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 about aliphatic alcohols - non glyceride fractions, Define about Ali...

Define about Aliphatic alcohols - Non Glyceride Fractions? These are water-insoluble, with their content varying from 0.5-7% of the unsaponifiable matter. Rice bran oil contain

State the active hyperemia, Which of the following is true for active hyper...

Which of the following is true for active hyperemia, a local control mechanism within the circulatory system? A. There will be a decrease in force developed by smooth muscles s

Measurement of functional property of fats and oil, Measurement of Function...

Measurement of Functional Property of fats and oil Fats and oils have several functional properties that affect the quality of processed foods. In deep fat frying, the roles p

Natural and artificial ecosystem, Natural and Artificial Ecosystem i) N...

Natural and Artificial Ecosystem i) Natural ecosystems are those which are mostly free from human disturbances, such as tropical forests, grasslands, oceans, lakes and deserts.

fungi, Fungi The study of fungi (s. fungus) is called mycology. Fungi...

Fungi The study of fungi (s. fungus) is called mycology. Fungi are unicellular or multicellular chemoheterotrophic eukaryotes. They may be grouped into yeasts, molds and funga

What is class chondrichthyes, What is Class Chondrichthyes? Class Chond...

What is Class Chondrichthyes? Class Chondrichthyes takes its name from two Greek words. "Chondros"; means cartilage, and "ichthys"; refers to fish, therefore the name "cartilag

What is the determination of vitamin B2, What is the Determination of vitam...

What is the Determination of vitamin B 2 In the chemical method, the yellow-green fluorescence of aqueous solution of riboflavin is measured. In the microbiological assay, tur

Sulphur (s) - macronutrients, Sulphur (S) - Macronutrients Sulphur is ...

Sulphur (S) - Macronutrients Sulphur is present in the soil in inorganic and organic forms. In most soils organically bounds is the major S reservoir. The inorganic forms of S

Discuss resting membrane potential and nerve action potentia, Question 1 W...

Question 1 Which are the 3 different processes in the formation of urine? Explain Question 2 Discuss resting membrane potential and nerve action potential Question 3 Nam

What are the gynoecium and the androecium, Q. What are the gynoecium and th...

Q. What are the gynoecium and the androecium? What are the other structures of flowers? Androecium is set of male reproductive structures of flowers it comprehends the stamens

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