An anatomical mapping system comprising: a plurality of mapping electrodes configured to detect electrical activation signals of intrinsic physiological activity within an anatomical structure wherein activation signals are detected as electrical signals; a plurality of mechanical sensors and a reference mechanical sensor, wherein the reference mechanical sensor is disposed outside of the anatomical structure and not influenced by the mechanical activity in the anatomical structure, the mechanical sensors and the reference mechanical senor are configured to detect mechanical activity associated with the intrinsic physiological activity, wherein each of the plurality of mechanical sensors and the reference mechanical sensor is a piezoelectric sensor or crystal, wherein the mechanical sensors are configured to transmit ultrasonic signals related to the mechanical activity and the reference mechanical sensor is configured to receive the ultrasonic signals; and a mapping processor, electrically coupled to the plurality of mapping electrodes and electrically coupled to the mechanical sensors, the mapping processor configured to receive electrical signals from the mapping electrodes, the mechanical sensors, and the reference mechanical sensor that are indicative of the detected electrical activation signals and the electrical signals indicative of the detected local mechanical activity; record the detected electrical activation signals; and associate one of the plurality of mapping electrodes and mechanical sensors with each recorded detected electrical activation signal, the mapping processor further configured to determine activation times of the intrinsic physiological activity based on a correlation of corresponding electrical activation signals and mechanical activity, wherein the mapping processor is further configured to generate, for each determined activation time, a reliability index of the corresponding correlation, wherein each reliability index is based on the correlated mechanical activity and a spatial proximity of the corresponding mechanical sensor relative to the detecting mapping electrode. a plurality of mapping electrodes configured to detect electrical activation signals of intrinsic physiological activity within an anatomical structure wherein activation signals are detected as electrical signals; a plurality of mechanical sensors and a reference mechanical sensor, wherein the reference mechanical sensor is disposed outside of the anatomical structure and not influenced by the mechanical activity in the anatomical structure, the mechanical sensors and the reference mechanical senor are configured to detect mechanical activity associated with the intrinsic physiological activity, wherein each of the plurality of mechanical sensors and the reference mechanical sensor is a piezoelectric sensor or crystal, wherein the mechanical sensors are configured to transmit ultrasonic signals related to the mechanical activity and the reference mechanical sensor is configured to receive the ultrasonic signals; and a mapping processor, electrically coupled to the plurality of mapping electrodes and electrically coupled to the mechanical sensors, the mapping processor configured to receive electrical signals from the mapping electrodes, the mechanical sensors, and the reference mechanical sensor that are indicative of the detected electrical activation signals and the electrical signals indicative of the detected local mechanical activity; record the detected electrical activation signals; and associate one of the plurality of mapping electrodes and mechanical sensors with each recorded detected electrical activation signal, the mapping processor further configured to determine activation times of the intrinsic physiological activity based on a correlation of corresponding electrical activation signals and mechanical activity, wherein the mapping processor is further configured to generate, for each determined activation time, a reliability index of the corresponding correlation, wherein each reliability index is based on the correlated mechanical activity and a spatial proximity of the corresponding mechanical sensor relative to the detecting mapping electrode.