A 76-year-old man with history of ischemic cardiomyopathy and paroxysmal atrial fibrillation who underwent a Dual-Chamber Medtronic Implantable Cardioverter-Defibrillator (ICD) placement 6 years earlier in an outside facility presented to the emergency room with worsening shortness of breath. Initial workup in the emergency room revealed acute on chronic combined congestive heart failure. An AP chest X-ray film was interpreted by the radiologist as cardiomegaly with pulmonary vascular congestion and satisfactory ICD lead position (Figure ). No lateral view was obtained at the time.\nBedside Echo showed severely reduced left ventricular systolic function with dilated right ventricle and moderate-to-severe pulmonary hypertension. Surprisingly, the ICD lead was clearly going from the left atrium through the mitral valve to the left ventricular cavity (Figures , , and ). A lateral chest X-ray view revealed that the ICD shock lead tip is directed posteriorly, indicating its presence in the left ventricular cavity (Figure ). A transesophageal echocardiogram showed the ICD lead went from the superior vena cava to the right atrium, crossing through a small sinus venous atrial septal defect to the left atrium, and into the left ventricular cavity via the mitral valve. Luckily, the patient was on chronic anticoagulant because of chronic atrial fibrillation, so no thromboembolic complications were reported. Interestingly enough, the patient had two prior trans-thoracic echocardiograms that were interpreted by the same cardiologist without mention of abnormal ICD lead placement. Furthermore, prior ICD interrogation reports from his primary cardiologist showed chronically elevated shock lead impedance but pacing threshold and sensing were good. No therapy was needed since device implantation.\nBecause extraction of a chronically implanted ICD lead carries a high risk of major cardiovascular complications (2%-4%) including vascular injury, cardiac perforation resulting in cardiac tamponade, and occasionally thromboembolic complications or even death, and because the patient was chronically anticoagulated, the decision is made to continue conservative management.
A 71-year-old female patient who was diagnosed as “rheumatic valvular heart disease, mitral stenosis and insufficiency” underwent mitral valve replacement in our thoracic surgery department two years ago. After the operation, amiodarone (0.2 mg bid) was administrated to the patient for a long time because of paroxysmal atrial fibrillation. Four days before admission, she suffered from dizziness without syncope or amaurosis, and then came to our emergency room. Electrocardiogram (ECG) indicated atrial fibrillation with slow ventricular rates (37–38/min). Cardiac ultrasound demonstrated postoperative state of mitral valve replacement, enlargement of left atria and mild reflux of pulmonary valve. A temporary pacemaker was implanted before admission. The patient was diagnosed as “rheumatic valvular heart disease, postoperative state of mitral valve replacement, atrial fibrillation with slow heart rate, the state of temporary pacemaker implantation, chronic heart failure (NYHA IIclass), and diabetes”.\nAmiodarone was discontinued after admission. One week later, we regulated the rhythm of patient’s temporary pacemaker to 30/min. ECG monitor suggested the occurrence of significant sinus bradycardia with atrio-ventricular junctional escape beat, and occasionally with pacing rhythm. Considering the degradation of patient’s sinuatrial node and atrioventricular node, a permanent dual-chamber pacemaker was prepared to be implanted. During the course of operation, patient suffered from chest distress, dyspnea, lung rales, and rapid atrial flutter in ECG, which suggested the aggravation of heart failure. After the treatment of oxygen, morphine (5 mg iv), and furosemide (20 mg iv), the patient was getting better. After operation, excess bleeding was found on the puncture site. Considering the severity of patient’s disease and poor operation endurance, a single-chamber pacemaker (PhilosIISR, BIOTRONIK Company) was chosen to take place of dual-chamber pacemaker after contacting with patient’s relatives. Parameters settings of the single-chamber pacemaker were demonstrated as follows: the threshold of ventricular pacing was 0.8 V (0.5mS); the amplitude of R wave was 30.1mv; and the electrode impedance was 856Ω.