Introduction
Persistence or recurrence of symptoms early after septal reduction by
surgical septal myectomy or alcohol septal ablation (ASA) is most often
due to residual or recurrent left ventricular outflow tract
obstruction.[1,2]
After obtaining written consent from the patient, we describe in the
present report that the patient had persistent exertional dyspnea for
six months following ASA and was found to have multiple potential
cardiac causes for her disability.
Patient presentation and management
A 71-year-old woman with the previous diagnosis of obstructive HCM
presented to our Clinic with complaints of exertional breathlessness and
chest fullness for three years. Because of progressive symptoms that
were not relieved with medical therapy, she underwent ASA at another
institution. Complete heart block complicated her post-ablation course,
and she received a dual-chamber transvenous pacemaker-defibrillator.
Post procedure, she continued to experience persistent limiting symptoms
of exertional shortness of breath and chest fullness.
There were several important findings on her clinical examination. She
had severe systemic hypertension with blood pressure of 180/90 mmHg. Her
jugular venous pressure was markedly elevated with rapid X and Y
descents. She had a 2/6 systolic ejection murmur at the left sternal
border which increased from the squat to stand position.
Transthoracic echocardiography
demonstrated septal hypertrophy and systolic anterior motion of the
mitral valve producing severe left ventricular outflow tract (LVOT)
obstruction with a peak Doppler gradient of 77 mmHg. There was, in
addition, midventricular obstruction with gradient of 31 mmHg. Extensive
calcified plaques in the ascending aorta and aortic arch were seen on CT
angiography (Figure 1 ). Cardiac catheterization demonstrated a
large gradient between the LV apex and aorta from combined
midventricular and subaortic left ventricular outflow obstruction. The
gradient decreased during inspiration (Figure 2A ) with a
Brockenborough response after a PVC (Figure 2B ), indicating a
dynamic outflow obstruction. There was also elevation and
end-equalization of diastolic pressures in all four cardiac chambers to
25 mmHg, and the cardiac index was reduced to
2.3L/min/M2; she had evidence of enhanced ventricular
interaction all consistent with the diagnosis of constrictive
pericarditis (Figure 2C) . Additional medical problems included
systemic hypertension, diabetes, obesity (BMI > 37kg/m2),
paroxysmal atrial fibrillation, and chronic obstructive pulmonary
disease.
At operation, the pericardium was found to be thickened and intensely
constrictive. Further, severe calcification of the proximal aorta
prevented an adequate aortotomy for myectomy. Prior to bypass, the
gradient from the left ventricle to the aorta was 80 mm Hg at rest, and
this increased to 143 mm Hg following a premature ventricular
contraction (PVC). After myectomy, the gradient was 7 mm Hg at rest and
20 mm Hg following PVC.
After cannulating the proximal aortic arch for arterial inflow, a
two-stage cannula was placed in the right atrium. During the initial
phase of bypass, a complete pericardiectomy was performed including the
anterior portion and the diaphragmatic pericardium. The aorta was
cross-clamped, and the calcified midportion of the ascending aorta was
excised. We then performed an extended transaortic septal myectomy. A
22-mm Hemashield replacement graft was trimmed to the correct length and
sewed to the proximal and distal ends of the aorta. The apex of the
heart was elevated into the wound, and through an apical ventriculotomy,
we performed an extensive midventricular septal myectomy. The apical
ventriculotomy was closed with felt strip reinforcement. Hemodynamics
was satisfactory following cardiopulmonary bypass, and intraoperative
transesophageal echocardiography demonstrated a good result from
myectomy with no residual systolic anterior motion of the mitral valve
and a maximum intraventricular gradient of 14 mmHg. Postoperative
pathology confirmed a non-calcified fibrous thickening (up to 1 cm) and
non-granulomatous lymphoplasmacytic infiltration of the pericardium. On
postoperative TTE, left ventricular ejection fraction was 67% and there
was no systolic anterior motion of the mitral valve or residual
subaortic obstruction. She was dismissed home from the hospital 7 days
after operation. At the time of last follow-up three years
postoperatively the patient was well and free of cardiac symptoms.