br Conflict of interest br Disclosures br Acknowledgments
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Patient presentation A 64-year-old male with a history of a right ventricular outflow tract ventricular tachycardia (RVOT-VT) ablation presented from an outlying hospital due to four recent episodes of non-exertional syncope. He had three witnessed episodes at home but did not receive medical workup until he BIBW 2992 presented to an outlying ED after the fourth episode. He was sitting at home and became unresponsive for 2–3min and awoke confused. Patient reported a 2–3s prodrome of dysphoria. In the ED on telemetry a fifth syncopal episode occurred, lasting 102s. He was in ventricular fibrillation (VF) without evidence of QT prolongation (Fig. 1). He awoke with normal vital signs and normal sinus rhythm. 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.  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.  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.  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.  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  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 cycle length (CL) than benign RVOT-VT (245±28 vs. 328±65ms, p<.0001) .
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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 . 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 . 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.