A heart block is a condition when the electrical impulses that control the beating of the heart muscle are disrupted. The most serious type of heart block known as a complete heart block will have symptoms such as shortness of breath, irregular heartbeat or dizzy spells.
The contractions of the heart are triggered by electrical impulses generated by a group of specialised cells known as the sinoatrial node (SA node). The SA node generates electrical impulses at regular intervals which are sent to another group of cells called the atrioventricular node (AV node). The AV node conducts the impulse into the ventricles, which are the two lower chambers of the heart.
A heart block does not stop the heart from beating altogether, but it can result in an abnormally slow heartbeat (bradycardia) that causes the organs to be deprived of oxygen. It is estimated that 5-10% of people who are over 70 years of age will develop complete heart block, particularly if they have a history of heart disease.
The outlook for all types of heart block is very good as long as appropriate treatment is given. Heart block responds very well to treatment with a pacemaker, and deaths that are caused by these conditions are very rare.
A pacemaker is a small device with electrodes that stimulate the heart. It is implanted by a cardiac team consisting of a surgeon, an anesthetist, and nurses that prepare the surgical area. The patient is only given partial anesthesia so the action of the heart can be monitored during the operation. The patient is conscious and can feel when the doctor makes the incision below the clavicle and when the electrodes are positioned next to the heart. The anesthesia dulls the pain, but the patient is alert enough to know when the doctor stitches the incision. After the operation, the anesthesia tent over the head is removed and the patient is held for observation for a few minutes. If there are no complications, the patient is released from the hospital the next day.