Scleroderma Unmasked by Dyspnea, NSVT, and a Trifascicular Conduction Block

A 57-year-old male with chronic bilateral lower extremity edema of two to three years' duration and known lymphedema presented to the emergency department with worsening dyspnea and progressive activity intolerance over the prior two to three months. His past medical history included CKD stage 4 and hypertension, with a recent hospitalization for hypertensive urgency managed with diuresis and medication adjustment. He also reported a subjective 30-pound weight loss over the preceding three months and a recent fall while showering, attributed to dizziness.

The initial clinical impression was acute HFrEF exacerbation, but transthoracic echocardiography (TTE) revealed only low-normal LV systolic function with an EF of 50–55% and normal right ventricular size and function — far less impairment than the severely elevated biomarkers suggested. Physical examination revealed an unexpected finding: dactylitis, telangiectasias, and Raynaud phenomenon on examination of the hands. Serologic workup returned positive antinuclear antibodies (ANA) and scleroderma-specific SCL-70 antibodies, confirming the clinical suspicion for systemic sclerosis (SSc).

High-resolution CT chest was performed given the significant dyspnea and showed nonspecific ground-glass opacities, raising concern for early interstitial lung involvement.

Figure 1

HRCT Chest: Ground-Glass Opacities, Left Middle Lobe

Mild ground-glass opacities in the left middle lobe without honeycombing represent early interstitial lung involvement in systemic sclerosis. In SSc, interstitial lung disease (ILD) is the leading cause of death, typically manifesting as nonspecific interstitial pneumonia (NSIP) pattern. The absence of honeycombing suggests early-stage disease where treatment may still meaningfully alter progression.

Figure 2

HRCT Chest: Bilateral Ground-Glass Opacities, Middle Lobes

Bilateral middle lobe ground-glass opacities confirm symmetric pulmonary involvement. In the context of SSc with positive SCL-70 antibodies (anti-topoisomerase I), the risk of significant ILD is substantially elevated — SCL-70 positivity is strongly associated with diffuse cutaneous SSc and a more aggressive pulmonary course compared to anti-centromere antibody-positive limited disease.

Figure 3

HRCT Chest: Bilateral Ground-Glass Opacities, Lower Lobes

Lower lobe involvement with a basal predominance pattern is the classic distribution for SSc-ILD, reflecting the NSIP pattern. The extension from middle to lower lobes visible across serial CT images documents the pulmonary distribution and informs staging. Serial HRCT and pulmonary function testing with DLCO should follow to track disease trajectory.

During admission, the patient developed runs of nonsustained ventricular tachycardia (NSVT) on telemetry with associated palpitations. Serial ECGs demonstrated a prolonged PR interval, incomplete left anterior fascicular block (LAFB), and incomplete right bundle branch block (RBBB) — a combination suggesting multifascicular conduction disease attributable to myocardial fibrosis from SSc.

Figure 4

ECG: Prolonged PR Interval, Incomplete RBBB, and Incomplete LAFB

This ECG demonstrates the hallmarks of scleroderma cardiac involvement: a prolonged PR interval reflecting AV nodal fibrosis, incomplete RBBB as the most common SSc-associated conduction abnormality, and incomplete LAFB indicating involvement of the left anterior fascicle. This trifascicular pattern has specific prognostic implications — Follansbee et al. showed that RBBB and isolated LAFB are associated with preserved EF, while progression to bifascicular block (RBBB + LAFB) predicts future LV systolic dysfunction.

Cardiology and electrophysiology were consulted for inpatient management of the new-onset arrhythmias. The patient's dyspnea and dizziness improved significantly with IV furosemide diuresis over several days, and he was transitioned to oral furosemide, metoprolol, nifedipine XR (for Raynaud), and losartan (continued for renoprotection per nephrology). Prednisone was deliberately withheld to prevent precipitation of sclerodermal renal crisis. He was discharged in improved, medically stable condition with referrals to rheumatology, pulmonology, cardiology, and electrophysiology.

Discussion

Systemic sclerosis is fundamentally a disease of fibrosis and vasculopathy — and the heart is not exempt. Primary cardiac involvement in SSc operates through a cascade beginning with recurrent microvascular ischemia: repetitive episodes of coronary microvessel vasospasm (analogous to cutaneous Raynaud phenomenon in the heart) lead to ischemic necrosis, reperfusion injury, and ultimately myocardial fibrosis. This fibrotic infiltration disrupts the electrical architecture of the myocardium, particularly the conduction system, resulting in the full spectrum of arrhythmias and conduction delays seen in this patient. The paradox of this case is that a profoundly elevated NT-proBNP (12,086 pg/mL) coexisted with a preserved-to-low-normal LVEF on echocardiography — a dissociation that should trigger consideration of infiltrative or restrictive cardiomyopathy rather than straightforward systolic heart failure.

Prognosis tracking the conduction pattern is clinically actionable. Follansbee et al.'s seminal work distinguished arrhythmias associated with preserved EF (RBBB, isolated LAFB) from those associated with abnormal LV function (LBBB, bifascicular block). This patient's current pattern — RBBB plus incomplete LAFB — represents the pre-bifascicular state, and progression to complete RBBB + complete LAFB would signal impending LV systolic deterioration and potential HFrEF. Arrhythmia-related mortality accounts for approximately 6% of SSc deaths, underscoring the importance of early electrophysiology evaluation, serial ECG and Holter monitoring, and low threshold for ICD consideration in patients who progress to complete bifascicular block or symptomatic NSVT.