diff --git a/host/integration_test.go b/host/integration_test.go
index eea54d89172..a7881d94007 100644
--- a/host/integration_test.go
+++ b/host/integration_test.go
@@ -1360,6 +1360,183 @@ func (s *integrationSuite) TestActivityTimeouts() {
 	s.True(workflowComplete)
 }
 
+func (s *integrationSuite) TestActivityHeartbeatTimeouts() {
+	id := "integration-activity-heartbeat-timeout-test"
+	wt := "integration-activity-heartbeat-timeout-test-type"
+	tl := "integration-activity-heartbeat-timeout-test-tasklist"
+	identity := "worker1"
+	activityName := "timeout_activity"
+
+	workflowType := &workflow.WorkflowType{}
+	workflowType.Name = common.StringPtr(wt)
+
+	taskList := &workflow.TaskList{}
+	taskList.Name = common.StringPtr(tl)
+
+	request := &workflow.StartWorkflowExecutionRequest{
+		RequestId:    common.StringPtr(uuid.New()),
+		Domain:       common.StringPtr(s.domainName),
+		WorkflowId:   common.StringPtr(id),
+		WorkflowType: workflowType,
+		TaskList:     taskList,
+		Input:        nil,
+		ExecutionStartToCloseTimeoutSeconds: common.Int32Ptr(300),
+		TaskStartToCloseTimeoutSeconds:      common.Int32Ptr(2),
+		Identity:                            common.StringPtr(identity),
+	}
+
+	we, err0 := s.engine.StartWorkflowExecution(createContext(), request)
+	s.Nil(err0)
+
+	s.logger.Infof("StartWorkflowExecution: response: %v \n", *we.RunId)
+
+	workflowComplete := false
+	activitiesScheduled := false
+	activitiesMap := map[int64]*workflow.HistoryEvent{}
+	failWorkflow := false
+	failReason := ""
+	var activityATimedout bool
+	var activityALastHeartbeat int
+	dtHandler := func(execution *workflow.WorkflowExecution, wt *workflow.WorkflowType,
+		previousStartedEventID, startedEventID int64, history *workflow.History) ([]byte, []*workflow.Decision, error) {
+		if !activitiesScheduled {
+			activitiesScheduled = true
+			return nil, []*workflow.Decision{{
+				DecisionType: common.DecisionTypePtr(workflow.DecisionTypeScheduleActivityTask),
+				ScheduleActivityTaskDecisionAttributes: &workflow.ScheduleActivityTaskDecisionAttributes{
+					ActivityId:   common.StringPtr("A"),
+					ActivityType: &workflow.ActivityType{Name: common.StringPtr(activityName)},
+					TaskList:     &workflow.TaskList{Name: &tl},
+					Input:        []byte("Heartbeat"),
+					ScheduleToCloseTimeoutSeconds: common.Int32Ptr(35),
+					ScheduleToStartTimeoutSeconds: common.Int32Ptr(20),
+					StartToCloseTimeoutSeconds:    common.Int32Ptr(15),
+					HeartbeatTimeoutSeconds:       common.Int32Ptr(3), // ActivityID A is expected to timeout using Heartbeat
+				},
+			}}, nil
+		} else if previousStartedEventID > 0 {
+			for _, event := range history.Events[previousStartedEventID:] {
+				if event.GetEventType() == workflow.EventTypeActivityTaskScheduled {
+					activitiesMap[event.GetEventId()] = event
+				}
+
+				if event.GetEventType() == workflow.EventTypeActivityTaskTimedOut {
+					timeoutEvent := event.ActivityTaskTimedOutEventAttributes
+					scheduledEvent, ok := activitiesMap[timeoutEvent.GetScheduledEventId()]
+					if !ok {
+						return nil, []*workflow.Decision{{
+							DecisionType: common.DecisionTypePtr(workflow.DecisionTypeFailWorkflowExecution),
+							FailWorkflowExecutionDecisionAttributes: &workflow.FailWorkflowExecutionDecisionAttributes{
+								Reason: common.StringPtr("ScheduledEvent not found."),
+							},
+						}}, nil
+					}
+
+					switch timeoutEvent.GetTimeoutType() {
+					case workflow.TimeoutTypeHeartbeat:
+						if scheduledEvent.ActivityTaskScheduledEventAttributes.GetActivityId() == "A" {
+							activityATimedout = true
+							activityALastHeartbeat, _ = strconv.Atoi(string(timeoutEvent.Details))
+						} else {
+							failWorkflow = true
+							failReason = "ActivityID A is expected to timeout with Heartbeat"
+						}
+					}
+				}
+			}
+		}
+
+		if failWorkflow {
+			s.logger.Errorf("Failing workflow.")
+			workflowComplete = true
+			return nil, []*workflow.Decision{{
+				DecisionType: common.DecisionTypePtr(workflow.DecisionTypeFailWorkflowExecution),
+				FailWorkflowExecutionDecisionAttributes: &workflow.FailWorkflowExecutionDecisionAttributes{
+					Reason: common.StringPtr(failReason),
+				},
+			}}, nil
+		}
+
+		if activityATimedout {
+			s.logger.Info("Completing Workflow.")
