At age he was diagnosed with RVOT VT after

At age 46 he was diagnosed with RVOT-VT after presenting with near syncope with exercise. A stress test revealed non-sustained runs of ventricular tachycardia (Fig. 2). ECG and echocardiogram were normal. The RVOT-VT ablation was straightforward with no complications. He was symptom-free until this admission 18 years later.
Discussion Noda et al. [1] describe the outcomes in five patients undergoing radiofrequency catheter ablation for idiopathic ventricular fibrillation and polymorphic VT. In all five patients episodes of syncope, VF, and cardiac arrest were eliminated. The authors discuss the possibility of a malignant entity of idiopathic VF or polymorphic VT arising from the RVOT. Willems et al. [2] review the mapping and ablation of VF. They note the spontaneous variation of the PVC occurrence and the demanding transaortic or transseptal mapping approach. The authors recommend performing the EP study acutely after the polymorphic VT/VF event due to the increased presence of PVCs. Viskin et al. [3] described three patients presenting with benign RVOT-VT who then developed malignant polymorphic VT or VF. The coupling intervals (CIs) of their patients with short coupled RVOT-VT were “intermediate,” significantly shorter than the values seen with uncomplicated RVOT-VT but longer than the values observed in idiopathic VF. Knecht et al. [4] reviewed 38 patients presenting with idiopathic VF. Patients with triggering PVCs originating from the RVOT showed a CI of 355±23ms versus 276±22ms (p<.001) for those PVCs originating from the Purkinje system. Shimizu [5] reviewed distinguishing characteristics of malignant forms of RVOT-VT, showing that the shorter coupling interval of initiating PVCs correlated with the more malignant form of RVOT-VT. Noda et al. looked at risk predictors suggesting that malignant RVOT-VT has a significantly shorter bace inhibitors length (CL) than benign RVOT-VT (245±28 vs. 328±65ms, p<.0001) [1].
Conclusions
Conflict(s) of interest
Introduction Anemia worsens obstructions in hypertrophic obstructive cardiomyopathy (HOCM). Mechanical intracardiac hemolysis has been proposed as a rare cause of anemia in patients with HOCM [1]. Here we present the case of a patient with HOCM complicated by intracardiac mechanical hemolysis that was dramatically controlled by dual-chamber pacing.
Case report A 59-year-old woman with HOCM was admitted to our institution with worsening heart failure (New York Heart Association [NYHA] class IV). She developed pulmonary hypertension and normocytic and normochromic anemia with a hemoglobin level of 8.6g/dL. Lactate dehydrogenase level was slightly increased, and the indirect bilirubin level was increased more than the direct bilirubin level. A peripheral blood smear revealed increased numbers of reticulocytes and slightly increased numbers of fragmented red blood cells (Fig. 1). Coombs test was negative. Based on the laboratory findings (Table 1), the cause of the anemia was thought to be mechanical intracardiac hemolysis due to a left ventricular outflow tract (LVOT) obstruction. The patient was initially treated with carvedilol 10mg daily, verapamil 120mg daily, and cibenzoline 300mg daily according to the Japanese Circulation Society guideline [2]. Her heart failure was refractory to medical therapy. Myectomy was chosen because repeated blood transfusions were required to improve her anemia and heart failure, and the LVOT pressure gradient (LVOT-PG) was >150mmHg. A thin, 2×5mm2 section of the myocardium was removed. During the surgery, a transient decrease in LVOT-PG was observed on transesophageal echocardiography and low blood pressure was noted. After inotropic support was discontinued, no decrease in LVOT-PG was noted, rather, it remained at 156mmHg just before implantable cardioverter defibrillator (ICD) implantation after myectomy (Fig. 2A). The ICD was indicated by the following findings: (1) documentation of nonsustained VT, (2) abnormal blood pressure response during exercise stress, (3) positive late ventricular potential, and (4) late gadolinium enhancement on cardiac magnetic resonance imaging. A dual-chamber ICD was then implanted and the optimal atrioventricular (AV) interval to obtain the lowest PG was adjusted to a sensed PV interval of 70ms/AV pace of 60ms using echocardiography. After 1 week, the LVOT-PG had decreased to 68mmHg (Fig. 2B); by 3 weeks, it had decreased to 26mmHg (Fig. 2C). The hemolysis was well controlled because of the decreased PG, and the patient was stabilized and discharged. After 3 months of treatment, her hemoglobin level remained at 12.3g/dL and her congestive heart failure improved from NYHA class IV to class II.
Discussion Mechanical intracardiac hemolysis has been reported as a rare cause of anemia in patients with HOCM [1]. LVOT obstruction causes hemolytic anemia, which then increases the left ventricular contractility and exacerbates LVOT obstruction and hemolytic anemia. This results in a vicious obstruction–anemia cycle.