symptom of the disorders of fat metabolism and malabsorption syndrome and can be defined as n condition of foul-smelling bulky

Particulate theory - pre-mendelian theory, Particulate Theory (i)      ...

Particulate Theory (i)         Maupertuis (1689-1759) proposed that the body of each parent give rise to minute particles. (ii)         In sexual reproduction, these particl

Simple squamous epithelium - stratified squamous epithelium, Q. How differe...

Q. How different is the simple squamous epithelium from the stratified squamous epithelium? Where can these epithelia are found in the human body? The simple squamous epitheliu

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