An endovascular access and guidance system, comprising: an elongate body with a proximal end and a distal end; a non-imaging ultrasound transducer on the elongate body configured to provide in vivo non-image based ultrasound information of the vasculature of the patient; an endovascular electrogram lead on the elongate body in a position that, when the elongate body is in the vasculature, the endovascular electrogram lead electrical sensing segment provides an in vivo electrogram signal of the patient; a processor configured to: receive and process at least one signal from the non-imaging ultrasound transducer selected from the group consisting of: a venous blood flow direction, a venous blood flow velocity, a venous blood flow signature pattern, a pressure signature pattern, A-mode information and a preferential non-random direction of flow, receive and process at least one signal from the endovascular electrogram lead selected from the group consisting of: an electrocardiogram signal, a P-wave pattern, a QRS-complex pattern, a T-wave pattern, an EEG signal and an EMG signal, and provide information regarding the position of the elongate body within the venous vasculature based on the in vivo non-image based ultrasound signal information and the in vivo electrogram signal information that is processed; and an output device configured to display a result of information processed by the processor, said result related to the determined position of the elongate body within the venous vasculature. an elongate body with a proximal end and a distal end; a non-imaging ultrasound transducer on the elongate body configured to provide in vivo non-image based ultrasound information of the vasculature of the patient; an endovascular electrogram lead on the elongate body in a position that, when the elongate body is in the vasculature, the endovascular electrogram lead electrical sensing segment provides an in vivo electrogram signal of the patient; a processor configured to: receive and process at least one signal from the non-imaging ultrasound transducer selected from the group consisting of: a venous blood flow direction, a venous blood flow velocity, a venous blood flow signature pattern, a pressure signature pattern, A-mode information and a preferential non-random direction of flow, receive and process at least one signal from the endovascular electrogram lead selected from the group consisting of: an electrocardiogram signal, a P-wave pattern, a QRS-complex pattern, a T-wave pattern, an EEG signal and an EMG signal, and provide information regarding the position of the elongate body within the venous vasculature based on the in vivo non-image based ultrasound signal information and the in vivo electrogram signal information that is processed; and receive and process at least one signal from the non-imaging ultrasound transducer selected from the group consisting of: a venous blood flow direction, a venous blood flow velocity, a venous blood flow signature pattern, a pressure signature pattern, A-mode information and a preferential non-random direction of flow, receive and process at least one signal from the endovascular electrogram lead selected from the group consisting of: an electrocardiogram signal, a P-wave pattern, a QRS-complex pattern, a T-wave pattern, an EEG signal and an EMG signal, and provide information regarding the position of the elongate body within the venous vasculature based on the in vivo non-image based ultrasound signal information and the in vivo electrogram signal information that is processed; and an output device configured to display a result of information processed by the processor, said result related to the determined position of the elongate body within the venous vasculature.