Introduction to Left Ventricular Outflow Tract
Left ventricular outflow tract velocity time integral (LVOT VTI) is a useful means to calculate left ventricular stroke volume and diagnose syndrome of low cardiac output. This method is quite useful for finding out the optimal cut off value for inotrope administration in cases of acute heart failure (Ristow and et.al., 2011). Another such parameter happens to be Myocardial Performance Index (MPI) which is also a reliable measurement in order to evaluate left ventricular systolic and diastolic function in heart failure. Hence the requirement is to find out which best setting will produce a better LVOT VTI (Left Ventricular Outflow Track - Velocity Time Integral) and MPI (Myocardial Performance Index). There has thus been a preparation of research proposal for the same.
The proposal starts with description of aims, objectives as well as research question that has been formulated for given investigation. There is also a discussion about background study as well as sub sections in literature review to get a brief overview about the topic under study. Along with this, description of methods to be used as well as the rationale has been ensured. This is followed by proposing the timescale of study, ethical considerations as well as health and safety concerns.
Aims And Objectives
The given research study is based on the aim to identify the best setting that will produce a better Left Ventricular Outflow Track - Velocity Time Integral and Myocardial Performance Index.
Background And Literature Review
Sudden death because of cardiac failure is one of the major problems that are faced by most of the heart patients in the world. In this respect, congestive heart failure is one of the serious disorders of heart that either leads to a disability or death. It is the inability of heart to meet the needs of oxygen and tissues for oxygen and adequate nutrients. This leads to a decrease in cardiac output as the amount of blood that the heart pumps is also not adequate. The blood is not sufficient enough to circulate it to heart from lungs and body which causes shortness of breath and weakness. In this respect, it is quite important so as to measure and interpret the heart failure as well as severity (Hosenpud and Greenberg, 2007).
Echocardiography or echo test is a painless test that makes use of sound waves so as to create moving pictures of the heart. This uses standard two and three dimensional and Doppler ultrasound so as to create images of the heart. Electrocardiography has now become the standard means so as to evaluate the severity of aortic stenosis (AS) allowing for the confirmation of diagnosis, quantization of stenosis severity and its consequences and its analysis. It is a transthoracic interpretation and evaluation of electrical activity of the heart over a period of time (What Is Echocardiography? 2011). This is detected by electrodes that are attached to the surface of skin and then recorded by a devise that is placed outside the body. The technique is useful in measurement of electrical conduction system of heart. It picks up the electrical impulses that are generated by polarization and depolarization of cardiac tissues and then translates it into a waveform.
The translated waveform is then used to measure the rate and regularity of heartbeats, presence of any damage in the heart as well as size and position of chambers. Echo is also enabled to detect possible blood clots inside the heart, problems with the aorta and fluid buildup in the pericardium (Baumgartner, 2009). This also measure the effects of drugs or nay device like pace maker so as to regulate the heart. It also shows that how efficiently the chambers and valves of heart are working with respect to the flow of blood. The test of echocardiography is used in order to confirm a diagnosis or to determine the status of an existing problem in the heart as well as help in guiding a treatment (Conover, 2004).
Left ventricular outflow tract velocity time integral
A ventricular outflow tract is a portion of left ventricle in heart through which there is a passage of blood so that it can enter the great arteries. Left Ventricular Outflow Track (LVOT) connects to aorta and can be differentiated from rest of the ventricles. This outflow tract is derived from secondary heart field during process of cardio genesis (Mortensen and et.al. 2004). Left ventricular outflow tract velocity time integral (LVOT VTI) can be regarded as a simple method of Doppler echocardiography in order to measure the left ventricular stroke volume.
In the guidelines issued by European Society of Cardiology, LVOT VTI
Myocardial Performance Index
Congestive heart failure (CHF) is considered to be a major cause of mortality and disability. Patients suffering from a heart failure might have gone through a phase of asymptomatic (LV) left ventricular dysfunction where objective measurements of LV reveal an impairment of cardiac contractility but this does not reveal nay heart failure. There is still the lack of adequate value of different Doppler measurements and electrocardiograph in order to assess the heart failure (Shingu and et. al., 2010). Recently, it has been indicated that both LV systolic and diastolic functions are the predictors for subsequent heart failure. In this respect, the Doppler derived Myocardial Performance Index (MPI) also known as TEI-Doppler index is a fairly new index of combined systolic and diastolic function.
