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 selenoproteins p and w, Define about Selenoproteins P and W? ...

Define about Selenoproteins P and W? The third group comprises of selenoprotein P, an extracellular constituent with multiple selenocysteine molecules. This has an antioxidant

Which responds to electrical signals, You have identified a protein in a ce...

You have identified a protein in a cell that you know that comes from the human body. With respect to that protein you have also determined that it allows sodium ions to go through

What is Non chordates?, what are the general characters of nonchordates, ex...

what are the general characters of nonchordates, explain

What is an advantage of using proteins, Plants use proteins, lipids and sta...

Plants use proteins, lipids and starch as seed storage compounds. What is an advantage of using proteins as a storage compound that are not afforded by lipids or starch?

Concept of production - ecosystems, Concept of Production - Ecosystems ...

Concept of Production - Ecosystems The ecosystems are unable to function, unless there is a constant input of energy from an external source that is sun. Solar energy enters t

Phlum arthropoda, how to write a project on phylum arthropoda

how to write a project on phylum arthropoda

Explain enzymes, Explain Enzymes Enzymes are the proteins that  act  ...

Explain Enzymes Enzymes are the proteins that  act  as  catalysts,  speeding the  rate  at which biochemical reactions proceed but not altering  the direction or nature of th

How genetic predisposition causing the underweight, How Genetic Predisposit...

How Genetic Predisposition causing the underweight? Mother's Health Status; Poor nutritional status of the girl child coupled with under nutrition during pregnancy results in L

Human skeleton, HUMAN SKELETON - Hard supportive or protective elements...

HUMAN SKELETON - Hard supportive or protective elements of the animal body form the skeleton system. It's study in osteology. EXOSKELETO N - Present outside skin. It

What is the difference between disaccharides, Q. What is the difference bet...

Q. What is the difference between disaccharides and monosaccharides? What are some examples of monosaccharides and of disaccharides that form them? Monosaccharides are simple m

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