iPhone ECG monitoring — the gateway to the new paradigm of STEMI therapy

Comparison of smartphone-based and standard base-apex electrocardiography in healthy dairy cows

BACKGROUND

There is good diagnostic accuracy of smartphone-based ECG in the evaluation of heart rate (HR), heart rhythm, and ECG values for humans, horses, dogs, and cats.

OBJECTIVES

Assess feasibility and reliability of a smartphone ECG device to evaluate HR expressed as beats per minute and ECG values in cows.

ANIMALS

Fifty-five healthy Holstein Friesian cows.

METHODS

Prospective observational study. A standard base-apex ECG was acquired for 60 seconds in each cow. A smartphone ECG tracing was recorded simultaneously using a single-lead bipolar ECG recorder. All ECGs were reviewed by 1 blinded investigator. The following ECG variables were assessed: HR, P wave duration, PR interval, QRS complex and QT interval (milliseconds), P wave, and QRS complex polarity. Agreement between standard and smartphone ECG was evaluated by Cohen's k test and the Bland-Altman test.

RESULTS

Smartphone ECG tracings were interpretable in 89% of the recordings. Minimal differences of no clinical relevance were found between standard and smartphone ECG tracings regarding HR and duration of ECG waves and interval. Good agreement found in the evaluation of QRS complex polarity (85%) but not for P wave polarity (k = 0.006). Artifacts were rare but of significantly higher frequency in smartphone ECG compared to standard ECG tracings (22% versus 0%; P = .005).

CONCLUSIONS AND CLINICAL IMPORTANCE

Good quality single-lead ECG tracings can be recorded by smartphone device in healthy cows. Smartphone tracings are reliable for evaluation of HR and selective ECG variables. Smartphone ECG can represent an additional tool for ECG screening in cows.

Identifying Patients at Risk for Prehospital Sudden Cardiac Arrest at the Early Phase of Myocardial Infarction

Background:

In-hospital mortality of ST-segment–elevation myocardial infarction (STEMI) has decreased drastically. In contrast, prehospital mortality from sudden cardiac arrest (SCA) remains high and difficult to reduce. Identification of the patients with STEMI at higher risk for prehospital SCA could facilitate rapid triage and intervention in the field.

Methods:

Using a prospective, population-based study evaluating all patients with STEMI managed by emergency medical services in the greater Paris area (11.7 million inhabitants) between 2006 and 2010, we identified characteristics associated with an increased risk of prehospital SCA and used these variables to build an SCA prediction score, which we validated internally and externally.

Results:

In the overall STEMI population (n=8112; median age, 60 years; 78% male), SCA occurred in 452 patients (5.6%). In multivariate analysis, younger age, absence of obesity, absence of diabetes mellitus, shortness of breath, and a short delay between pain onset and call to emergency medical services were the main predictors of SCA. A score built from these variables predicted SCA, with the risk increasing 2-fold in patients with a score between 10 and 19, 4-fold in those with a score between 20 and 29, and >18-fold in patients with a score ≥30 compared with those with scores <10. The SCA rate was 28.9% in patients with a score ≥30 compared with 1.6% in patients with a score ≤9 ( P for trend <0.001). The area under the curve values were 0.7033 in the internal validation sample and 0.6031 in the external validation sample. Sensitivity and specificity varied between 96.9% and 10.5% for scores ≥10 and between 18.0% and 97.6% for scores ≥30, with scores between 20 and 29 achieving the best sensitivity and specificity (65.4% and 62.6%, respectively).

Conclusions:

At the early phase of STEMI, the risk of prehospital SCA can be determined through a simple score of 5 routinely assessed predictors. This score might help optimize the dispatching and management of patients with STEMI by emergency medical services.