+			workflowComplete = true
+			return nil, []*workflow.Decision{{
+				DecisionType: common.DecisionTypePtr(workflow.DecisionTypeCompleteWorkflowExecution),
+				CompleteWorkflowExecutionDecisionAttributes: &workflow.CompleteWorkflowExecutionDecisionAttributes{
+					Result: []byte("Done."),
+				},
+			}}, nil
+		}
+
+		return nil, []*workflow.Decision{}, nil
+	}
+
+	atHandler := func(execution *workflow.WorkflowExecution, activityType *workflow.ActivityType,
+		activityID string, input []byte, taskToken []byte) ([]byte, bool, error) {
+		s.Equal(id, *execution.WorkflowId)
+		s.Equal(activityName, *activityType.Name)
+		timeoutType := string(input)
+		switch timeoutType {
+		case "Heartbeat":
+			s.logger.Info("Starting hearbeat activity.")
+			go func() {
+				for i := 0; i < 6; i++ {
+					s.logger.Infof("Heartbeating for activity: %s, count: %d", activityID, i)
+					_, err := s.engine.RecordActivityTaskHeartbeat(createContext(), &workflow.RecordActivityTaskHeartbeatRequest{
+						TaskToken: taskToken, Details: []byte(strconv.Itoa(i))})
+					s.Nil(err)
+					time.Sleep(1 * time.Second)
+				}
+				s.logger.Info("End Heartbeating.")
+			}()
+			s.logger.Info("Sleeping hearbeat activity.")
+			time.Sleep(12 * time.Second)
+		}
+
+		return []byte("Activity Result."), false, nil
+	}
+
+	poller := &taskPoller{
+		engine:          s.engine,
+		domain:          s.domainName,
+		taskList:        taskList,
+		identity:        identity,
+		decisionHandler: dtHandler,
+		activityHandler: atHandler,
+		logger:          s.logger,
+		suite:           s,
+	}
+
+	_, err := poller.pollAndProcessDecisionTask(false, false)
+	s.True(err == nil || err == matching.ErrNoTasks)
+
+	for i := 0; i < 1; i++ {
+		go func() {
+			err = poller.pollAndProcessActivityTask(false)
+			s.logger.Infof("Activity Processing Completed.  Error: %v", err)
+		}()
+	}
+
+	s.logger.Infof("Waiting for workflow to complete: RunId: %v", *we.RunId)
+	for i := 0; i < 10; i++ {
+		s.logger.Infof("Processing decision task: %v", i)
+		_, err := poller.pollAndProcessDecisionTask(false, false)
+		s.Nil(err, "Poll for decision task failed.")
+
+		if workflowComplete {
+			break
+		}
+	}
+
+	s.printWorkflowHistory(s.domainName, &workflow.WorkflowExecution{
+		WorkflowId: common.StringPtr(id),
+		RunId:      common.StringPtr(we.GetRunId()),
+	})
+	s.True(workflowComplete)
+	s.True(activityATimedout)
+	s.Equal(5, activityALastHeartbeat)
+}
+
 func (s *integrationSuite) TestSequential_UserTimers() {
 	id := "interation-sequential-user-timers-test"
 	wt := "interation-sequential-user-timers-test-type"
diff --git a/service/history/timerBuilder.go b/service/history/timerBuilder.go
index e9912a9b750..5afdb5a4a30 100644
--- a/service/history/timerBuilder.go
+++ b/service/history/timerBuilder.go
@@ -289,7 +289,7 @@ func (tb *timerBuilder) loadActivityTimers(msBuilder *mutableStateBuilder) {
 				td := &timerDetails{
 					TimerSequenceID: TimerSequenceID{VisibilityTimestamp: startToCloseExpiry},
 					ActivityID:      v.ScheduleID,
-					EventID:         v.StartedID,
+					EventID:         v.ScheduleID,
 					TimeoutType:     w.TimeoutTypeStartToClose,
 					TimeoutSec:      v.StartToCloseTimeout,
 					TaskCreated:     (v.TimerTaskStatus & TimerTaskStatusCreatedStartToClose) != 0}
@@ -303,7 +303,7 @@ func (tb *timerBuilder) loadActivityTimers(msBuilder *mutableStateBuilder) {
 					td := &timerDetails{
 						TimerSequenceID: TimerSequenceID{VisibilityTimestamp: heartBeatExpiry},
 						ActivityID:      v.ScheduleID,
-						EventID:         v.StartedID,
+						EventID:         v.ScheduleID,
 						TimeoutType:     w.TimeoutTypeHeartbeat,
 						TimeoutSec:      v.HeartbeatTimeout,
 						TaskCreated:     (v.TimerTaskStatus & TimerTaskStatusCreatedHeartbeat) != 0}