The columns are:
age
sex: 1 = male, 0 = female
cp: chest pain type
1: typical angina
2: atypical angina
3: non-anginal pain
4: asymptomatic
trestbps: resting blood pressure
chol: serum cholestoral in mg/dl
fbs: fasting blood sugar 0 = >=120 mg/dl, 1 = <120 mg/dl
restecg: resting electrocardiographic results
0: normal
1: having ST-T wave abnormality
2: showing probable or definite left ventricular hypertrophy
thalach: maximum heart rate achieved
exang: exercise induced angina 0 = no, 1 = yes
oldpeak: oldpeak = ST depression induced by exercise relative to rest
slope: the slope of the peak exercise ST segment
1: upsloping
2: flat
3: downsloping
ca: number of major vessels (0-3) colored by flourosopy
thal: 0 = normal; 1 = fixed defect; 2 = reversable defect
target: 0 = less chance of heart attack 1 = more chance of heart attack