Efficacy of Intrathoracic Impedance and Remote Monitoring in Patients With an Implantable Device After the 2011 Great East Japan Earthquake

Several studies have revealed that stress after catastrophic disasters can trigger cardiovascular events, however, little is known about its association with the occurrence of heart failure in past earthquakes. The objective of the present study was to determine whether the Great East Japan Earthquake on March 11, 2011, increased the incidence of worsening heart failure in chronic heart failure (CHF) patients with implantable devices. Furthermore, we examined whether intrathoracic impedance using remote monitoring was effective for the management of CHF. We enrolled 44 CHIP patients (32 males, mean age 63 +/- 12 years) with implantable devices that can check intrathoracic impedance using remote monitoring. We defined the worsening heart failure as accumulated impedance under reference impedance exceeding 60 ohms-days (fluid index threshold), and compared the incidence of worsening heart failure and arrhythmic events 30 days before and after March 11. Within the 30 days after March 11, 10 patients exceeded the threshold compared with only 2 patients in the preceding 30 days (P < 0.05). Although 9 patients using remote monitoring among the 10 patients with threshold crossings were not hospitalized, one patient without the system was hospitalized due to acute decompensated heart failure. On the contrary, arrhythmic events did not change between before and after March 11. Our results suggest that earthquake-induced stress causes an increased risk of worsening heart failure without changes in arrhythmia. Furthermore, intrathoracic impedance using remote monitoring may be a useful tool for the management of CHF in catastrophic disasters.