Pain free defibrillation threshold estimation

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 controller is configured to calculate an initial estimated defibrillation threshold using the delivered energy and the detected first electric field, and to calculate an adjusted estimated defibrillation threshold using the initial estimated defibrillation threshold and the detected second electric field.

A method comprising:

• delivering a first nondefibrillating and nonfibrillation-inducing energy to at least one first thoracic region using a first implantable energy delivery circuit, wherein delivering the first energy includes delivering the first energy 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;
• detecting a first electric field at at least one second thoracic region using a first implantable electric field detector 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;
• detecting a second electric field between a third thoracic region, which is at or near the at least one first thoracic region, and a fourth thoracic region, which is at or near the at least one second thoracic region, using a second implantable electric field detector;
• and
• calculating, using an implantable or external controller, an estimated defibrillation threshold using the delivered first energy, the detected first electric field, and the detected second electric field, wherein calculating the estimated defibrillation threshold includes calculating a first estimated defibrillation threshold (“VDFT1est”) using
• VDFT
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• A
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• f
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• wherein V1 includes the delivered first energy, A is a desired, or “target”, electric field strength, ∇V2 includes a signal indicative of the detected first electric field, and V3-4 includes a signal indicative of the detected second electric field, wherein f(V3-4) is configured to adjust the ratio of V1, A, and ∇V2.

A method comprising:

• delivering a first nondefibrillating and nonfibrillation-inducing energy to at least one first thoracic region using a first implantable energy delivery circuit, wherein delivering the first energy includes delivering the first energy 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;
• detecting a first electric field at at least one second thoracic region using a first implantable electric field detector 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;
• detecting a second electric field between a third thoracic region, which is at or near the at least one first thoracic region, and a fourth thoracic region, which is at or near the at least one second thoracic region, using a second implantable electric field detector;
• and
• calculating, using an implantable or external controller, an estimated defibrillation threshold using the delivered first energy, the detected first electric field, and the detected second electric field, wherein calculating the estimated defibrillation threshold includes calculating an initial estimated defibrillation threshold using the delivered first energy and the detected first electric field, the method further including calculating an adjusted estimated defibrillation threshold using the initial estimated defibrillation threshold and the detected second field.