Right atrium indicator

1. A method for determining the location of a medical device within a body, the method comprising:

transmitting from the medical device an acoustic signal;

receiving with the medical device a reflected acoustic signal;

advancing the medical device based on a first algorithm, the first algorithm including a first weighting factor and a first feature extracted from the reflected acoustic signal;

determining a first location of the medical device based on the first algorithm; and

moving the medical device to a second location based on a second algorithm, the second algorithm based on the determined first location and including at least one of a second weighting factor and a second feature extracted from the reflected acoustic signal.

2. The method of claim 1 , further comprising detecting an ECG signal, wherein the first algorithm includes a third feature extracted from the ECG signal.

3. The method of claim 2 , wherein the third feature is the R-wave of the ECG signal.

4. A method for guiding a medical device to a target location within a patient's cardiovascular system, the method comprising:

transmitting from the medical device an acoustic signal;

receiving with the medical device a reflected acoustic signal;

extracting one or more features indicative of blood flow characteristics from the acoustic signal;

determining a plurality of scores for a plurality of membership functions, each membership function comprising a series of extracted features, each extracted feature modified by a weighting factor, wherein the plurality of membership functions include at least one membership function for the target location within the cardiovascular system, at least one membership function for moving the device within the cardiovascular system, and at least one membership function for a secondary location within the cardiovascular system; and

changing at least one weighting factor or at least one extracted feature in the series of extracted features of at least one membership function when the score of the membership function for the secondary location within the cardiovascular system is the greatest score.

5. The method of claim 4 , wherein the target location is the SVC.

6. The method of claim 4 , wherein the secondary location is the right atrium.

7. A system for determining the location of a medical device within a body, the system comprising:

an elongate body having an non-imaging ultrasound transducer disposed on a distal portion of the elongate body;

a processor configured to receive and process a reflected acoustic signal from the non-imaging ultrasound transducer; and

memory for storing instructions, which when executed by the processor, causes the processor to:

provide instructions to advance the elongate body based on a first algorithm, the first algorithm including a first weighting factor and a first feature extracted from the reflected acoustic signal;

determine a first location of the elongate body based on the first algorithm; and

provide instructions to move the elongate body to a second location based on a second algorithm, the second algorithm based on the determined first location and including at least one of a second weighting factor and a second feature extracted from the reflected acoustic signal.