Updated December 15, 2014.

The following yoga poses are great for working on chest and heart opening. This area tends to be tight in people who spend long hours working at desks. Many, though not all, of these poses are also backbends. When back bending, especially for the purpose of heart opening, focus on incorporating the upper and middle parts of the spine, which are often under utilized because the low back tends to be more flexible.

The tips below are intended to maximize the heart-opening potential of each pose.

Beginners' Poses

Bridge Pose - Setu Bandha Sarvangasana
To emphasize and support your chest, tuck your shoulders under your body after you have lifted your hips. 

Cat - Cow Stretch
Use cat-cow as an exercise in contrast. By drawing your heart deep into your chest in the cat position, you can more fully expand it in the cow position.

Cobra Pose - Bhujangasana
Roll your shoulders back and keep them away from your ears. Stay in the pose for several breaths, trying to lift your chest without pressing into your hands.

Extended Side Angle Pose - Utthita Parsvakonasana
As you raise your arm, turn your chest to face the ceiling as much as possible. 

Supine Spinal Twist - Supta Matsyandrasana
This twist offers a great opportunity to stretch the front of the chest. For the purpose of heart opening, concentrate on keep both your shoulders on the ground as much as possible. This may cause your knee to come off the floor, but that's ok.

Triangle Pose - Utthita Trikonasana
Much the same action as extended side angle pose, above. You can also try dropping your lifted arm behind your back and possibly catching hold of your inner thigh to increase the opening across your chest.

Warrior II - Virabhadrasana II
Roll your shoulder down and back to avoid hunching in this pose.

Intermediate 

Bound Extended Side Angle
If you can bind your arms behind your back in this pose, you will find that it give you some resistance into which you can deepen the rotation of your chest toward the ceiling.

Bow Pose – Dhanurasana
Catching ahold of your ankles in this prone backbend gives your heart opening some traction. Pull on the ankles with your arms at the same time that you push the feet away from you.

Camel Pose - Ustrasana
This is a nice option for people with tight shoulders. Use blocks under your hands if it's hard for you to reach your ankles. Imagine a string pulling your sternum toward the ceiling.

Fish Pose - Matsyasana
Try fish pose with a block between your shoulder blades to support your backbend.

Half Moon Pose - Ardha Chandrasana
Make sure that raising your arm is the result of the opening of your chest to the ceiling. It's easy just to lift your arm but keep your chest angled toward the floor. Rotate your chest fully before you raise your arm.

Locust Pose – Shalabasana
Another opportunity to use a bind to deepen your pose. Clasp your hands behind your back and allow them to open your shoulders.

Reverse Warrior
Reverse warrior is such a complicated pose. For the purpose of heart opening, focus your attention on creating a slight backbend in your upper back and lifting your chest as you raise your arm. This may cause you to bring your bottom arm higher up your leg, but that's ok.

Upward Facing Dog - Urdhva Muhka Svanasana
Before straightening your arms, bend generously at the elbows and roll your shoulders back and down. You can even keep a slight bend in your arms if that helps you keep your shoulders back.

Advanced 

One-Legged King Pigeon Pose – Eka Pada Rajakapotasana
Full pigeon is a deep back bend. You can get some of the effects of this pose by looping a strap over your raised foot. 

Wheel Pose - Urdhva Dhanurasana
Focus on heart opening in wheel to take any strain out of your lower back.