Case History
A 78-year-old Caucasian male with a past medical history significant for
chronic diastolic heart failure with preserved ejection fraction
(HfpEF), atrial fibrillation status post pulmonary vein isolation 8
years ago and extensive circumferential ablation for recurrent atrial
fibrillation 6 years ago, as well as cavo-isthmus ablation with
bidirectional block for atypical atrial flutter with recurrence of
atrial flutter 5 years ago presented with increasing dyspnea and
palpitations. Flecainide and Diltiazem had been discontinued due to side
effects and renal impairment.
There was discordance between QRS voltage on ECG and the degree of left
ventricular (LV) wall thickness on echocardiogram (Figure 1B, 1C, 1D),
leading to suspicion for. infiltrative cardiomyopathy, subsequently
confirmed as Transthyretin type type cardiac amyloidosis and confirmed
on two-dimensional speckle-tracking echocardiography (2D-STE) and
cardiac magnetic resonance imaging (MRI). Serum light chains were both
slightly elevated but with normal ratio. STE revealed abnormal global
averaged LV longitudinal peak systolic strain of -8 % (normal = more
negative than -18%, Figure 2A), and prominent apical sparing pattern
suggestive of cardiac amyloidosis (Figure 2B). MRI showed significantly
increased left ventricular wall thickness, diffuse subendocardial,
predominantly late, gadolinium enhancement and preserved LV function,
ejection fraction of 59% and normal LV volumes. Right ventricular (RV)
volumes were preserved with mild systolic dysfunction and RV ejection
fraction of 41%. Late gadolinium enhanced sequences demonstrated global
predominantly subendocardial but some areas of transmural late
gadolinium enhancement Enhancement also extended to the atrial walls,
left greater than right, with mild thickening of the interatrial septum
(Figure 2C). Pre-contrast T1 mapping value was significantly elevated at
greater than 1300 ms (normal 1020 ms, Figure 2D). Findings were
consistent with cardiac amyloidosis. Patient was started on Tafamadis,
underwent transesophageal echocardiography (TEE) guided cardioversion
and was discharged.
Two months later patient was admitted for recurrent progressive
exertional dyspnea and palpitations with ECG similar to prior admission
2 months ago showing atypical slow atrial flutter with 2:1 block and
left bundle branch block (Figure 1A). Heart rate was 90 beats/minute
and blood pressure was 120/86 mm Hg. Chest x-ray did not show any acute
cardiopulmonary process. INR was 2.0, serum potassium was 5.3 mEq/L,
serum creatinine was 1.76 mg/dL, serum magnesium was 2.4 mg/dL, and
NT-Pro BNP was 4335 pg/mL (normal ≤ 77). Medications included apixaban 5
mg bid, spironolactone 25 mg qd, tafamidis 61 mg qd and tramadol 50 mg
qd. He was initiated on amiodarone 100 mg bid and furosemide diuresis
and referred for TEE-guided cardioversion. TEE identified no left or
right atrial appendage thrombus, mild MR and trace TR. TEE probe was
left in situ during cardioversion to assess left atrial (LA) appendage
post cardioversion, due to post cardioversion atrial stunning, and
higher risk of thrombus formation in cardiac amyloid. Patient was
successfully cardioverted at first attempt with return to normal sinus
rhythm (Figure 3). TEE demonstrated LVEF of 38% prior to, and 41%
following cardioversion. Pre-cardioversion TEE pulsed wave PW Doppler
(PW) of the right atrial appendage showed regular Doppler velocities
corresponding to each flutter wave on the ECG but with reduced amplitude
of every alternate appendage velocity (Figure 4A). Doppler velocity
returned to normal pattern post-cardioversion (Figure 4B). RA appendage
velocities were normal in amplitude post cardioversion. LA appendage
flow velocities showed similar pattern with alternate smaller amplitude
PW Doppler velocities corresponding to every alternate flutter wave
(Figure 4C), with return to normal pattern but with reduced velocities
post-cardioversion (Figure 4D). Mitral inflow PW Doppler showed a single
early filling wave with an indiscernible A wave pre cardioversion
(Figure 4E). which reverted to E and A fusion pattern post cardioversion
due to the presence of first-degree AV block (Figure 4F). Tricuspid
annular tissue Doppler imaging pre cardioversion showed two additional
velocities, one with smaller amplitude preceding and one with larger
amplitude following annular e’ wave, both immediately following the
flutter P wave on the ECG prior to cardioversion (Figure 5A). These
waves disappeared during sinus rhythm with good amplitude tissue Doppler
a’ wave suggesting good right atrial function after cardioversion
(Figure 5B). These velocities were almost unrecognizable on mitral
inferolateral annular Doppler pre cardioversion (Figure 5C) and normal
tissue Doppler mitral annular pattern emergent post cardioversion
(Figure 5D).
Other pre cardioversion TEE findings included restrictive appearing
mitral inflow pattern (Figure 5E) and increased TR peak velocity at 3.1
m/sec corresponding to a pressure gradient of 38 mm Hg and consistent
with LV diastolic dysfunction and pulmonary venous hypertension. He
remained in normal sinus rhythm and discharged the following day. Five
months later, the patient underwent dual-chamber biventricular pacemaker
implantation with the coronary sinus lead placed into a lateral branch
of the coronary sinus. He underwent AV nodal ablation three months
after the implantation of the pacemaker. ECG post AV nodal ablation
showed biventricular pacing at 70 bpm with underlying slow atrial
flutter (Figure 6).