Aims: Heart failure has a relevant healthcare impact. Monitoring of pulmonary fluid overload (PFO), measured by intrathoracic impedance, has been proposed to alert to heart failure worsening before symptoms become patent. The aim of our research was to evaluate whether PFO diagnostics reduce heart failure hospitalizations in heart failure patients receiving single-chamber or dual-chamber implantable cardioverter-defibrillator (ICD) for primary prevention of sudden death.
Methods: Twenty-five Italian cardiological centers prospectively followed 221 ICD patients (86% men, 66 ± 11 years, 79% New York Heart Association II and left ventricular ejection fraction 28 ± 5%), of whom 123 received an ICD with PFO monitoring (diagnostics group) and 98 an ICD without such a diagnostics (control group). The association of each patient to a group was assigned a priori, independently of patients' characteristics but based on regional device allocation policies.
Results: Patient clinical characteristics and observation period were similar between groups. In a mean follow-up of 17 ± 11 months, heart failure hospitalizations or emergency-room admissions occurred in eight (7%) patients of the diagnostics group and in 16 of the control group (16%; P = 0.02), with an incidence, measured by Kaplan-Meier analysis, of 23% at 2 years and 34% at 3 years in patients of the control group compared with 8% at 2 and 3 years in patients of the diagnostics group (Log rank test P = 0.044).
Conclusion: Our data show that in heart failure patients receiving single-chamber or dual-chamber ICD, the use of intrathoracic impedance monitoring is associated with a significant reduction of heart failure hospitalizations. Our results support the hypothesis that PFO diagnostics improve the likelihood of timely detection of heart failure worsening.