Simultaneous Leadless Pacemaker and Subcutaneous ICD Implantation With Intraoperative Screening: Workflow in Two Patients.

A communicating subcutaneous implantable cardioverter-defibrillator (ICD) and leadless pacemaker system is being developed for patients who require both pacing and ICD therapy. It is important to ensure that the paced morphology from the leadless pacemaker will be sensed appropriately by the subcutaneous ICD. We present 2 cases illustrating our approach and workflow. (Level of Difficulty: Intermediate.).

The Longer the Block, the Harder You Fall: Extrinsic Idiopathic Atrioventricular Block Masquerading as Seizures.

History and physical examination are the diagnostic cornerstones of transient loss of consciousness (TLOC). However, details can be scarce and examination unrevealing, thus making the diagnosis elusive. In a case of convulsive TLOC, the initial diagnosis was incorrect, but a fortuitously captured event on telemetry yielded the diagnosis: extrinsic idiopathic atrioventricular block. (Level of Difficulty: Beginner.).

Racial differences in the incidence of atrial fibrillation after cryptogenic stroke.

BACKGROUND: The incidence of atrial fibrillation (AF) is lower in nonwhites than in whites despite a higher burden of AF risk factors. However, the incidence of new AF after cryptogenic stroke in minorities is unknown. OBJECTIVE: The purpose of this study was to determine the incidence of AF after cryptogenic stroke in different racial/ethnic groups. METHODS: We retrospectively analyzed 416 consecutive patients undergoing insertable cardiac monitor implantation at our hospital from 2014 through 2019. Incidence of AF was identified through the review of device monitoring, including adjudication of AF episodes for accuracy, and compared by race. RESULTS: The mean follow-up time was 1.5 ± 1.1 years. The predominantly nonwhite cohort included 244 (59%) blacks and 109 (26%) Hispanics, and 45% (n=189) were male. The mean age was 62 ± 12 years; Blacks and Hispanics had more hypertension, diabetes, and chronic kidney disease and higher body mass index than did whites. In blacks and Hispanics, the cumulative incidences of AF at 1, 2, and 3 years were 14.1%, 19.9%, and 24% and 12.9%, 18.3%, and 20.9%, respectively. By comparison, the incidence in whites was significantly higher: 20.8%, 34.3%, and 40.3%. In a Cox proportional hazards model adjusting for common AF risk factors, blacks (hazard ratio 0.49; confidence interval 0.26-0.82; P = .03) and Hispanics (hazard ratio 0.39; confidence interval 0.18-0.83; P = .01) were less likely to have incident AF than whites. CONCLUSION: In patients with an insertable cardiac monitor after cryptogenic stroke, the incidence of newly detected AF is approximately double in whites compared with both blacks and Hispanics. This has important implications for the investigation and treatment of nonwhites with cryptogenic stroke.

Electrolyte Abnormalities in Patients Presenting With Ventricular Arrhythmia (from the LYTE-VT Study).

Electrolyte abnormalities are a known trigger for ventricular arrhythmia, and patients with heart disease on diuretic therapy may be at higher risk for electrolyte depletion. Our aim was to determine the prevalence of electrolyte depletion in patients presenting to the hospital with sustained ventricular tachycardia or ventricular fibrillation (VT/VF) versus heart failure, and identify risk factors for electrolyte depletion. Consecutive admissions to a tertiary care hospital for VT/VF were identified between July 2016 and October 2018 using the electronic medical record and compared with an equal number of consecutive admissions for heart failure (CHF). The study included 280 patients (140 patients in each group; mean age 63, 60% male, 59% African American). Average EF in the VT/VF and CHF groups was 30% and 33%, respectively. Hypokalemia (K < 3.5 mmol/L) and severe hypokalemia (K < 3.0 mmol/L) were present in 35.7% and 13.6%, respectively, of patients with VT/VF, compared to 12.9% and 2.7% of patients with CHF (p < 0.001 and p = 0.001, respectively, between groups). Hypomagnesemia was found in 7.8% and 5.8% of VT/VF and CHF patients, respectively (p = 0.46). Gastrointestinal illness and recent increases in diuretic dose were strongly associated with severe hypokalemia in VT/VF patients (odds ratio: 11.1 and 21.9, respectively; p < 0.001). In conclusion, hypokalemia is extremely common in patients presenting with VT/VF, much more so than in patients with CHF alone. Preceding gastrointestinal illness and increase in diuretic dose were strongly associated with severe hypokalemia in the VT/VF population, revealing a potential opportunity for early intervention and arrhythmia risk reduction.