[Biosensors and rate-responsive cardiac pacing].

Patients with atrioventricular block and ventricular pacemakers at a fixed rate have their exercise ability limited. This situation has been solved through dual chamber pacing in those patients keeping an adequate sinus node function. For the remaining, showing chronotropic failure or atrial fibrillation, the ability to increase their pacing rate is only possible when signals other than atrial activity, and reflecting metabolic needs, are used as a guide. These signals detected by a sensor, act through an algorithm modifying the pacing rate and are the cornerstone of rate-responsive pacing. Indications for these stimulation modes are analyzed as so are characteristics of different sensors used for this aim (pH, respiratory rate, QT interval, body activity, minute respiratory volume, central venous pressure, preejection period + stroke volume, right ventricular dp/dt, evoked QRS response and venous oxygen saturation).