Abstract 64 Alcohol septal ablation in atypical midseptal HOCM sometimes requires the use of atypical septal branches for successful intervention

INTRODUCTION: Alcohol septal ablation (ASA) is an alternative to surgical myectomy in patients with severe typical hypertrophic obstructive cardiomyopathy (HOCM). However, only a few case reports demonstrated successful interventional or surgical treatment of atypical midseptal or apical forms of obstruction. We report a rare case of severe atypical HOCM that could be successfully treated via a septal branch of the right coronary artery.

CASE REPORT: A 69-year-old women was admitted to our institution for therapy of a severe atypical HOCM. She was in NYHA functional class III despite betablocker therapy and experienced exercise-related syncope. The HCM-SCD-risk-sore was calculated 5.6%. A VVI-ICD has already been implanted by the referring center. TTE showed a severe midseptal obstruction with gradients > 120 mmHg at rest and > 240 mmHg exercise-induced (75 W bicycle ergometry).

ASA-INTERVENTION: In 10/2020 ASA was ineffective after ablating the fifth and the sixth septal branch of the LAD (3.4 ml ethanol 98%). The site of obstruction could be confirmed in the midseptal area of the left ventricle (figure 1). 6 months later there was no improvement of the intraventricular obstruction and, hence, a second ASA-procedure was performed. This time a distal septal branch of the R. interventricularis posterior of the right coronary artery, that precisely matched the target area of obstruction, could be identified. A 1.5/8 mm OTW PCI-balloon was inserted into this branch easily and a total of 2.8 ml ethanol was injected. ST-segment-elevation in II, III, aVF could be observed in the surface-ECG during alcohol injection. The midventricular gradient decreased from 120 to 60 mmHg at rest and from 240 to 120 mmHg after provocation during ASA (figure 2). At 6 months follow-up the patient showed further reduction of the atypical obstruction (20 mmHg at rest, 40 mmHg exercise-induced) and also clinical improvement from NYHA functional class III to I. TTE showed a left ventricular function of 60% and a septal scar of the midventricular septum but no contraction disorder of the inferior wall of the left ventricle.

CONCLUSiON: ASA is safe and effective in atypical midseptal HOCM. The septal perforators of the right coronary artery should also be considered to perform ASA in complex cases.

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Clin Res Cardiol (2022). https://doi.org/10.1007/s00392-022-02087-y
Alcohol septal ablation in atypical midseptal HOCM sometimes requires the use of atypical septal branches for successful intervention – a case report
T. Lawrenz¹, D. Lawin¹, K. Marx¹, M. Poudel¹, C. Stellbrink¹
¹Klinik für Kardiologie und intern. Intensivmedizin, Klinikum Bielefeld Mitte, Bielefeld;
INTRODUCTION: Alcohol septal ablation (ASA) is an alternative to surgical myectomy in patients with severe typical hypertrophic obstructive cardiomyopathy (HOCM). However, only a few case reports demonstrated successful interventional or surgical treatment of atypical midseptal or apical forms of obstruction. We report a rare case of severe atypical HOCM that could be successfully treated via a septal branch of the right coronary artery. CASE REPORT: A 69-year-old women was admitted to our institution for therapy of a severe atypical HOCM. She was in NYHA functional class III despite betablocker therapy and experienced exercise-related syncope. The HCM-SCD-risk-sore was calculated 5.6%. A VVI-ICD has already been implanted by the referring center. TTE showed a severe midseptal obstruction with gradients > 120 mmHg at rest and > 240 mmHg exercise-induced (75 W bicycle ergometry). ASA-INTERVENTION: In 10/2020 ASA was ineffective after ablating the fifth and the sixth septal branch of the LAD (3.4 ml ethanol 98%). The site of obstruction could be confirmed in the midseptal area of the left ventricle (figure 1). 6 months later there was no improvement of the intraventricular obstruction and, hence, a second ASA-procedure was performed. This time a distal septal branch of the R. interventricularis posterior of the right coronary artery, that precisely matched the target area of obstruction, could be identified. A 1.5/8 mm OTW PCI-balloon was inserted into this branch easily and a total of 2.8 ml ethanol was injected. ST-segment-elevation in II, III, aVF could be observed in the surface-ECG during alcohol injection. The midventricular gradient decreased from 120 to 60 mmHg at rest and from 240 to 120 mmHg after provocation during ASA (figure 2). At 6 months follow-up the patient showed further reduction of the atypical obstruction (20 mmHg at rest, 40 mmHg exercise-induced) and also clinical improvement from NYHA functional class III to I. TTE showed a left ventricular function of 60% and a septal scar of the midventricular septum but no contraction disorder of the inferior wall of the left ventricle. CONCLUSiON: ASA is safe and effective in atypical midseptal HOCM. The septal perforators of the right coronary artery should also be considered to perform ASA in complex cases. .
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