Loading the available dataset

data(mtcars)
x  <- as.matrix(mtcars)
heatmap(x)


Enhanced heatmap in gplot

library(gplots)
## 
## Attaching package: 'gplots'
## The following object is masked from 'package:stats':
## 
##     lowess
heatmap.2(x, Colv=FALSE, dendrogram="row", 
          trace = 'none', 
          denscol = 'navy', 
          adjCol = c(1,2),# 2-element vector giving the (left-right, top-bottom) 
          #justification of row/column labels
          
          offsetRow = 1  #Number of character-width spaces to place between 
          #row/column labels and the edge of the plotting region.
          )

## change the direction of column lable
heatmap.2(x, srtRow=0, srtCol=90, 
          offsetRow=0, offsetCol=0, col=bluered)