A 39 year-old male patient was admitted to our hospital to evaluate and plan the therapeutic strategy of hypertrophic obstructive cardiomyopathy that was diagnosed only a few months before. He suffered from dyspnea class III, palpitations and presyncope after a syncope in 2001. Medical treatment with verapamil led to a deterioration of his symptoms. After change to ß-blocker symptoms improved but still persisted.
The patient’s father suffered from CAD. The brother had no signs of cardiac disease at non-invasive testings. His paternal grandfather died possibly of sudden cardiac death. Genetic testing showed a mutation in MYBPC3.
At physical examination the patient had a typical 4/6 systolic murmur on 5L2 with increase at Valsalva manoeuvre.
The ECG illustrated sinus rhythm, but no severe left ventricular hypertrophy (fig. 1).
Fig. 1: ECG
Echocardiography showed asymmetric hypertrophy with septal thickness of 27 mm and posterior wall of 17 mm (fig. 2).
Fig. 2: Diastolic and systolic 4- and 3-chamber-view
The systolic function was normal whereas his diastolic function was abnormal. He had a SAM (II°-III°)- related mild to severe mitral regurgitation (fig. 3). There was not only a subaortic LVOT-obstruction but also a mid-ventricular with an intracavitary gradient of 120 mmHg at rest (fig. 3 and 4) with increase at Valsalva manoeuvre. The left atrium was already dilated with 56 mm.
Fig. 3: Midventricular and LVOT-obstruction in color Doppler and mitral regurgitatio
Fig. 4: CW-Doppler showing midventricular and LVOT obstruction
Cardiopulmonary exercise testing (bicycle test) was performed up to 106 Watts after 8 minutes. Maximal oxygen uptake (peak VO2) was reduced to 16.1 ml/kg/min (46% predicted peak VO2) (fig. 5).
Fig. 5: Cardiopulmonary exercise test VO2
Blood pressure response was normal from 120/90 mmHg to 160/80 mmHg. Holter-ECG showed sinus rhythm, parasystole, short runs of supraventricular tachycardia and non-sustained VT. The cardiac MRI showed diffuse myocardial fibrosis.
What is your therapeutic strategy?
The 39 - year old male patient suffered from symptomatic hypertrophic obstructive cardiomyopathy (IVS max. 27 mm, MYBPC3-mutation) with dyspnea class III, palpitations and an unexplained syncope in 2001. The area of LV-obstruction was midventricular to subaortic with an intracavitary gradient of 120 mmHg at rest and increase at Valsalva manoeuvre (Fig. 1 and 2). SAM-related moderate mitral regurgitation with SAM II-III was detected (Fig. 3). Left atrium was dilated with 56 mm.
Fig. 1: Diastolic and systolic 4- and 3-chamber-view echocardiography
Fig. 2: CW-Doppler showing midventricular and LVOT-obstruction
Fig. 3: Midventricular and LVOT-obstruction in colour Doppler and mitral regurgitation
As in all patients with H(O)CM therapy has to consider the two main strategies: risk stratification for the prevention of sudden cardiac death by ICD implantation and gradient reduction therapy for symptomatic improvement.
1. Risk stratification for the prevention of sudden cardiac death
According to the risk stratification model of Elliott and co-workers we identified two risk factors (unexplained exercise-induced syncope and non-sustained VT in holter-ECG) and one borderline risk factor (nearly 30mm of maximal wall thickness).1 Therefore, we assumed the patient being at increased risk for SCD. We discussed the risk model with the patient and recommended an implantation of a dual-chamber-ICD. The patient accepted and the implantation was done without complication.
2. Gradient reduction for symptomatic treatment
Therapeutic options for gradient reduction are medical treatment (in Germany betablocker and verapamil), surgical myectomy and septal ablation (PTSMA). Both drugs did not result in symptomatic and hemodynamic improvement. Furthermore, significant limitation of cardiopulmonary exercise testing with maximum oxygen uptake of 16.1 ml/kg/min was seen (Fig. 7). Therefore, we recommended gradient reduction. The different options of surgical myectomy and – due to the long intracavitary obstruction - stepwise septal ablation were discussed with the patient. The patient decided to undergo septal ablation.
As a first step subaortic obstruction should be treated. Coronary angiography showed an exclusion of CAD. There was a suitable septal perforator branch which splitted into two branches and the first perforator branch was selected. Myocardial-contrast-echo guided PTSMA was successfully performed with the injection of 2 cc alcohol in the proximal side branch of the first septal branch (Fig. 4) without complications, especially no AV-block. ECG changed to a right bundle branch block (Fig. 5). Maximum CK rise was 1372 U/l.
Fig. 4: Left coronary artery during first PTSMA with occlusion
of the proximal side branch (arrow) of the first septal perforator.
Fig. 5: ECG before (left) and after (right) septal ablation
At 3-months and 1 year follow-up the patient showed symptomatic improvement to class II. Echocardiography showed a mid-ventricular LV-obstruction of 70 mmHg at rest and 90 mmHg at Valsalva manoeuvre (Fig. 6) and only trivial mitral regurgitation. Basal septal thickness was reduced to 15 mm with persisting thickening of the mid-ventricular septum of 25 mm at maximum.
Fig. 6: Persisted obstruction in CW-Doppler
Maximal oxygen uptake in pulmonary exercise testing was increased to 20.9 ml/kg/min at 136 Watts (before septal ablation 16.1 ml/kg/min, 106 Watts, optimal exhaustion in both tests respectively) (Fig. 7).
Fig. 7: Cardiopulmonary exercise testing VO2 before (left)
and after (right) first septal ablation
As primarily intended we decided to perform a second PTSMA for reduction of the mid-ventricular obstruction. Myocardial-contrast-echo guided PTSMA was successfully performed with the injection of 2 cc alcohol in the distal side branch of the first septal branch without complications (Fig. 8). Maximum CK rise was 762 U/l.
Fig. 8: Left coronary artery during second PTSMA with occlusion
of the distal side branch (arrow) of the first septal perforator.
Echocardiography after one week showed thinning of the septum and complete reduction of the LV-obstruction midventricular and subaortic (Fig. 9).
Clinical follow-up after 3 months was uneventful. ICD shocks had not been detected since the first PTSMA.
Fig. 9: Systolic 4 - chamber-view after second septal ablation
In this case we could demonstrate that treatment of symptomatic HOCM is complex including risk stratification for the prevention of SCD and a strategy for gradient reduction.
In the last decade it could be shown that septal ablation in symptomatic patients with HOCM results in ongoing relief of clinical symptoms in more than 90% of the patients. This could be shown not only in patients with subaortic obstruction, but also in patients with mid-ventricular obstruction.2 Hospital mortality could be reduced to nearly 0% in experienced centres with knowledge of the special problems and complexities that can emerge in the postinterventional period. In our own series 700 consecutive patients had been treated without hospital death since February 2001. Therefore, the need for permanent pacemaker implantation in less than 10% of patients treated is in fact the most significant complication.
Although in our patient we can present only mid-term follow-up without negative clinical events this case could support reported positive long-term effects after successful PTSMA. 3
Overall, septal ablation as well as surgical myectomy should be limited to experienced centers.
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