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

Explain about thiol proteases, Explain about thiol proteases Group of  ...

Explain about thiol proteases Group of  thiol proteases, similar in structure to each other, are found in plants. These include  papain from the papaya fruit and  ficain from f

What are passive and active immunization, What are passive and active immun...

What are passive and active immunization? According to the duration of the protection how do these types of immunization differ? Active immunization is that in which an antigen

What is neurotransmitters , When the action potential reaches the nerve ter...

When the action potential reaches the nerve terminal it causes the let go of a chemical neurotransmitter by the synaptic vesicles. Mammalian nervous system employs many substances

Give detail explanation of aerobic exercises, Aerobic Exercises, Examples a...

Aerobic Exercises, Examples and their Do's and Don'ts In the aerobic exercises it requires activities performed for a longer period here we do like to mention certain activitie

Deficiency diseases-rickets, Rickets Rickets is a complex mineral defic...

Rickets Rickets is a complex mineral deficiency disease of young, growing animals. It is characterized by defective mineralization of growing bones, persistence of hypertrophic

Describe consciousness as the waking state, Q. Describe Consciousness as th...

Q. Describe Consciousness as the waking state? Consciousness as the waking state: consciousness is also referred to as the waking state as opposed for example to sleep. All

Reproductive cycle - human development, Reproductive Cycle The whole r...

Reproductive Cycle The whole reproductive cycle consists of an ovarian cycle and a uterine cycle. Figure illustrates one complete reproductive cycle. You can observe in the fi

What are the yeasts, Q. What are the Yeasts? Like mold, the term "yeast...

Q. What are the Yeasts? Like mold, the term "yeast" is commonly used but hard to define. As used here it refers to those fungi which are generally not filamentous but unicellul

Distinguish between epithelial and connective tissues, Distinguish between ...

Distinguish between epithelial and connective tissues with respect to their cell arrangement? PROVIDE a specific example (for both tissue types) of how the arrangement of cells hel

Define modes or techniques for chromatographic separation, Define Modes or ...

Define Modes or Techniques for Chromatographic Separation In practice, chromatographic separation may take one of these modes or techniques:   Paper chromatography (in w

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