K. Rajakariar

Modified positioning of a smartphone based single-lead electrocardiogram device improves detection of atrial flutter

INTRODUCTIONnThe AliveCor Kardia Mobile (AKM) is a handheld, smartphone based cardiac rhythm monitor that records a lead-I electrocardiogram (ECG). Despite being efficacious for detection of atrial fibrillation (AF), it is unclear whether atrial flutter (AFL) may be misdiagnosed as sinus rhythm due to regular R-R intervals. We hypothesised that generating lead-II tracings through repositioning of the AKM may improve visualisation of flutter waves and clinician diagnosis of AFL compared to traditional lead-I tracings.nnnMATERIALS AND METHODSnA prospective, multi-centre, validation study was conducted comparing standard lead-I AKM positioning with lead-II in AFL. A mixed cohort of lead I tracings from patients in AF and sinus rhythm were also included. Two independent electrophysiologists (EP) analysed all ECGs blinded to the automated device diagnosis.nnnRESULTSnFifty patients were recruited, 11 in atrial flutter, 14 in atrial fibrillation, and 25 in sinus rhythm. Lead-I AFL sensitivity was 27.3% for both EPs which individually improved to 72.7% and 54.6% in lead-II. AKM appropriately diagnosed lead-I AFL as unclassified in 18.2% of cases, compared to 54.5% in lead-II. Overall clinician agreement (AF, SR and AFL) was modest utilising AFL lead-I (EP1: κu202f=u202f0.71, EP2: κu202f=u202f0.73, pu202f<u202f0.001), which improved with lead-II tracings (EP1: κu202f=u202f0.87, EP2: κu202f=u202f0.83, both pu202f<u202f0.001).nnnCONCLUSIONnRepositioning of the AKM device improves clinician diagnosis of atrial flutter. A lead-II tracing may be considered in high-risk patients to improve detection of atrial flutter.

Smart watches for heart rate assessment in atrial arrhythmias

BACKGROUNDnDespite studies demonstrating the accuracy of smart watches (SW) and wearable heart rate (HR) monitors in sinus rhythm, no data exists regarding their utility in arrhythmias.nnnMETHODSn102 hospitalized patients were evaluated at rest using continuous electrocardiogram (ECG) monitoring with concomitant SW-HR (FitBit, FB, Apple Watch, AW) for 30u202fmin.nnnRESULTSnAcross all devices, 38,616 HR values were recorded. Sinus rhythm cohort demonstrated strong agreement for both devices with a low bias (FB & AW Biasu202f=u202f1 beat). In atrial arrhythmias, AW demonstrated a stronger correlation than FB (AW rsu202f=u202f0.83, FB rsu202f=u202f0.56, both pu202f<u202f0.01) with a lower bias (Bias AWu202f=u202f-5 beats, FBu202f=u202f-18 beats). Atrial flutter demonstrated strongest agreement in both devices with a mean bias <1 beat. However, in AF, there was significant HR underestimation (Bias FBu202f=u202f-28 beats, AW-8 beats) with wide limits of agreement. Despite HR underestimation in AF, when SW recorded HRu202f≥u202f100 in arrhythmias, 98% of values were within ±10-beats of ECG-HR.nnnCONCLUSIONSnSW demonstrate strong agreement for HR estimation in sinus rhythm and atrial flutter but underestimates HR in AF. Tachycardic episodes recorded at rest on a SW may be suggestive of an underlying atrial tachyarrhythmia and warrant further clinical evaluation.nnnCLINICAL TRIAL REGISTRATIONnAustralian New Zealand Clinical Trials Registry (www.anzctr.org.au) ACTRN: 12616001374459.

Utility of photoplethysmography for heart rate estimation among inpatients

The accuracy of photoplethysmography (PPG) for heart rate (HR) estimation in cardiac arrhythmia is unknown. PPG‐HR was evaluated in 112 hospitalised inpatients (cardiac arrhythmias (n = 60), sinus rhythm (n = 52)) using a continuous electrocardiogram monitoring as a reference standard. Strong agreement was observed in sinus rhythm HR < 100 and atrial flutter (bias 1 beat), modest agreement in sinus tachycardia (bias 24 beats) and complete heart block (bias −6 beats) and weak agreement with significant HR underestimation was seen in atrial fibrillation (bias 23 beats). Routine utilisation of PPG for HR estimation may delay early recognition of clinical deterioration in certain arrhythmias and sinus tachycardia.

Takotsubo cardiomyopathy and transient global amnesia: a shared aetiology

Takotsubo cardiomyopathy (TTC) is associated with acute, reversible left ventricular (LV) dysfunction, while transient global amnesia (TGA) is a reversible disorder of the brain characterised by anterograde amnesia. We report an unusual case of TTC occurring concurrently in a patient with TGA, and propose that catecholamine surge induced cerebral venous congestion and cardiotoxicity is the shared aetiology that leads to the concurrent manifestation of these conditions. TTC and TGA are reversible disorders that can occur concurrently in a subset of patients due to a unifying aetiology, catecholamine excess, leading to pathophysiological changes within the brain and the myocardium.