Techniques for biventricular pacing include a rigid shaped stylet approximating curves of a coronary sinus and branch vein. Some techniques include a parasternal coronary sinus cannula comprising an outer sheath and an obturator. The obturator is removeably disposed inside the outer sheath from a device end of the hollow shaft. The obturator includes a flexible stem that fits snugly inside the hollow shaft, a malleable core disposed inside the flexible stem, a tapered tip that extends beyond a cardiac end of the shaft when the obturator is disposed inside the outer sheath, and a sensor for determining properties of the subject in a vicinity of the tapered tip. An optional pressure-seal, such as a tent, connected to suction maintains negative intrepleural pressure for insertion under local anesthesia.
