Current status of implantable defibrillator devices in patients with left ventricular dysfunction — The first report from the online registry database

Background: The current status of the efficacy of implantable cardioverter-defibrillator (ICD. and cardiac-resynchronization therapy with implantable defibrillator (CRT-D. in patients with left ventricular dysfunction needs to be clarified. Methods and Results: From the Japanese Cardiac Device Treatment Registry database, a total of 1,584 patients who had an LVEF ≦ 40% and had an ICD or CRT-D were selected as subjects in this study. The difference in the clinical characteristics between the primary and secondary prevention groups and the transition of the indications for device implantation over time were examined. Primary prevention gradually increased up to about 50% in all patients. The implantations of ICD/CRT-D for primary prevention in ischemic hear disease was significantly lower than that in dilated cardiomyopathy (33% vs 51%; p < 0.0001). The number of implantations for CRT-D for primary prevention increased dramatically over a one-year period. Conclusions: In Japan, the implantable defibrillator devices for primary prevention was significantly lower in ischemic heart disease compared with dilated cardiomyopathy. Further, an extension of the indications for ICD/CRT-D implantations has recently been occurring, especially with CRT-D devices for primary prevention

Elongated ascending aorta predicts a short distance between his-bundle potential recording site and coronary sinus ostium

Background: When performing catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), it can be difficult to maintain a safe distance from the His recording site to avoid AV block in patients with a short distance between this recording site to the coronary sinus (CS) ostium (small triangle of Koch [TOK]). In this study, we sought to identify parameters predicting small TOK and test these parameters in patients undergoing AVNRT catheter ablation. Methods: Twenty-eight patients who underwent catheter ablation of atrial fibrillation using a three-dimensional (3D) electroanatomical mapping system (EAM) with computed tomography (CT) merge (23 males; mean age, 65.8±12.1 years) were included. The shortest distance between the CS ostium and His recording sites (His-CSd) was measured on the EAM. Aortic (Ao) unfolding in chest X-ray scan, Ao angle to the LV, Ao length, Ao to the right ventricular distance, size of the Valsalva in the CT scan, and parameters of echocardiogram were evaluated. The identified parameters were subsequently tested as predictors for small TOK in patients undergoing AVNRT ablation. Results: The size of TOK was associated with Ao length (r = −0.70, p<0.01), left ventricular end-systolic dimension (LVDs) (r = −0.51, p<0.01), and Ao unfolding. In patients with AVNRT, only Ao unfolding predicted a smaller TOK. Conclusions: Small TOK was associated with longer Ao, larger LVDs, and Ao unfolding. Of these, Ao unfolding was associated with smaller TOK in patients with AVNRT

A case of complete atrioventricular block: The use of magnetic resonance imaging conditional pacemakers for diagnosing cardiac sarcoidosis

A 50-year-old man presented to the emergency department with repeated episodes of faintness and exertional dyspnea, and was found to have an atrioventricular (AV) block. Chest radiography and transthoracic echocardiography results were normal, without any evidence of heart failure, wall motion abnormalities, interventricular septum thinning, or bilateral hilar lymphadenopathy. A temporary pacemaker was implanted, followed by a permanent pacemaker. Chest computed tomography with contrast enhancement did not show abnormalities, including patent coronary arteries, lymph node adenopathy, and pulmonary abnormalities. Thus, an MRI conditional dual chamber pacemaker and leads were implanted. Six weeks following the implant, a cardiac MRI was performed to test for cardiac sarcoidosis. Although cine imaging showed normal left and right ventricular function, late gadolinium enhancement demonstrated multiple enhanced uptakes. Based on the results of the cardiac MRI, PET, and gallium scintigraphy, the most likely diagnosis was cardiac sarcoidosis. Although no abnormal findings were found on physical examination, blood work, chest radiography, and transthoracic echocardiogram, multiple regions of delayed enhancement were observed in the cardiac MRI. Thus, MRI conditional pacemakers are a useful tool for diagnosing cardiac sarcoidosis and early therapeutic intervention

Brain magnetic resonance imaging examination in a patient with non-magnetic resonance conditional pacemaker

Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker are required to undergo magnetic resonance imaging (MRI). We encountered a pacemaker patient with debilitating non-motor symptoms of Parkinson׳s disease, who required an MRI prior to deep brain stimulation (DBS) surgery. MRI was performed safely without adverse events despite the presence of a conventional pacemaker