It refers to the sum of isovolumic contraction and relaxation time divided by the ejection time. MPI is considered to be a sensitive indictor for symptomatic heart failure in a cross sectional type of study (Karatzis and et. al., 2009). MPI has been demonstrated to be reproducible and reliable parameter in order to evaluate LV systolic and diastolic dysfunction in various kinds of heart disorders. In addition to this, MPI is also independent of arterial pressure, heart rate and preload. The technique is useful in the assessment of conditions where co existence of systolic and diastolic dysfunction exist such as patient in cardiac amyloisis, dilated cardiomyopathy, pulmonary hypertension along with right ventricular infarct and ventricular dysplasia. The technique also correlates closely with invasive measurements (Friedman and et. al., 2003). This is useful as this is an early indicator of left ventricular dysfunction in patients with normal systolic function and critical coronary artery disease.
Description Of Methods To Be Used Along With Rationale
The research strategy that has been used in present study happens to be qualitative and quantitative in nature. The qualitative strategy of research will assist in interpreting the relations that is present between Left Ventricular Outflow Track - Velocity Time Integral and Myocardial Performance Index so that a best setting can be produced. On the other hand, usage of quantitative research study will further aid in gaining an understanding about the processes by usage of statistical tools and techniques.
Research design can be regarded as an essential technique for any investigation that is undertaken on a research topic (Maxwell, 2011). The present study will make the use of exploratory design of research. It further aims at gaining of deep insights as well as getting familiar with investigatory phenomenon. It also assists in providing an answer to research question by undertaking a systematic investigation (Churchill and Lacobucci, 2009). This research design will further aid in finding out the best setting by study of literature hence it is the most suitable approach for this investigation.
Subject Selection and Description
The subjects to be selected for the present study happen to be patients who are suffering from heart failure of class third or fourth has been selected. The sample size chosen is 80 patients. This was a requirement so as to be aware about the best setting of Left Ventricular Outflow Track - Velocity Time Integral and Myocardial Performance Index in patients. Sampling involves for selection of subsets form entire population. In this respect, there has been a usage of purposive sampling technique. It is the one in which sample size is selected on basis of the knowledge of a population as well as purpose of study (Churchill and Lacobucci, 2009). The usage of this technique is quite apt as it would lead to selection of only those patients that have a specific characteristic in form of heart failure of type 3rd or 4th. The need of the researcher is to target a large number of patients within a short span of time without being much concerned about the proportionality. Hence usage of purposive sampling will be at for the study.
Ethical approval in order to conduct the research and study on patients will be taken from the appropriate NHS Research Ethics Committee which is a legal requirement. In order to achieve ethical approval from the patients under study some measures will be taken. Firstly, the participant will be given information regarding the rationale for conducting the study and what the study will result into. Prior to making a decision regarding participating in the research, participants will be given the freedom so as to ask any questions related to the study being conducted. They will be asked to sign a consent form which will indicate that they understand exactly what the research involves and they agree to participate in it (Suri, 2008). Along with this, participants will also inform that they are free to withdraw from the study any time they wish to.
Health And Safety / Coshh
All types of medical research studies have implication for health and safety. Hence, the requirement on part of any researcher is to identify any issues related cot health and safety. There is also a requirement to be increasingly aware about any hazards that the researcher may be exposed to while carrying out the study (Identifying risks to safety: Hazards to researchers Health & Safety, 2014). This involves for nursing safety of entire research team. The entire team is also required to be aware about Health and Safety implications of the proposed study.
- Advantages and disadvantages of observation. 2014.
- Ärnlöv, J. and et. al., 2004. Myocardial performance index, a Doppler-derived index of global left ventricular function, predicts congestive heart failure in elderly men.
- Baumgartner, H., 2009. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice.
- Chinen, D. and et. al., 2013. Left ventricular outflow tract velocity time integral correlates with low cardiac output syndrome in patients with acute decompensated heart failure. Eur Heart J. 34(1).