Ability of Home Monitoring® to Detect and Manage the Inappropriate Diagnoses in Implantable Cardioverter Defibrillators. (THORN)

• Relative proportion of patients experiencing at least one inappropriate therapy (retrospective part) or more than one inappropriate therapy (prospective part) [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  Study of the relationship between the detection of ID, the corrective action taken and the recurrence of ID of the same mechanism.
  
  

• Number of diagnoses per patient per year and relative proportion of patients with at least one diagnosis [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]

  The number of diagnoses per patient per year and the associated proportion of patients (with at least one diagnosis) will be measured. This will give the incidence rate of experiencing special classes of diagnoses over the 15-months follow-up period. The following subclasses will be assessed:

  Appropriate or not diagnoses, ID without therapy, therapies defined as shocks or antitachycardia pacing (ATP), shocks, inappropriate shocks, recurrence of ID and recurrence of inappropriate shocks.

  The prospective part will be compared to the retrospective part.

  
  
• Relative proportion of patients with a second day of ID [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]

  Knowing that the intervals between ID days cannot be predetermined (non normal distribution), medical reaction time anticipated with Home Monitoring® can reduce the number of patients with a second day of ID.

  The proportion of patients with more than one inappropriate diagnosis will be measured.

  
  
• Number of Asymptomatic Inappropriate therapy and Inappropriate therapy without diagnosis [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  Knowing that the main added value of Home Monitoring® relates on asymptomatic inappropriate therapies and inappropriate diagnoses without therapy (IDWT), the number of asymptomatic IT or IDWT patient per year and the associated proportion of patients (with at least one inappropriate diagnosis) will be measured.
  
  
• Time to the first ID [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  The time from the enrolment until the first EGM revealing the ID will be assessed.
  
  
• Medical reaction time to the ID [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]

  The time from the first ID to the follow-up visit during which a corrective action is taken is defined as the medical reaction time and will be assessed.

  In case of hospitalization without a follow-up visit (lead replacement for instance), the first day of hospitalization will be considered as the follow-up visit date.

  In current practice, the patients receiving shocks are advised to call their physicians in order to have their ICD interrogated. The analysis will distinguish the symptomatic IT and the asymptomatic ID (asymptomatic IT or IDWT).

  
  
• Number of days of recurrence within the medical reaction time [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  The number of days with at least one ID within the medical reaction time is defined as the number of days of recurrence and will be evaluated with the associated proportion of patients. The analysis will distinguish the symptomatic IT and the asymptomatic ID (asymptomatic IT or IDWT).
  
  
• Effectiveness of the corrective action and analysis according to the initial ID type [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]

  The proportion of patients with at least one inappropriate diagnosis recurrence (first day of recurrence) after the corrective action, and with the same ID mechanism as the original one, will be evaluated.

  A subgroup analysis depending on the ID mechanism will be performed, considering the inhomogeneous efficiency of the corrective action depending on the initial mechanism of the inappropriate diagnosis/therapy .

  The time from the follow-up visit during which the corrective action is taken until the next ID will be measured to assess the effectiveness of the corrective action.

  
  
• Classification of ID [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]

  The proportion of patient in the following classes of ID episodes will be evaluated:

  • Atrial fibrillation,
  • Other forms of supraventricular tachyarrhythmia
  • Sinus tachycardia
  • Abnormal sensing (T wave oversensing, interferences,…)
  • Other: the comparison is performed as an inter observer comparison between the Adjudication Board's and the physician's classification.
  
  
• Total number of hospitalizations/deaths related to ID and IT [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  Knowing that inappropriate therapies are among the heaviest ICD side-effects, the total number of hospitalizations and deaths related to ID or IT will be assessed.
  
  
• Risk of all-cause mortality [ Time Frame: 15 months ] [ Designated as safety issue: Yes ]
  The risk of death associated with inappropriate therapy only, with the inappropriate shocks only, with any shocks, without any therapy, without any shocks will be evaluated.
  
  

Remote Patient Monitoring allows early detection of events that can generate inadequate detection of ventricular arrhythmia (i.e. lead rupture, atrial arrhythmia, oversensing….) and be responsible for inappropriate therapies. In such cases, it may be assumed that physicians can react earlier and take preventive actions, in order to reduce the risk or burden of inappropriate therapies.

The THORN registry has two purposes:

• To determine retrospectively the relative proportion of patients experiencing at least one inappropriate therapy during 15-months of follow-up, in ICD patients equipped with Home Monitoring®. This part concern 1240 patients.
• To evaluate prospectively the relationship between the detection of inappropriate diagnosis (with or without subsequent inappropriate therapy), the corrective action taken, and the recurrences of inappropriate diagnosis of the same origin/mechanism. This part concerns 510 patients.

BIOTRONIK Home Monitoring® by IEGM-Online® with LUMAX ICD devices systematically stores any episode classified as ventricular tachycardia (VT) or ventricular fibrillation (VF) which is transmitted to the physician.

In the THORN study, in addition to the physicians' analysis, all electromyograms will be reviewed by an adjudication committee in order to classify them as appropriate or inappropriate diagnosis.