IVCD is not always serious and is not always dangerous as many people do have IVCD even with a normal and healthy heart.
Although, the seriousness of IVCD also depends on the exact type of delay, like right bundle branch block, left bundle branch block, or a non specific delay, and whether or not you have underlying heart disease or symptoms like dizziness.
If you feel fine and have no history of heart disease, minor or borderline delays, especially right bundle branch blocks, these are often harmless.
And many people live a full, normal life with an incidental IVCD and neve require treatment.
IVCD is a finding on an ECG (electrocardiogram) that shows the electrical signals travel slightly slower than normal through the lower chambers (ventricles) of your heart and it includes right bundle branch block (RBBB), left bundle branch block (LBBB), or a nonspecific intraventricular conduction delay (NIVCD).
IVCD, also known as intraventricular conduction delay, affects the heart by slowing the spread of electrical signals through your heart's ventricles.
This delay causes what is known as ventricular dyssynchrony, which is uncoordinated muscle contraction, making your heart pump less efficiently.
And on an ECG, the IVCD appears as a widened QRS complex.
Instead of squeezing all at once, parts of the left and the right ventricles contract out of sync, which reduces overall pumping power of the heart.
Your heart muscle also has to work harder to push blood out, which can worsen existing heart failure or even strain your heart over time.
And severe or nonspecific IVCDs or intraventricular conduction delays are also linked to a higher risk of irregular heartbeats (arrhythmias) and sudden cardiac events.
Common causes of IVCD or intraventricular conduction delays include certain medications or electrolyte imbalances like high potassium, high blood pressure or age related changes in your heart's conduction system, structural heart disease, cardiomyopathy, or even past heart attacks and even bundle branch blocks, like left or right bundle branch blocks.
IVCD means that the electrical signals travel too slowly through the lower chambers (ventricles) of your heart. On an electrocardiogram (ECG), this appears as a widened QRS complex (lasting 120 milliseconds or longer).
IVCD generally falls into three main categories which include:
Right Bundle Branch Block (RBBB): A delay in the right side of the heart.
It is often relatively benign in healthy people, though it can still point to lung or heart strain.
Left Bundle Branch Block (LBBB): A delay in the left side of the heart.
It is more frequently linked to underlying structural heart disease, high blood pressure, or coronary artery disease.
Nonspecific Intraventricular Conduction Delay (NIVCD or NSIVCD): A wide QRS pattern that does not fit neat RBBB or LBBB criteria.
Research also shows non-specific delays can sometimes carry a higher risk of adverse cardiac events or sudden arrhythmic death than standard bundle branch blocks.
If you have no symptoms and a normal heart structure, a mild IVCD (sometimes called an incomplete RBBB) can occasionally be a harmless normal variant.
If you have heart failure, a history of a heart attack, or cardiomyopathy, an IVCD significantly increases the risk of cardiac mortality and dangerous heart rhythms (arrhythmias).
Arrhythmia and Electrophysiology also note that general-population IVCD is strongly associated with an elevated risk of cardiac events.