Diagnostic accuracy of a smartphone electrocardiograph in dogs: Comparison with standard 6-lead electrocardiography

The diagnostic accuracy of a smartphone electrocardiograph (ECG) in evaluating heart rhythm and ECG measurements was evaluated in 166 dogs. A standard 6-lead ECG was acquired for 1 min in each dog. A smartphone ECG tracing was simultaneously recorded using a single-lead bipolar ECG recorder. All ECGs were reviewed by one blinded operator, who judged if tracings were acceptable for interpretation and assigned an electrocardiographic diagnosis. Agreement between smartphone and standard ECG in the interpretation of tracings was evaluated. Sensitivity and specificity for the detection of arrhythmia were calculated for the smartphone ECG. Smartphone ECG tracings were interpretable in 162/166 (97.6%) tracings. A perfect agreement between the smartphone and standard ECG was found in detecting bradycardia, tachycardia, ectopic beats and atrioventricular blocks. A very good agreement was found in detecting sinus rhythm versus non-sinus rhythm (100% sensitivity and 97.9% specificity). The smartphone ECG provided tracings that were adequate for analysis in most dogs, with an accurate assessment of heart rate, rhythm and common arrhythmias. The smartphone ECG represents an additional tool in the diagnosis of arrhythmias in dogs, but is not a substitute for a 6-lead ECG. Arrhythmias identified by the smartphone ECG should be followed up with a standard ECG before making clinical decisions.

A Smartphone Application to Diagnose the Mechanism of Pediatric Supraventricular Tachycardia

Smartphone applications that record a single-lead ECG are increasingly available. We sought to determine the utility of a smartphone application (AliveCor) to record supraventricular tachycardia (SVT) and to distinguish atrioventricular reentrant tachycardia (AVRT) from atrioventricular nodal reentrant tachycardia (AVNRT) in pediatric patients. A prior study demonstrated that interpretation of standard event and Holter monitors accurately identifies the tachycardia mechanism in only 45 % of recordings. We performed an IRB-approved prospective study in pediatric patients undergoing an ablation for SVT. Tracings were obtained by placing the smartphone in three different positions on the chest (PI-horizontal, PII-rotated 60° clockwise, and PIII-rotated 120° clockwise). Two blinded pediatric electrophysiologists jointly analyzed a pair of sinus and tachycardia tracings in each position. Tracings with visible retrograde P waves were classified as AVRT. The three positions were compared by Chi-square test. Thirty-seven patients (age 13.7 ± 2.8 years) were enrolled in the study. Twenty-four had AVRT, and 13 had AVNRT. One hundred and eight pairs of tracings were obtained. The correct diagnosis was made in 27/37 (73 %) with position PI, 28/37 (76 %) with PII, and 20/34 (59 %) with PIII (p = 0.04 for PII vs. PIII and p = NS for other comparisons). A single-lead ECG obtained with a smartphone monitor can successfully record SVT in pediatric patients and can predict the SVT mechanism at least as well as previously published reports of Holter monitors, along with the added convenience of not requiring patients to carry a dedicated monitor.

Early text page alarms sent to cardiologists reduce door-to-balloon times in ST-elevation myocardial infarction

We assessed an early notification system using smartphones to reduce door-to-balloon times (DTBT) in ST-elevation myocardial infarction (STEMI). Text page alarms were sent to cardiologists for all patients presenting with chest pain or an equivalent in the emergency department before acquisition of an electrocardiogram (ECG). A total of 210 patients (with mean age of 59 years) were investigated (109 in the intervention group and 101 in a control group from the previous two-year period). The primary outcome, the DTBT, was significantly lower in the intervention group compared to the control group (55.0 and 92.5 min, respectively, P < 0.001). In a secondary analysis, the length of hospital stay was also significantly less. However, there was no significant improvement in all-cause one-year mortality. Early text page alarms using smartphones were effective in reducing the DTBT, but had a limited effect on clinical outcome.

Reperfusion therapy for ST-segment elevation myocardial infarction: has ECG information been underutilized?

This perspective makes a contentious viewpoint that ECG information is underutilized in ST-segment elevation myocardial infarction (STEMI) and the next breakthrough rests on its full utilization. This is to better diagnose difficult cases such as ST changes during bundle branch block, posterior ST elevation and right-sided ST elevation during normal conduction, and aVR ST elevation. More importantly, this is to better characterize the STEMI for tailored reperfusion. The proposal is to develop a system capable of recording from multiple electrodes that one can apply onto oneself, and having analysis coordinated centrally via phone-internet transmission. This provides 'longitudinal' in addition to 'cross-sectional' ECG information. STEMI will be classified on a gray-scale according to its potential size and speed of Q wave evolution. The hypothesis is that large rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt transferral to a percutaneous coronary intervention center; while small stuttering STEMI is best treated by primary percutaneous coronary intervention despite a long delay.