Saif Al-Najafi MD, Daniel Alexander DO, Zain AL Zahrani MD
Winchester Medical Center/Valley Health. Winchester, Virginia
Clinical History
A 58-year-old male with biopsy-proven pulmonary sarcoidosis presented to the emergency department with intermittent chest discomfort for a few days. An electrocardiogram (ECG) (Figure 1) on admission demonstrated normal sinus rhythm with first-degree atrioventricular (AV) block and right bundle branch block (RBBB), unchanged from an ECG performed two weeks earlier. Initial blood tests, including cardiac markers, were unremarkable. Ischemic workup, including a stress test, was normal.
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| Figure 1. ECG showing normal sinus rhythm, first degree heart block, RBBB and left anterior fascicular block |
During hospitalization, telemetry revealed intermittent high-grade AV block and 2:1 AV conduction and complete heart block (Figure 2 and 3). The patient remained asymptomatic, without syncope, presyncope, dyspnea, or hemodynamic instability.
He recalled a recent tick bite, and screening revealed positive Lyme serology (IgM and IgG).
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| Figure 2. Telemetry strip showing 2:1 second degree heart block |
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| Figure 3. Telemetry strip showing intermittent complete heart block |
Given the recent tick exposure and positive serology, the initial presumption was Lyme carditis, and the patient was started on intravenous ceftriaxone. However, after seven days of appropriate antibiotic therapy, the high-grade AV block persisted. Throughout hospitalization, the patient continued to exhibit high-grade AV block with bradycardia, requiring continuous monitoring.[1] In view of the persistent conduction disease and the patient’s recent diagnosis of pulmonary sarcoidosis, cardiology was consulted, and cardiovascular magnetic resonance (CMR) was ordered to further evaluate for infiltrative cardiomyopathy.
CMR Findings
CMR (1.5T Aera (Siemens Healthineers, Erlangen Germany)) demonstrated a normal left ventricular (LV) cavity size with moderate to severe regional wall thickening, involving the basal anterior wall (18 mm), basal septum (18 mm), and inferior wall (16 mm), with relative thinning of the mid-to-apical anterior wall. There was severe hypokinesis to akinesis of the apical segments (Movie 1), with a left ventricular ejection fraction (LVEF) of 52%.
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| Movie 1. Four chamber balanced steady state free precession (bSSFP) cine showing hypokinesis to akinesis of apical segments. |
Native T1 myocardial mapping showed globally prolonged relaxation times, indicating myocardial fibrosis, ranged between 1107 to 1196 ms (normal values at our hospital 970 – 1000 ms). T2 myocardial mapping showed globally prolonged relaxation times, indicating active myocardial inflammation, ranged between 51 – 64 ms (normal values at our hospital 42-48 ms).
Late gadolinium enhancement (LGE) imaging revealed extensive multifocal myocardial involvement with subepicardial, mid-wall, and transmural enhancement in a non-coronary distribution at the the basal anterior and inferior walls, basal to mid anteroseptum, the apical inferior wall, the apical cap, the right ventricular (RV) myocardium and right ventricular outflow tract (RVOT) (Figures 4-6). The RV was normal in size and systolic function. The left atrium was mildly dilated, with mild mitral regurgitation. Known mediastinal and peribronchial lymphadenopathy was present.
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| Figure 4. Delayed post gadolinium images (Phase Sensitive Inversion Recovery (PSIR)) in a short axis stack showing extensive multifocal myocardial involvement with subepicardial, mid-wall, and transmural enhancement at the basal anterior and inferior walls, basal to mid anteroseptum, the apical inferior wall and true apex, RV myocardium and RVOT. |
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| Figure 5. Delayed post gadolinium images (PSIR) in a two chamber view showing subepicardial and transmural enhancement of the basal inferior and anterior walls in addition to the apical inferior wall. |
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| Figure 6. Delayed post gadolinium images (PSIR) in a four chamber view showing transmural enhancement at the apical septal wall. |
Conclusion
The CMR findings were highly consistent with cardiac sarcoidosis. The combination of multifocal non-ischemic LGE, septal infiltration, and RV involvement in a patient with biopsy-proven extracardiac sarcoidosis strongly supported this diagnosis. These imaging findings are consistent with patterns described in the American Heart Association (AHA) scientific statement on cardiac sarcoidosis.[2] While no LGE pattern is pathognomonic, its presence in conjunction with systemic sarcoidosis and conduction abnormalities strongly supports a diagnosis of cardiac sarcoidosis. This patient met multiple major criteria from both Heart Rhythm Society (HRS) and Japanese Circulation Society (JCS) guidelines, including: biopsy-proven pulmonary sarcoidosis, high-degree AV block, multifocal LGE on CMR, and LV systolic dysfunction, confirming the diagnosis of cardiac sarcoidosis even in the absence of myocardial biopsy.[3]
Although Lyme carditis can cause myocarditis and high-degree AV block, it is typically transient and rapidly reversible with appropriate antibiotic therapy. In a large clinical series, high-degree AV block due to Lyme carditis resolved within one week of initiating antibiotics in the majority of patients.[1] In the present case, the patient continued to demonstrate persistent high-grade AV block and bradycardia throughout hospitalization, despite 7 days of intravenous ceftriaxone, making Lyme carditis an unlikely sole etiology.
