This 42-year-old man received a Lumax 340 HF-T triple chamber defibrillator for primary prevention in the context of dilated cardiomyopathy with a 20% left ventricular ejection fraction and left bundle branch block. He was monitored by telecardiology and, 3 years after device implantation, an alert message was delivered
Telemedicine report
Alert message (yellow status) for a long classified episode of atrial monitoring and decrease in the percentage of biventricular stimulation below the lower limit of 85%. This patient developed several episodes of atrial fibrillation (increase in atrial fibrillation burden) with mode switch. Before the arrhythmia became permanent, several mode switches occurred without prominent increase in the atrial fibrillation burden, indicating that the arrhythmic episodes were brief. Simultaneously, the percentage of atrial stimulation decreased as the atrial rate increased progressively. As the atrial fibrillation burden increased, the spontaneous ventricular rate increased, (proof of a preserved atrioventricular conduction) with a sudden decrease in the percentage of biventricular stimulation. The analysis of the remotely transmitted tracing confirmed the development of atrial fibrillation conducted through the atrioventricular node, with a rapid ventricular rate and loss of biventricular resynchronization. A close review of all the information gathered in these various panels, allowed a reconstitution of the patient’s history.
An important contribution of telemedicine consists in the ambulatory surveillance of chronic diseases. Heart failure is the main indication for the implantation of a defibrillator. Its prevalence keeps increasing, involving 1-2% of the Western populations. State-of-the-art devices are capable of analysing multiple physiologic measurements, including thoracic impedance, heart rate variability, resting and exercise heart rate and activity level, allowing the monitoring of the device recipient’s hemodynamic status. The role of telemedicine is probably not to decrease the number of ambulatory visits for the management of heart failure, as they are needed for the clinical and echocardiographic follow-up of the patient. On the other hand, telemedicine optimizes the follow up by analysing the variations in these measurements, enabling an early detection of hemodynamic deteriorations. The prevention of re-hospitalization is a major objective of the delivery of public healthcare, and of remote monitoring. Studies have shown that the early manifestations of heart failure develop between 8 and 12 days before hospitalization. Telemedicine allows an early detection of the signs of impending cardiac decompensation, before the patient can no longer be treated in an ambulatory setting.
With respect to the follow-up of cardiac resynchronization, telemedicine contributes also some key information. In this patient the development of atrial fibrillation was responsible for the loss of biventricular stimulation, interfering with the efficacy of resynchronization. A threshold for the minimum percentage of biventricular stimulation is programmable. Various studies have found that this threshold needs to be near 100%. Different measures could be considered for this patient: 1) Control of the heart rate by pharmaceutical treatment or by ablation of the atrioventricular junction; or 2) control of the rhythm. This patient had been treated with amiodarone in the past, and no new drug treatment seemed appropriate. Consequently, he underwent ablation of the pulmonary veins.
Whichever the chosen strategy, telemedicine optimizes the subsequent follow-up, by analysing the mean and maximal heart rate if a strategy of rate control was chosen, and by the detection of arrhythmic recurrences if a strategy of rhythm control was adopted.