A 59-year-old man with a history of chronic obstructive pulmonary disease presented to the emergency room with severe sinus bradycardia and hypotension. Due to his history of recurrent dizziness and presyncope, prior work up with Holter cardiac event monitor showed predominant sinus bradycardia with no evidence of chronic incompetence and no clear correlation of his symptoms to the bradycardia episodes. His most recent echocardiogram showed normal left ventricular systolic function and wall motion. Myocardial perfusion study done for recurrent chest pain showed normal myocardial perfusion and normal ejection fraction on Gated SPECT. Tilt table test was markedly abnormal consistent with severe dysautonomia. His baseline blood pressure was 113/70 mmHg, and his HR was 49 beats per minute. Only two minutes into the test, his blood pressure dropped to 60/29 mmHg while his heart rate remained at 47 bpm. The patient was offered pacemaker therapy after his abnormal tilt table test but he refused.\nA few weeks later, the patient presented to the emergency room with syncope. Initial ECG showed severe sinus bradycardia, heart rate in the low 40 s with normal PR interval, and left anterior fascicular block. He was hypotensive and diaphoretic. He denied any chest pain, pressure, or tightness. There were no significant signs of cerebral hypoperfusion. The patient was not on any bradycardia-inducing medications, and initial blood work showed no reversible cause of his severe sinus bradycardia.\nThe patient was started on intravenous fluid hydration, and a bedside echocardiogram was obtained. Echocardiogram showed normal biventricular systolic function and no significant valvular abnormalities. Atropine was given but resulted in minimal, transient improvement in his heart rate to the low 50 s. The systolic blood pressure remained below 80 mmHg. Dopamine followed by norepinephrine drips were administered, and the patient was sent to the electrophysiology laboratory for dual-chamber permanent pacemaker therapy.\nDuring implantation of a permanent pacemaker, the right atrial lead was appropriately placed via the left subclavian vein into the right atrial appendage. However, the ventricular lead was placed via the subclavian artery into the left ventricular cavity. He was admitted to the hospital overnight and a chest X-ray was obtained the next day, showing no evidence of pneumothorax (Figure ). Surprisingly, his ECG showed atrial pacing with long AV delay and intermittent ventricular pacing with the paced ventricular beats showing right bundle branch block morphology contrary to the expected left bundle branch block morphology seen when the lead is inside the right ventricular cavity (Figure ). A limited bedside Echo was obtained that showed the ventricular lead clearly crossing the aortic valve to the left ventricular cavity and fixed into the inferolateral wall of the left ventricle (Figure ). Early recognition of this serious pacemaker implantation complication led to pacemaker revision the same day with extraction of the arterial lead and reinsertion of the ventricular lead via the left subclavian vein into the right ventricular cavity (Figure ). The pacemaker revision went uncomplicated.
A 78 year-old man with a history of paroxysmal atrial fibrillation (AF) presented with syncope and underwent implantation of a dual-chamber Medtronic KDR703 pacemaker while in AF. A Medtronic 4068 ventricular lead was implanted and found to have a threshold of 1.2 Volts (V) at 0.5 ms, a current of 1.8 milliamps and an impedance of 887 ohms. R-wave sensing was noted to be 16.6 mV. A Medtronic 4568 atrial lead was implanted but threshold testing was not performed and sensing was not reported. The pacemaker was programmed to VVIR 60-120.\nTwo months later, the patient developed left upper extremity weakness and a computed-tomography (CT) scan confirmed the clinical diagnosis of a right parietal cerebrovascular accident (CVA). The CVA was attributed to thromboembolism secondary to AF and the patient was initiated on warfarin therapy with a target INR of 2.0-3.0.\nThe patient was referred to our clinic after his ventricular lead was noted to have low impedance and a decrease in sensed R wave amplitude on routine interrogation. The patient's ECG is shown (). The diagnosis of inappropriate lead placement in the LV was suspected on the basis of the paced right bundle branch block (RBBB) pattern noted on this ECG. The diagnosis was confirmed by anterior and lateral chest radiography (). A non-contrast chest CT scan shows the ventricular lead coursing from the right atrium into the left atrium (LA) through an atrial septum defect (ASD) ().\nDevice interrogation revealed a ventricular lead threshold of 1.25 V at 0.4 ms, R wave sensing of 2.8-4.0 mV and a lead impedence of 248 ohms. The patient was in AF during interrogation with a slow, irregular ventricular response. No atrial capture could be demonstrated and no P waves were sensed.\nDue to suspected ventricular lead dysfunction and concern that sudden loss of ventricular pacing would lead to a recurrence of syncope, the patient underwent lead revision. A St. Jude 1688 lead was inserted into the right ventricle under fluoroscopic guidance using anterior and lateral views and the existing atrial lead and LV lead were capped. The patient's warfarin dose was increased to achieve a target INR of 2.5-3.5. The patient was discharged home without event. At the time of this report submission, the patient has had no further TE complications. Given the patient's age and comorbidities, should he experience further TE complications despite appropriate anticoagulation or if he develops an absolute contraindication to warfarin, we would consider percutaneous LV lead extraction with on-site cardiothoracic surgery back-up.