Different systems (pulmonary impedance, pulmonary artery pressure, etc) are under investigation for haemodynamic monitoring. Their accuracy, long term stability, and autonomy seem adequate. Different studies (CHRONICLE phase 1 and ICD) have tested the benefits of these devices, which proved an event and hospital admission reduction in those patient who had these systems implemented. An increase in the pulmonary artery pressure was demonstrated 3-4 days before hospital admission because of heart failure symptoms in some of these studies.
Implantable loop recorders (ILR) can be used for both diagnostic purposes or risk stratification. The problems for diagnosis is the monitoring duration needed and the event occurrence. At the same time, ILR for diagnosis have the risk of severe arrhythmia occurrence and trauma. The ISSUE trial followed patients with syncope and structural heart disease with only slight depression of the left ventricular ejection fraction, and negative electrophysiological testing. Patients in this study show a good mid-term prognosis, recurrent syncope has an arrhythmic mechanism in around 50% of patients, and there was a wide spectrum of arrhythmias, which makes important and relatively safe to wait for diagnosis in this type of patients. ILR for risk stratification may play a role in the future but there is need of big trials to establish the true value of these devices for this purpose.
Telemonitoring, which may be the manual or automatic transmission of data or symptoms, is a promising area which is expected to grow to the extent of representing around 5% of total health care expenditure. Several trials showed a reduction in hospital admissions, but the benefits in survival and large trials are less clear.
Finally, left ventricular assist devices can be used as a bridge for heart transplantation or as end-stage devices. The major problems of the latest generation of these devices continue to be infection, bleeding, and embolism. It is clear that they improve survival but the cost is very high and should be decreased in the future.