1998c-056 2007i-817 2017e-877 arrhythmias artificial cardiac cardiacpacemakers cardiacpacing cardiacresynchronizationtherapy cardiacresynchronizationtherapydevices congestiveheartfailure defibrillators electrocardiography general heartfailure implantable medical methods pacemaker programmedinstruction surgery therapy wg168 wg330j82i2007 wg370c26732008