You are asked to see a 44-year-old African-American female after a recent episode of frank syncope. On interview she relates a history of palpitations, near syncope, and three episodes of frank syncope over the past two years. An echocardiogram, performed about two weeks after her first syncopal event, revealed trace MR, a LVEF of 50-55% and PA systolic pressures of 25-30mmHg. A myocardial perfusion study showed no inducible ischemia and an EF of > 60%. An ECG was purportedly normal; no cardiac monitoring was performed at that time.
She was diagnosed with systemic lupus erythematosus (SLE) in her mid-20s. She has had several flares involving the thyroid, skeletal muscles and kidneys. Although your review of her records does not find a specific diagnosis of myocarditis, her cardiac function can be compromised during these more acute phases of her illness. She was hospitalized two months prior to today's visit with a SLE flare associated with NYHA class III CHF symptoms including orthopnea and dyspnea provoked by ambulation. Prior to admission she had noted palpitations, tachycardia and near syncope, but no frank syncope. Telemetry monitoring during this hospitalization detected nonsustained ventricular tachycardia of up to 15 beats, but no sustained atrial or ventricular arrhythmias. AV conduction was normal, with a PR interval of 155ms. An echocardiogram while hospitalized showed an EF of 20-25% in a globally hypokinetic pattern, but with no overt valvular abnormalities. CHF medical therapy including carvedilol, telmisartan, spironolactone, furosemide and digoxin was begun. Her SLE flare was treated with IVIG and intravenous steroids as an inpatient and with hydroxychloroquine and oral steroids at discharge.
Two weeks post discharge she underwent a cardiac magnetic resonance imaging (CMR) with gadolinium: normal diastolic and systolic function with an LVEF of 54% were seen. Some mild intensity delayed gadolinium enhancement was noted at the LV apex.
Her CHF symptoms have improved to NYHA class II - she easily tolerates ambulation but more strenuous exertion causes dyspnea. She is compliant with all CHF medical therapy initiated while hospitalized. Despite this she suffered yet another syncopal event a few days prior to your assessment. She describes her event as a brief sensation of palpitations followed by an abrupt loss of consciousness. She denies nausea, diaphoresis or a gradual development of malaise. She is able tolerate standing for prolonged periods without provocation of near syncope. An echocardiogram in your office shows mild systolic dysfunction with LVEF of 45-50% but is otherwise unremarkable. ECG shows sinus rhythm at 68bpm with PR 162ms, QRS 76ms and QTc 402ms. No overt conduction, ST or T segment abnormalities are present.
During your discussion with the patient, you recommend:
The correct answer is: C. an electrophysiology study followed by ICD implantation if VT or VF is inducible or ILR placement if non-inducible
This patient has a waxing and waning cardiomyopathy in the setting of SLE, and recurrent episodes of syncope that appear consistent with an arrhythmic etiology. Although some nonsustained ventricular arrhythmia has been observed on telemetry, there has not been correlation of arrhythmia with her symptoms of near syncope/syncope. Her syncopal events have occurred both when her LVEF is depressed and when essentially normal. Although her LVEF depression and CHF symptoms have previously been severe enough to potentially warrant primary prevention ICD placement1, they do not do so currently.
Autoimmune disease patients that have cardiac involvement are at risk for accelerated atherosclerosis, conduction system abnormalities and ectopy/arrhythmia, including SVT and VT2. For adult SLE patients, complete heart block is exceedingly rare (11 case reports as of 2006)3. This patient has had no evidence of conduction abnormalities, even when hospitalized. Ventricular arrhythmia in adult SLE patients is infrequent, but sudden death has been reported as a significant cause of mortality in one observational study4. A better understanding of this patient's risk of cardiac arrest seems important in light of her recurrent syncope, NSVT on telemetry, and transient declines in LVEF with associated CHF symptoms.
Tilt table testing (A) did not seem adequate as it does not address the question of whether her syncopal events could be caused by ventricular arrhythmia and thus aid in risk stratification for cardiac arrest. Had tilt table testing been performed and syncope induced, it would be difficult to assume that neurally mediated syncope was the sole etiology of her syncope. In addition, her symptoms were more suggestive of an abrupt onset of arrhythmia.
Noninvasive monitoring by either Holter or MCOT (B) are of too brief a duration to provide a reasonable probability of correlating an arrhythmia with syncope. She has had syncope a total of 3 times in 2 years - MCOT is typically for 30 days or less. If near syncope were correlated with nonsustained VT (a possible scenario) then (C) or (D) would probably be considered. Consequently this option seems to be "asking the right question" but perhaps not for a long enough period of time nor with the right tools.
ICD implantation (D) may appear reasonable from a clinical standpoint, and had her evaluation been performed at a time when her CHF symptoms and LVEF met primary prevention ICD criteria this would probably be the best course of action. Although her LVEF has recovered, ventricular arrhythmia represents the most probable cause of her syncope and future episodes of LV dysfunction seem likely. Thus her recurrent syncope in the setting of transient LV dysfunction associated with CHF symptoms could be argued as justification for ICD placement. However, the current ACC/AHA/HRS device therapy guidelines state that unexplained syncope in the absence of structural heart disease or inducible ventricular arrhythmia is to be avoided5. Clinical scenarios with waxing and waning LVEFs and high risk features such as recurrent syncope are not explicitly covered in current practice guidelines. From a practical standpoint, obtaining payor preauthorization for ICD implantation might prove difficult without a clear correlation between her arrhythmia and her syncope.
After a discussion of the risks and potential benefits we proceeded to (C) - an EP study, with plans for ICD implantation if inducible for ventricular tachycardia or ventricular fibrillation, and for loop recorder placement otherwise. Although the value of an EP study in adult SLE patients is unproven, one proposed treatment algorithm suggests that this is reasonable2.
She was inducible for sustained polymorphic ventricular tachycardia and received a dual chamber ICD. Since implantation (approximately 22 months ago) she has had no further syncopal events, has received no ICD therapy and has had no VT or VF episodes recorded by her ICD. AV conduction remains normal with no detectable ventricular pacing.
Bardy GH, Lee KL, et al.; Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) Investigators. Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med 2005; 352:225-37.
Seferovic PM, Risitc AD, et al.; Cardiac arrhythmias and conduction disturbances in autoimmune rheumatic diseases. Rheumatology 2006; 45:iv39-42.
Lazzerini PE, Capecchi PL, et al,; Connective tissue diseases and cardiac rhythm disorders: An overview. Autoimmunity Reviews 2006; 5; 306-313.
Abu-Shakra M, Urowitz MB, et al.; Mortality studies in systemic lupus erythematosus. Results from a single center. I. Causes of death. J Rheumatology 1995; 22:1259-1264.
Epsten, AE, DiMarco JP, et al,; ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. Heart Rhythm 2008; 5:e1-62.