The Heart-SCC Puzzle

Systemic Sclerosis (SSc) is a complex systemic illness that is characterized by a heterogeneous mix of serious and sometimes life-threatening clinical manifestations. Because of the extensive involvement of internal organs (e.g., lung, heart, kidney, gastrointestinal system), patient care requires a comprehensive approach and a solid preparation to manage the clinical picture. Of manifestations in SSc, cardiac involvement is often clinically silent or occult and, indeed, may be missed without special study. The main signs and symptoms, however, are usually related to cardiomyopathy, pericarditis, conduction and rhythm disturbances, or vascular disorders.¹ The impact of the cardiac disease on morbidity and mortality in SSc makes understanding of this manifestation a top priority for the rheumatologist caring for patients with this disease.

In the clinic, the evaluation of heart involvement in SSc can be difficult, since a variable pattern of symptoms like dyspnoea upon exertion, palpitations, dizziness, atypical chest pain, and syncope may occur. These features may overlap with other problems in SSc (e.g., lung disease) creating a dangerous “puzzle” associated with increased mortality—one that may challenge the physician’s skills. In addition to primary heart involvement, pulmonary hypertension and renal involvement can induce a secondary cardiac disease and dysfunction that are a harbinger of poor prognosis. By diagnosing heart involvement in SSc early in its course, timely and effective treatment measures can be ini­­tiated, optimizing the clinical outcome. Here we focus on the diagnosis of the different “puzzle” components of heart involvement in SSc as well as the available treatment.

Electric Piece of the Puzzle

Conduction defects and arrhythmias occur frequently in SSc as a result of fibrosis or ischemia of the conduction system. Arrhythmias may be a manifestation of early cardiac involvement and may be detected during ambulatory monitoring.² Palpitations or syncope may occur, but usually patients are asymptomatic. Ventricular arrhythmias and sudden cardiac death are the most serious and dreaded complications. Pathological studies have shown diffuse patchy myocardial fibrosis that may favor ventricular arrhythmias by a re-entry mechanism or by activity of trigger areas. Another arrythmogenic substrate results from small (millimeter) ischemic areas (contraction band necrosis) created by repeated abnormal vasospasm of small coronary arteries and arterioles mimicking Raynaud’s phenomenon of the myocardium.³

The most frequent conduction abnormalities in SSc are P-R interval prolongation (first-degree heart block), left anterior fascicular block, right and left bundle branch block, and nonspecific intraventricular conduction defects. With the same pathophysiological substrate, the most common arrhythmias occurring in SSc are premature ventricular contractions in the form of couplets multifocal, premature atrial contractions, and supraventricular tachycardia. Particular attention must be directed to sustained ventricular tachycardia that represents a poor prognostic factor for sudden death.