Ventricular Dyssynchrony

The heart muscle is responsible for circulating blood throughout the body. The heart has four chambers, two upper (atrium) and two lower (ventricle), with one atrium and one ventricle on both the right and left side of the heart. Blood that is returning from other areas of the body and is no longer oxygen rich, enters through the top right chamber of the heart. That blood is then pumped into the right ventricle and through the pulmonary artery into the lungs to absorb more oxygen. This oxygen-rich blood is then pumped into the top-left chamber of the heart and then into the lower-left chamber before being pumped out into the body through the aorta.

For the heart to pump blood efficiently, all four chambers must work together and pump at the correct time. When the lower chambers of the heart, the ventricles, do not pump at the correct time or are out of sync, the condition is called ventricular dyssynchrony.

There are three main types of ventricular dyssynchrony:

  • Atrioventricular dyssynchrony - affecting the contraction between the atrium and ventricle
  • Interventricular dyssynchrony - affecting the contraction between the right and left ventricles
  • Intraventricular dyssynchrony - affecting the contraction of segments in the left ventricle wall

Symptoms

Ventricular dyssynchrony is associated with a patient experiencing heart failure. There are no physical symptoms that patients with ventricular dyssynchrony experience. However, they may experience symptoms of heart failure, as the two are closely linked.

Symptoms of heart failure may include:

  • A dry, hacking cough, especially when lying down
  • Confusion, sleepiness and disorientation in older people
  • Dizziness, fainting, fatigue or weakness
  • Fluid buildup, especially in the legs, ankles and feet
  • Increased urination at night
  • Nausea, abdominal swelling, tenderness or pain (may result from the buildup of fluid in the body and the backup of blood in the liver)
  • Weight gain (due to fluid buildup)
  • Weight loss as nausea causes a loss of appetite and as the body fails to absorb food well
  • Rapid breathing, bluish skin and feelings of restlessness, anxiety and suffocation
  • Shortness of breath and lung congestion as the blood backs up in the lungs
  • Tiring easily
  • Wheezing and spasms of the airways similar to asthma


Causes and Risk Factors

Ventricular dyssynchrony is caused by erratic electrical impulses that cause the chambers of the heart to pump out of sync. This limits the chambers from filling with blood as they normally would and causes the heart to work inefficiently. The condition is associated with patients who have been diagnosed with heart failure and is often caused by left bundle branch block.

Diagnosis

Diagnosis of ventricular dyssynchrony almost always occurs during or after the diagnosis of heart failure. An echocardiogram is a noninvasive procedure that uses ultrasound to create a moving picture of the heart as it works and is the most commonly used diagnostic tool for the condition.

An electrocardiogram (EKG) is another noninvasive procedure and may be used to examine the electrical activity of the heart.

Additional imaging tests such as a cardiac MRI or chest X-ray may be used to see if the heart is enlarged — if the echocardiogram is inconclusive.

Treatments

Treatment of ventricular dyssynchrony will focus on correcting the abnormal heart rhythm through cardiac resynchronization therapy and managing the symptoms of heart failure.

Cardiac resynchronization therapy, also known as biventricular pacing, works to regulate the abnormal heart rhythm by implanting a pacemaker just below the collarbone. The device monitors the heart rate to detect abnormal heart rhythms and emits small pulses of electricity to correct them. This method resynchronizes the heart and improves the output of blood from the heart because it coordinates the pumping of the lower left and right chambers. Less blood leaks through the mitral valve, and the muscles of the lower-left chamber can pump better.

Additional treatment options for patients experiencing heart failure include:

  • Medications - In most cases, patients with heart failure have the disease for the rest of their lives and require specific drugs. A combination of drugs may be used, including ACE inhibitors, diuretics, beta-blockers and digoxin. These do not cure heart failure. They can relieve symptoms, improve heart function, slow the progress of the disease and reduce the risk of complications, hospitalization and premature death.
  • Surgery - can open blocked blood vessels in the heart and restore normal blood flow. Surgery to correct certain types of heart valve disease may also improve symptoms of heart failure
  • Ventricular assist devices - These machines help a failing heart pump blood throughout the body. VADs have been used in patients as young as 7 years old and as old as 70.
  • Cardiac Mechanical Assist Device Program - This Cedars-Sinai Heart Institute program provides complete state-of-the-art mechanical support for patients with end-stage heart failure.
  • Heart transplant
  • Treating related problems - correct or control related health problems (such as high blood pressure or coronary artery disease) and any other heart failure triggers (such as fever, anemia or infection)
  • Lifestyle changes - losing weight, starting an exercise program approved by your doctor, reducing the amount of salt and fat in the diet, quitting smoking and avoiding alcohol

Heart failure that develops or gets worse quickly needs to be treated on an emergency basis in a hospital. If there is severe swelling in the lungs, oxygen will be given through a face mask. Diuretics can be injected, and drugs (such as nitroglycerin) can be given to improve comfort. In some cases it may be necessary to use a mechanical ventilator to assist in breathing. Certain hormones similar to adrenaline can be given on a short-term basis to help the heart muscle work more effectively.

The knowledgeable and highly trained staff at the Cedars-Sinai Heart Institute will work with each patient to determine the best treatment option.