Validation of a smartphone-based event recorder for arrhythmia detection.

INTRODUCTION: Ambulatory cardiac monitoring devices such as external loop recorders (ELRs) are often used in the outpatient clinic to evaluate palpitations. However, ELRs can be bulky and uncomfortable to use, especially in public, at work, or in social situations. An alternative approach is a smartphone-based electrocardiographic (ECG) recorder/event recorder (Kardia Mobile [KM]), but the comparative diagnostic yield of each approach has not been studied. METHODS: Thirty-three patients with palpitations wore an ELR and carried a KM for a period of 14-30 days. They were instructed to transmit ECGs via KM and also to activate the ELR whenever they had symptoms. The tracings obtained from both devices were independently analyzed by two cardiologists, and the overall arrhythmia yield, as well as patient preference and compliance, were evaluated. The paired binomial data obtained from both devices were compared using an unconditional test of noninferiority. RESULTS: Of the 38 patients enrolled in the study, more patients had a potential diagnosis for their symptoms (i.e., at least one symptomatic recording during the entire monitoring period) with KM than with the ELR (KM = 34 [89.5%] vs ELR = 26 [68.4%]; χ2  = 5.1, P = 0.024). In the per protocol analysis, all 33 patients (100%) had a potential diagnosis using the KM device, which was significantly higher compared to 24 patients (72.2%) using the ELR (χ2  = 10.4, P = 0.001). CONCLUSIONS: KM is noninferior to an ELR for detecting arrhythmias in the outpatient setting. The ease of use and portability of this device make it an attractive option for the detection of symptomatic arrhythmias.

Screening for atrial fibrillation in high-risk nursing home residents.

BACKGROUND: Various methods have been implemented for screening of patients for atrial fibrillation (AF), but the yield has generally been low. Targeting high-risk patients may improve detection of asymptomatic AF, which could be of value if appropriate treatment could be initiated before a potential thromboembolic event. OBJECTIVE: The purpose of this study was to test screening of high-risk nursing home residents having ≥2 risk factors for AF and no previous history of AF using a smartphone-based electrocardiographic (ECG) monitoring device to determine whether it is an accurate, easy-to-use method of screening for asymptomatic AF. METHODS: Study participants had ≥2 risk factors, consisting of age ≥75 years, female sex, obstructive sleep apnea, peripheral vascular disease, diabetes mellitus, obesity, hypertension, and congestive heart failure. Using the monitoring device, 30-second heart rhythm recordings were obtained on 4 different occasions. All tracings were reviewed by a cardiologist and, if uncertain, by an electrophysiologist. The nursing facility was notified of any diagnosis of AF, prompting further evaluation by the primary physician. RESULTS: Of the 245 residents screened, 18 (7.4%) had a diagnostic tracing for AF, 15 (83.3%) of whom had AF on the initial screen. There were no significant differences in demographics or individual risk factors between residents with and those without AF. CONCLUSION: Intermittent ECG screening of high-risk nursing home residents using a simple, handheld device provided a diagnostic yield in our population comparable to that observed in past studies. Such screening of high-risk individuals can aid in the early diagnosis of AF and initiation of appropriate treatment.

Presumed hydrochlorothiazide-associated immunologic-hypersensitivity-induced pericardial effusion.

A 50-year-old Caucasian female presented for a second opinion regarding a newly diagnosed pericardial effusion. Seven months previously, hydrochlorothiazide was introduced into her pharmacologic regimen to aid in the management of her hypertension. A routine echocardiogram indicated a large pericardial effusion with signs of early cardiac tamponade. The patient subsequently underwent successful pericardiocentesis with complete drainage of the pericardial effusion. The effusion was empirically attributed to a viral etiology. Repeat echocardiograms showed recurrence of the pericardial effusion. Prior to undergoing a second pericardiocentesis with pericardial biopsy, as her physicians recommended, the patient sought a second opinion. While obtaining the patient's history, an allergy to sulfa was elicited. The possibility that the pericardial effusion may be secondary to an immunologic-hypersensitivity reaction was considered. It was recommended the patient discontinue the use of hydrochlorothiazide. Nine days following discontinuation of hydrochlorothiazide and without any other intervention, an echocardiogram was reported to show the size of the pericardial effusion had subsided substantially. Nine weeks following discontinuation, almost complete resolution of the pericardial effusion was reported. It is hypothesized that when treated with hydrochlorothiazide, the patient had an immune response leading to the pericardial effusion.