Cardiac tamponade is a deadly condition that can lead to a sudden heart failure of a previously completely healthy heart muscle.
Heart is located in the chest within a bag-like structure known as the pericardium. Between the wall of the heart and pericardium, there is only a small space filled with only a trace amount of liquid. The pericardium is stretchable and the minimal amount of liquid does not restrict the pumping functions of the heart. Under certain circumstances, however, the fluid may accumulate within pericardium. This may compress the heart, disrupt its function and cause the cardiovascular shock.
There are many factors that cause the accumulation of fluid in the pericardium. Here are mentioned the most common ones:
Inflammation of the pericardium may be accompanied by the emergence of fluid in the pericardial space. Small quantity of fluid has no symptoms, but larger amount may cause cardiac failure. There are many possible causes of pericarditis including autoimmune diseases, cancers, underactive thyroid gland, heart attack, uremia in chronic renal failure, etc.). Further details of pericarditis can be found in the related article.
Rupture of the heart wall
The heart wall may be perforated by an extensive myocardial damage. It can follow a massive heart attack being its rare, but a deadly complication. Myocardial wall may be also damaged by a stab wound. This caused the death of the well-known Empress Sissi when an assassin pierced her heart with a sharpened file. However, the hole in the pericardium almost closed and the blood leakage into the pericardium was very slow. Therefore, the Empress was unaware of her injury and continued to walk (thinking that she was just harmlessly hit by a careless passer-by) and collapsed after a few tens of meters when cardiac tamponade developed. The risk of cardiac tamponade is also higher in all invasive medical procedures that are performed in the chest near the heart.
The fluid in the pericardium is initially asymptomatic, but as its volume increases, it begins to compress the heart muscle from the outside and interferes with its pumping action. The resulting symptoms are typical for shock conditions – rapid pulse, low blood pressure and pallor. The pulse and blood pressure are in this case dependable on breathing. During inspiration, the blood pressure drops significantly and the pulse is poorly palpable. This is due to the fact that when you inspire, the lungs expand and compress the heart even more.
The compressed heart is unable to handle the volume of blood brought in by veins and the blood accumulates in large veins in front of the heart. This can be best seen in the neck veins that are visibly filled with blood right under the skin. When the circulation fails, the brain loses oxygen supply and this is followed by coma and death.
An experienced doctor may get suspicion from the above-mentioned symptoms and clinical signs. The fluid within the pericardium can be diagnosed by echocardiography. However, when the condition is acute, there may be not enough time for the diagnostics.
The treatment must be rapid and aggressive. The only effective method is a puncture of the chest into the pericardial sac, which allows draining the fluid and saving the heart. The procedure is familiar for intensive care physicians, but not for the rest of medical staff.