diff --git a/IPython/frontend/html/notebook/kernelmanager.py b/IPython/frontend/html/notebook/kernelmanager.py
index 60ef907..1306b77 100644
--- a/IPython/frontend/html/notebook/kernelmanager.py
+++ b/IPython/frontend/html/notebook/kernelmanager.py
@@ -20,7 +20,7 @@ from tornado import web
 
 from IPython.kernel.multikernelmanager import MultiKernelManager
 from IPython.utils.traitlets import (
-    Dict, List, Unicode, Float, Integer,
+    Dict, List, Unicode, Integer,
 )
 
 #-----------------------------------------------------------------------------
@@ -33,9 +33,6 @@ class MappingKernelManager(MultiKernelManager):
 
     kernel_argv = List(Unicode)
     
-    time_to_dead = Float(3.0, config=True, help="""Kernel heartbeat interval in seconds.""")
-    first_beat = Float(5.0, config=True, help="Delay (in seconds) before sending first heartbeat.")
-    
     max_msg_size = Integer(65536, config=True, help="""
         The max raw message size accepted from the browser
         over a WebSocket connection.