Given the extensive myocardial scar and conduction system involvement, the patient underwent pacemaker / implanted cardiodefibrillator (ICD) implantation. High-dose immunosuppression was deferred because of active Lyme infection, with a plan for fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging following completion of antibiotic therapy to assess inflammatory activity and guide sarcoidosis-directed treatment.
Perspective
Cardiac sarcoidosis is a potentially life-threatening manifestation of systemic sarcoidosis and frequently presents with AV block, ventricular arrhythmias, and cardiomyopathy.[4] CMR is a high-spatial-resolution modality that allows detection and localization of myocardial LGE, reflecting fibrosis or inflammation. Typical CMR findings in cardiac sarcoidosis include: subepicardial or mid-wall LGE, often multifocal, involving the LV septum, LV free wall, and RV free wall in a non-coronary distribution of LGE. Moreover, there is a well established association with conduction abnormalities or arrhythmias, even if LVEF is preserved.
Aside from Lyme carditis, other potential differential diagnoses include cardiac amyloidosis, Fabry’s disease and viral myocarditis. Cardiac amyloidosis, although having globally prolonged relaxation time on the native T1 myocardial mapping, it would likely have more prolonged values (>1300 ms), reversed nulling pattern of the TI scout sequence and more diffuse myocardial enhancement.[5] As for Fabry’s disease, the native T1 myocardial mapping would show low values. Although the patient does meet the modified Lake Louise criteria for myocarditis, the clinical presentation and the presence of pulmonary sarcoidosis make cardiac sarcoidosis a much more likely diagnosis. This case also demonstrates, despite a relatively preserved LV systolic function, that there was extensive delayed myocardial enhancement highlighting the fact that extensive cardiac sarcoidosis and myocardial scarring could present without major functional impairment.
HRS 2014 criteria define cardiac sarcoidosis based on either histological confirmation from myocardial tissue or clinical diagnosis, which includes, histologically proven extra-cardiac sarcoidosis, cardiac manifestations such as high-degree AV block, ventricular arrhythmias, or unexplained reduced LVEF and abnormal cardiac imaging (CMR LGE or FDG PET uptake) supporting cardiac involvement.
On the other hand, the JCS 2016 criteria emphasize a combination of clinical manifestations (AV block, arrhythmias, LV dysfunction), imaging evidence (CMR LGE or FDG PET activity) and histological or clinical confirmation of extra-cardiac sarcoidosis. These features were all present in this patient, reinforcing the diagnosis of cardiac sarcoidosis in accordance with HRS and JCS criteria, and demonstrating the prognostic utility of CMR in guiding management, including ICD placement and follow-up imaging for inflammation.
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References
- Wan D, Baranchuk A. Lyme carditis and atrioventricular block. CMAJ. 2018;190(20):E622. doi:10.1503/cmaj.171452
- Cheng RK, Kittleson MM, Beavers CJ et al. Diagnosis and Management of Cardiac Sarcoidosis: A Scientific Statement From the American Heart Association. Circulation. 2024;149:e1–e26. doi:10.1161/CIR.00000000000012
- Birnie D, Ha AC, Gula LJ, Chakrabarti S, Beanlands RS, Nery P. Cardiac Sarcoidosis. Clin Chest Med. 2015 Dec;36(4):657-68. doi: 10.1016/j.ccm.2015.08.008. Epub 2015 Sep 11. PMID: 26593140
- Terasaki F, Azuma A, Anzai T, et al. JCS 2016 Guideline on Diagnosis and Treatment of Cardiac Sarcoidosis - Digest Version. Circ J. 2019 Oct 25;83(11):2329-2388. doi: 10.1253/circj.CJ-19-0508. Epub 2019 Oct 9. PMID: 31597819
- Lavall D, Vosshage NH, Geßner R, Stöbe S, Ebel S, Denecke T, Hagendorff A, Laufs U. Native T1 mapping for the diagnosis of cardiac amyloidosis in patients with left ventricular hypertrophy. Clin Res Cardiol. 2023 Mar;112(3):334-342. doi: 10.1007/s00392-022-02005-2. Epub 2022 Mar 31. PMID: 35355115; PMCID: PMC9998594
Case prepared by Anna Baritussio, MD, PhD, FEACVI
Editorial Board Member, Cases of SCMR
Department of Cardiac, Thoracic, Vascular Sciences and Public Health
Padua University Hospital, Padua, Italy