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

Transmembrane voltage, How come that difference of K+ and Na+, which are bo...

How come that difference of K+ and Na+, which are both monovalent cations, creates the difference of the net charge of the membrane at different sides?

Illustrates the effect of wall movement on earth pressure, Illustrates abou...

Illustrates about the effect of wall movement on earth pressure? Effect of wall movement on earth pressure About fifty years ago Terzaghi conducted a series of tests on larg

Define vaccine immunogenicity, Immunogenicity Based on immunogenicity s...

Immunogenicity Based on immunogenicity studies and experience with other vaccines, the new meningococcal conjugate vaccine (Menactra) should be highly effective in preventing m

Determine some food sources of chromium, Determine some Food Sources of chr...

Determine some Food Sources of chromium? Chromium occurs in trivalent form in foods. Good sources of chromium include whole grains, spices and condiments, meats especially orga

What would the volume for reaction, The component is DNA. The stock concent...

The component is DNA. The stock concentration is 10mg/ml and the final concentration/amount is 25ug. What is the volume for 1 reaction? For 5 reactions?

Waxes, WAXES These are monoglyceride compounds. They are chemical...

WAXES These are monoglyceride compounds. They are chemically inert (due to absence of double bonds) and insoluble in water. On heating they become soft and pliable

Are mollusc metameric beings, Q Are mollusc metameric beings? Exclusively a...

Q Are mollusc metameric beings? Exclusively analyzing this feature could it be said that molluscs are evolutionarily proximal to nematodes or to annelids? In molluscs there is

Effects on ecosystem - air pollutants, Effects on Ecosystem - Air pollutant...

Effects on Ecosystem - Air pollutants The effects of pollutants on ecosystem become visible after a long period of exposure. In highly industrialised countries the vegetation

What is a single cell protein, What is a single cell protein? The prote...

What is a single cell protein? The proteins obtained from microbial sources, i.e. algae, fungi, bacteria, yeast etc. are referred to as Single Cell Proteins. These are isolated

Permanent wilting percentage (pwp), Permanent Wilting Percentage (PWP) ...

Permanent Wilting Percentage (PWP) It is the percentage of moisture in the soil at which a plant wilts and does not recover unless water is added to the soil. PWP for clay is

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