Heart Attack Prediction and Analysis
Krish Sharma, Dillon Goudie, Yashasvi Mantri, Avi Khorana
December 2021
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Question and Purpose
What causes heart attacks and which factors affect one’s chances of getting a
heart attack? Heart attacks can be incredibly devastating. According to the
CDC, one person dies every 36 seconds in the United States from heart attacks
and heart related diseases. Heart attacks usually occur because of poor lifestyle
choices. The question that needs to be answered is ”How do body conditions like
cholesterol, chest pain, age, etc. affect the chances of getting a heart attack?
” If this question can be answered, concerned individuals can try to make a
change before it is too late.
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Background Information on Heart Attacks
A heart attack occurs when an artery supplying the heart with blood and oxygen
becomes blocked. Fatty deposits build up over time, forming plaques in the
heart’s arteries. If a plaque ruptures, a blood clot can form and block the
arteries, causing a heart attack. Some signs that could indicate a heart attack
is chest pain, difficulties in breathing, and nausea.
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Approach to the Question
Figure 1 below shows a picture of the data set. The data set shows details like
the cholesterol, age, sex, resting blood pressure, and much more. I will use an
ANOVA (Analysis of variance) table and the coefficients to explain what body
conditions affect the chances of getting a heart attack. I got this data set from
Kaggle.com
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Figure 1
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Analysis and Evidence
Figure 2
The numbers below the variables (columns) in Figure 2 (age, cp, exng, etc.)
are the coefficients, or slopes, for the multiple linear regression model. These
coefficients are estimates of the independent impact each variable has on the
chances of getting a heart attack. caa is the variable that represents the major
vessels. The coefficient for caa is about -0.098. -0.098 is how much a chance of a
heart attack is expected to increase for each increment in the number of major
vessels. In simple terms, the chance of getting a heart attack decreases by 9.8%
for every extra major vessel. There are three major vessels, arteries, veins, and
capillaries. Arteries transport blood away from the heart. Veins return blood
back toward the heart. Capillaries surround body cells and tissues to deliver
and absorb oxygen, nutrients, and other substances. This also explains why
having more major vessels can decrease your chances of getting a heart attack.
The image below shows when the variable caa is graphed. Since x is the amount
of major vessels and y is the chances of a heart attack, we can see that the more
major vessels you have, the lower the chances.
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Figure 3
Something else that was noticed was that the higher the maximum heart
rate achieved is, the higher the chances of getting a heart attack is. In figure
2, thalacch stands for the maximum heart rate achieved. The number under
thallachh is about 0.003. The 0.003 shows how much the chances of a heart
attack is expected to increase for each increment of the maximum heart rate.
In other words, the chance of getting a heart attack increases by 0.3% for every
additional maximum heart rate. When the heart is beating too fast, it may not
pump enough blood to the rest of the body. Also this may result in difficulty in
breathing. This also explains why a higher heart rate can cause a heart attack.
The picture below is an ANOVA table. The ANOVA table explains the
importance of each body condition on the probability of a heart attack. The
R2 improve column shows the change that each variable makes in variability of
the linear regression model corresponding to predictability of the heart attack.
In the figure, the variable cp increases the R2 improve column where cp stands
for the type of chest pain. There are four different types of chest pains, typical
angina, atypical angina, non-anginal, and asymptomatic pain. Since cp has a
17% increase, it is a very important factor in determining the chances of a heart
attack. In figure 2, when the slope of cp is graphed, it is about 0.111. In figure
1, chest pain types are numbered 1,2,3, and 4 based on the severity for typical
angina, atypical angina, non-anginal, and asymptomatic pain respectively where
1 represents least severity. Every time the chest pain type changes from one type
to the other, the probability of heart attack changes by 11.1% accordingly. The
variables chol (cholesterol), restecg (resting electrocardiographic results), and
fbs (fasting blood sugar) seem to have barely any importance in the ANOVA
table.
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Figure 4
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Conclusion
In the end, it can be concluded that the three variables, caa (number of major
vessels), thalacch (the maximum heart rate achieved), and cp (type of chest
pain) play an important role in determining the probability of a heart attack.
A higher number of major body vessels ensures a lesser chance of heart attack.
Sometimes very high heart rates can result in higher probability of a heart
attack. The last thing that can be concluded is that chest pains of higher severity
can increase the chances of heart attack. These numbers are very important for
concerned individuals. It might help them in deciding whether to get checked
by the doctors or not. This way, people can get treated and aided before it
becomes too late, and the patient suffers a heart attack.
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