Are dilated cardiomyopathy and eccentric hypertrophy (left ventricular hypertrophy) the same condition?

From the Guidelines

Dilated cardiomyopathy and eccentric hypertrophy are distinct entities, with dilated cardiomyopathy being a specific disease state characterized by weakened heart muscle and impaired pumping function, whereas eccentric hypertrophy is a structural change in the heart that can be physiological or pathological, but does not necessarily imply impaired cardiac function.

Key Differences

• Eccentric hypertrophy is characterized by an increase in chamber size with relatively normal wall thickness, resulting from volume overload, as noted in a study published in the European Heart Journal 1.
• Dilated cardiomyopathy, on the other hand, is defined as a heart muscle disease characterized by left ventricular dilatation and global or regional systolic dysfunction, not attributable to abnormal loading conditions, according to a systematic review published in the European Heart Journal 1.

Clinical Implications

• The distinction between dilated cardiomyopathy and eccentric hypertrophy matters clinically because treatment approaches differ significantly, with dilated cardiomyopathy typically requiring heart failure medications and potentially devices like ICDs, while management of eccentric hypertrophy depends on addressing the underlying cause, as discussed in a study published in Circulation Research 1.
• Dilated cardiomyopathy often involves significant systolic dysfunction and can lead to heart failure, whereas eccentric hypertrophy may exist with preserved cardiac function, highlighting the importance of accurate diagnosis and management, as emphasized in a review published in the European Heart Journal 1.

Diagnosis and Management

• The therapeutic management of dilated cardiomyopathy has traditionally overlapped with heart failure treatment, sharing primary therapeutic options, from optimal decongestion to appropriate risk stratification for arrhythmias, as noted in a systematic review published in the European Heart Journal 1.
• Advances in the field of cardiogenetics and the impact of deep phenotyping through advanced imaging have introduced a new diagnostic perspective and have contributed to the detection of subclinical forms of disease, as discussed in a study published in the European Heart Journal 1.

From the Research

Definition and Characteristics

• Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular dilatation and contractile dysfunction 2.
• Eccentric hypertrophy is a type of hypertrophy caused by cell elongation, which can lead to dilatation and is associated with an especially poor prognosis 3.

Relationship between DCM and Eccentric Hypertrophy

• Eccentric hypertrophy tends to progress and is associated with dilatation, which is a characteristic of DCM 3.
• DCM can result from various pathologies, including genetic and acquired causes, and can present with similar characteristics to eccentric hypertrophy, such as left ventricular dilatation and contractile dysfunction 4, 2.

Key Differences

• While eccentric hypertrophy is a type of hypertrophic response to overload, DCM is a specific cardiac diagnosis characterized by left ventricular dilatation and contractile dysfunction 3, 2.
• The prognosis and treatment of DCM and eccentric hypertrophy may differ, with DCM often requiring management of heart failure and eccentric hypertrophy potentially being addressed through inhibition of maladaptive features of overload-induced proliferative signaling 3, 2.

Treatment and Management

• Treatment of DCM typically involves medications that improve survival and reduce hospital admission, such as angiotensin-converting enzyme inhibitors and β blockers 2.
• ACE inhibitors have been shown to improve coronary flow reserve in DCM by a bradykinin-mediated, nitric oxide-dependent mechanism 5.