Patent ID: 7890167

Claim:
A system comprising: a first implantable energy delivery circuit, configured to deliver a nondefibrillating and nonfibrillation-inducing energy to a first thoracic region, wherein the first energy delivery circuit is configured to deliver the energy to the first thoracic region that includes a location in, on, or near at least one of a right ventricle of the heart, a superior vena cava, an internal pectoral region, and an internal abdominal region; a first implantable electric field detector, configured to detect a first electric field at a second thoracic region including a location in, on, or near at least one of a left apical region of the heart and a left ventricular free lateral wall of the heart; a second implantable electric field detector, configured to detect a second electric field between a third thoracic region, which includes a location at or near at least a portion of the first thoracic region, and a fourth thoracic region, which includes a location at or near at least a portion of the second thoracic region; and an implantable or external controller, communicatively coupled to the first energy delivery circuit, the first electric field detector, and the second electric field detector, wherein the controller is configured to calculate an estimated defibrillation threshold using the delivered energy, the detected first electric field, and the detected second electric field, wherein the estimated defibrillation threshold includes a first estimated defibrillation threshold (“VDFT 1 est ”) calculated using VDFT ⁢ ⁢ 1 est = V 1 ⁢ A ∇ V ⁢ ⁢ 2 ⁢ f ⁡ ( V 3 - 4 ) , wherein V 1 includes a value of the delivered first energy, A is a desired, or “target”, electric field strength, ∇V 2 includes the detected first electric field, and V 3-4 includes the detected second electric field, wherein f(V 3-4 ) is configured to adjust the ratio of V 1 , A, and ∇V 2 .