--- a
+++ b/python/mit_db.py
@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+
+"""
+mit_db.py
+
+Description:
+Contains the classes for store the MITBIH database and some utils
+
+VARPA, University of Coruna
+Mondejar Guerra, Victor M.
+24 Oct 2017
+"""
+
+import matplotlib.pyplot as plt
+import numpy as np
+
+# Show a 2D plot with the data in beat
+def display_signal(beat):
+    plt.plot(beat)
+    plt.ylabel('Signal')
+    plt.show()
+
+# Class for RR intervals features
+class RR_intervals:
+    def __init__(self):
+        # Instance atributes
+        self.pre_R = np.array([])
+        self.post_R = np.array([])
+        self.local_R = np.array([])
+        self.global_R = np.array([])
+        
+class mit_db:
+    def __init__(self):
+        # Instance atributes
+        self.filename = []
+        self.raw_signal = []
+        self.beat = np.empty([]) # record, beat, lead
+        self.class_ID = []   
+        self.valid_R = []       
+        self.R_pos = []
+        self.orig_R_pos = []