Case #12 — Varying Morphology of QRS Complexes: A Possible Explanation

by Rida Laeeq, MD, Mark Pollet, MD, Nadeen Faza, MD, and Yochai Birnbaum, MD

A 62-year-old man with nonischemic cardiomyopathy (left ventricular [LV] ejection fraction, 0.30–0.34) presented for evaluation of weakness. In 2011, he had undergone placement of a D224TRK Consulta® CRT-D (Medtronic, Inc.; Minneapolis, Minn) biventricular implantable cardioverter-defibrillator. The pacemaker, programmed in DDD mode, had a lower rate limit of 60 beats/min (cycle length, 1,000 ms) and an upper limit of 130 beats/min (cycle length, 430 ms), a paced atrioventricular (AV)-delay period of 130 ms, and a sensed AV-delay period of 100 ms. The LV lead threshold was 1.25 V at 0.6 ms and was programmed to deliver 1.75 V at 0.6 ms. The right atrial and right ventricular leads were in standard positions. The electrocardiogram appeared as follows (Fig. 1).

Case #11 — Is the Pacemaker Functioning Properly?

Alexander Postalian, MD, Mohammad Saeed, MD, J. Alberto Lopez, MD, and Yochai Birnbaum, MD

A 93-year-old woman with no symptoms was admitted to the hospital for a pacemaker generator exchange. She had a history of ischemic cardiomyopathy and was taking optimal medical therapy. She had also experienced paroxysmal atrial arrhythmia, which had been treated with atrioventricular node ablation and dual-chamber permanent pacemaker implantation. Upon her arrival, a 12-lead electrocardiogram was obtained (Fig. 1).

Case #10 — Bigeminy and a Pacemaker

by Luke Cunningham, MD, and Yochai Birnbaum, MD

An 81-year-old woman with a medical history of coronary artery disease, paroxysmal atrial fibrillation, and sick sinus syndrome, and implantation in 2013 of an AltruaTM dual-chamber pacemaker (Boston Scientific Corporation; Natick, Mass), presented after device interrogation revealed elevated impedance of >2,500 Ω in her atrial lead. The device settings were DDD mode, a lower rate limit of 60 beats/min, and a maximum atrioventricular (AV) delay of 330 ms. She reported fatigue, dyspnea on exertion, and occasional palpitations. She was admitted for new atrial lead implantation, and an electrocardiogram was obtained (Fig. 1).

Case #9 — Evaluation of Chest Pain after Implantable Cardioverter-Defibrillator Placement

by Amir Gahremanpour, MD, Mohammad Saeed, MD, and Yochai Birnbaum, MD

A 65-year-old woman with a history of congestive heart failure presented at the emergency department with right-sided upper-chest and shoulder discomfort. Two months prior, she had been given a single-lead Fortify Assura™ VR 1357-40Q implantable cardioverter-defibrillator (ICD) (St. Jude Medical, now part of Abbott Laboratories; St. Paul, Minn). She described her symptoms, which had started 6 hours before admission, as off-and-on pain of mild-to-moderate severity that was not associated with exertion or respiration. She reported no shortness of breath, cough, fever, chills, or dizziness. An electrocardiogram (ECG) was obtained upon presentation (Fig. 1).

Case #8 — A “De-Synching” Feeling

by David A. Burkland, MD, Mohammed Saeed, MD, FACC, and Yochai Birnbaum, MD, FACC

A 78-year-old man presented with worsening dyspnea and edema. He had undergone coronary artery bypass grafting in 2001. At the current presentation, he had ischemic cardiomyopathy with a left ventricular (LV) ejection fraction of 0.20 and was taking home inotropic therapy. Two months previously, he had begun cardiac resynchronization therapy with use of an implanted biventricular pacemaker.

Physical examination revealed elevated jugular venous pressure, bibasilar crackles, and pitting edema above both knees. An electrocardiogram (ECG) was obtained (Fig. 1).

Case #7 — Electrocardiogram Interpretation in a Man with Alcohol Withdrawal and Hypothermia

by Joanna Troulakis, MD, Roman Zeltser, MD, and Amgad N. Makaryus, MD

A 60-year-old man with paroxysmal atrial fibrillation, hypertension, seizure disorder, and alcohol abuse was unresponsive on presentation at the hospital. Laboratory tests revealed hypokalemia (2.5 mg/dL), hypomagnesemia (1.3 mg/dL), and no elevation in cardiac biomarkers. The patient’s admission electrocardiogram (ECG) showed an undetermined rhythm, with further interpretation limited by motion artifact. He was admitted with a diagnosis of alcohol withdrawal and hypothermia. During his hospital stay, he was monitored on telemetry for cardiac manifestations of electrolyte abnormalities. The covering physician was urgently called for suspicious telemetry events that prompted the completion of the following ECG (Fig. 1).