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

Feeding mechanisms of animals, Feeding Mechanisms of Animals All anima...

Feeding Mechanisms of Animals All animals have evolved successful methods for extracting their required nutrition from the environment. Thus we find a diversity of feeding mec

Explain fossn ovalis defect ostium secundum defect, Explain Fossn Ovalis De...

Explain Fossn Ovalis Defect (Ostium Secundum Defect) ? This is the most common type of atrial septal defect. The usual approach is through a midline incision and median sterno

Introduction to biodiversity, Biological diversity is the new buzzword, the...

Biological diversity is the new buzzword, the magic door to international funding and global travelling. We share the earth with million of other living beings. Just as we humans m

How many asymmetric the amino acid serine have, How many asymmetric carbons...

How many asymmetric carbons does the amino acid serine have? Please explain with a strucutral diagram if possible.

Estrogens, Normal 0 false false false EN-IN X-NONE ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Explain fundamental of the photosynthesis process, Q. Is it correct to cons...

Q. Is it correct to consider water decomposition by the action of light the fundamental of the photosynthesis process? In addition ADP photophosphorylation, photic energy is al

Ground water, Ground Water Ground water represents a major subterranean...

Ground Water Ground water represents a major subterranean reservoir of fresh water. In general. it is not tapped by plants as it is too deep and does not suffer from loss due t

Explain an important strategy of group meetings, Explain An important strat...

Explain An important strategy of group meetings An important strategy could be to conduct small group meetings for behavioural change encouraging full participation. The group

Find the equilibrium molality of solute species, Find the equilibrium molal...

Find the equilibrium molality of solute species? Consider a hypothetical system in which two aqueous solutions are separated by a semipermeable membrane. Solution α is prepared

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