\nBoth pacemaker function and Holter indicated favorable behavior of the pacemaker after the operation, and stitches were taken out one week later. Nine days later, the reexamination of cardiac ultrasound demonstrated as follows: postoperative state of mitral valve replacement, normal artificial biological mitral valve, enlargement of left atria, mild reflux of aortic valve, mitral valve flow spectrum showing a single peak, and pacemaker in ascending aorta and left ventricle (Fig. ). Chest computed tomography (CT) scan indicated that the pacemaker electrode was put into aorta and left ventricular (Fig. ), which suggested that the pacemaker had been put into subclavian artery by mistake and the pacing electrode was implanted in the left heart.\nTraditional right ventricular apical pacing belongs to unphysiological pacing, while the most studied physiological pacing regions include right ventricular outflow tract (RVOT) and septum, which can improve patients’ heart function [, ]. However, various complications may appear during the course of RVOT and right ventricular septum pacing and increase the risk of operation, such as high threshold of pacing, difficult fixation and location of pacing leads, long-duration operation, easy dislocation, and even the cardiac perforation etc. [–]. Cardiac resynchronization therapy (CRT) has been widely applied in clinics to conduct left ventricular epicardial pacing via coronary sinus currently. However, it is difficult to conduct left ventricular endocardial pacing via the puncture site of atrial septum because of the occurrence of side-effects, such as high risk of thromboembolism, impact on the function of mitral valve, and myocardial damage caused by taking out the pacemaker. Therefore, we reported a case that pacemaker was implanted into left ventricle by mistake which made unnecessary troubles to our doctors.\nIn this case, patient’s diagnosis was definite. On October 6, 2014, a cardiac permanent pacemaker was implanted because the patient was suffering from atrial fibrillation and atrial flutter with sinus bradycardia (30-40/min). The reexamination of cardiac ultrasound demonstrated that the pacing leads were put into left heart, which suggested that pacing electrode was implanted into left ventricle via subclavian artery by mistake. The reasons included: 1) during the course of operation, patient’s heart function aggravated suddenly. Excess bleeding was observed after we performed a puncture on her subclavian artery by mistake. However, we regarded the excess bleeding and the increase of blood pressure as the results of the rise of central venous pressure caused by the aggravation of heart failure. Moreover, acute heart failure could result in hypoxia, which made troubles in recognizing whether the blood was from artery or vein; 2) after the pacing leads were implanted, the fluoroscopy should have been conducted in post-anterior view, 45-degree left anterior oblique view and 30-degree right anterior oblique view, respectively []. However, after the occurrence of chest distress, drugs were administrated to treat acute heart failure immediately, which also induce the operator to shorten the duration of operation. In addition, angiography has not been performed to confirm the location of pacing leads, and multiple body position fluoroscopy wasn’t conducted as well after the implantation of pacing electrode, while post-anterior view scanning during the course of operation couldn’t confirm the location of pacing electrode accurately (Fig. ); 3) it was easy to locate the passive electrode in traditional right ventricular apical pacing. In addition, the temporary pacing is implanted in the right ventricular apex generally, which is relatively helpful to locate the passive electrode in the right ventricular apex also. However, in our operation, the active electrode was used and prepared to implant into ventricular septum, which was difficult to locate. And it was hard to be located with the reference of the temporary pacemaker, which was normally positioned in the right ventricular apex. Therefore, we unfortunately mistook left ventricle for right ventricular low septum, and then the pacing electrode was implanted into left ventricle; 4) the electrocardiogram (ECG) after the pacemaker implantation is helpful in locating pacemaker. For example, the left bundle-branch block showed in ECG is common seen in right ventricular paced patients (Fig. ), while the right bundle-branch block in left ventricular paced patients. In this case, the patient suffered a sudden heart failure. The ECG suggested rapid atrial flutter without any pacemaker signal (Fig. ). Therefore, it was unable to evaluate the position of the lead through ECG.