What are the possible complications of a cardiomyopathy?
The severity of symptoms and the risk of complications vary greatly from patient to patient. Many patients do not experience significant symptoms for many years. Each patient with CM must be individually evaluated and counseled to prevent and manage complications.
The course of symptoms
Generally the type of symptoms, both mild and severe, tends to be stable, but they may increase over time, depending on the type of disease.
Pharmacological and non-pharmacological therapies can control symptoms and prevent their progression. In some patients, for example with dilated cardiomyopathy (DCM), dilation and reduced contractile force can even lead to a return to normal with available therapies. Conversely, a minority of patients may experience slow or even sudden worsening. It is always necessary to undergo periodic check-ups and promptly report any new symptoms to a cardiologist, particularly dizziness or loss of consciousness (syncope) and reduced exercise capacity.
Arrhythmias
Arrhythmias, or cardiac irregularities, are a common complication. They can be felt as palpitations and discovered with an ECG, during stress testing, or with a dynamic ECG. Some arrhythmias (e.g., ventricular tachycardia or atrial fibrillation) are serious and require specific treatment.
Atrial fibrillation or flutter (AF)
This arrhythmia, which originates in the atrium, usually presents with a very rapid heartbeat (e.g. 150 beats per minute), which can cause chest pain (angina) or even acute heart failure (pulmonary edema) in patients with CM. It can be occasional and cease spontaneously after a few minutes or many hours (paroxysmal atrial fibrillation). It is frequent in patients with dilated atrium or atria and in advanced age. To prevent AF, antiarrhythmic drugs are indicated, or electrical cardioversion to restore normal rhythm. If it recurs, ablation may be useful.
Ventricular Tachycardia (VT)
These arrhythmias, which can appear suddenly and last for a long time (sustained VT), are threatening. They can cease spontaneously, perhaps after causing loss of consciousness (syncope), or degenerate into a worse arrhythmia, “ventricular fibrillation,” which leads to cardiac arrest if not promptly interrupted by an external defibrillator (AED) or an ICD.
It is favored by reduced levels of potassium in the blood, which must always be higher than 4 mEq/l
Non-sustained VT episodes (NSVT lasting less than 30 seconds) are frequently detected with dynamic ECG. These are only one indicator of a higher risk of cardiac arrest.
Cardiac Arrest (AC) and Sudden Death (MI)
Only a minority of patients experience cardiac arrest, which, if not resuscitated, leads to sudden death (SD). It is more common in young patients and in those with heart failure. Young age, along with other factors, such as the presence of life-threatening arrhythmias (NSVT or VT), ventricular aneurysms, or a young SD (before age 50) in a family member, may indicate the need for ICD implantation to prevent this disastrous event. The arrest may be preceded by a few symptoms, the most important of which is sudden loss of consciousness (“syncope”), but often there are no warnings.
Assessing individual risk for AC and MI is not easy. There are systems, albeit imprecise, for calculating risk, but due to its complexity, the assessment must be performed by an experienced cardiologist.
Sinoatrial (BSA) or atrioventricular (BAV) block
Rarely, the normal electrical signal may not be emitted regularly (SAB) or its transmission from the atria to the ventricles may be slowed or blocked (AV block). This can cause a slow heart rhythm (second or third degree AV block) and in these cases it may be necessary to implant a “pacemaker” (PM), a cardiac stimulator, under the skin, to restore normal emission or transmission of the signal from the atria to the ventricles.
Heart failure
This is the most common complication in patients with CM. However, with some exceptions, it usually appears many years after diagnosis. Fortunately, there are now numerous therapies that can resolve or improve heart failure. In obstructive HCM, for example, it can be resolved by eliminating the obstruction with septal reduction via myectomy and/or mitral valve replacement, or by alcoholizing the septum. In HCM with wide left bundle branch block, it can be resolved with the implantation of a PM with biventricular pacing that leads to cardiac resynchronization (CRT).
Intracavitary thrombosis (atrial or ventricular) and cerebral ("stroke") or peripheral embolism
During AF, “thrombi” can form in the left atrium, and these can be transported by the blood flow (“embolism”) or into a cerebral artery and cause cerebral ischemia (“stroke”) or into a peripheral artery. More rarely, the thrombus can localize in the LV, especially if this is very dilated or if an “apical aneurysm” has developed. In all these cases, and in relation to age and atrial dilation in the presence of AF, it is recommended to take anticoagulant therapy (oral or with subcutaneous heparin injections) to avoid or try to dissolve the “thrombus”.
Endocarditis
It is a bacterial infection of a heart valve or a foreign device such as a PM or ICD with their "stimulating" electrodes inserted into the veins, or a S-ICD inserted under the skin. It occurs very rarely, especially if the valve is already damaged or intravenous injections are administered in conditions of poor hygiene (e.g., heroin or other drugs). It manifests itself with episodes of continuous fever, even high fever. The bacteria can be identified and "cured" with appropriate antibiotic therapy. It is also important to prevent it with antibiotic prophylaxis during major surgical procedures. In some cases, it may be necessary to replace the valve or proceed to remove the PM/ICD and/or the infected electrode or S-ICD.
