Supraventricular tachycardias: proposal of a diagnostic algorithm for the narrow complex tachycardias

Analysis of ST segment depression in supraventricular tachycardia and its relationship with underlying mechanism

BACKGROUND

Electrocardiographic diagnosis of causes of supraventricular tachycardia (SVT) is sometimes difficult and application of routine algorithms can lead to misdiagnosis in as many as 37 % of patients. ST segment depression may be useful in diagnosing the nature of SVT.

METHODS

We reviewed surface electrocardiogram (ECG) characteristics of 300 patients having SVT with 1:1 AV relationship and correlated findings with electrophysiology study (EPS) findings. Final diagnosis of AVNRT (Atrioventricular nodal reentrant tachycardia), Orthodromic AVRT (atrioventricular reentrant tachycardia) and atrial tachycardia (AT) was correlated with ECG parameters like heart rate, ST segment depressions and QRS morphology.

RESULTS

Out of 300 patients, majority patients included in study, were having AVNRT or AVRT. ST depression predicted AVRT if the ST depression was ≥ 2 mm (overall sensitivity of 38.3 % and specificity of 93.8 % to predict AVRT) and was downsloping in morphology (sensitivity of 36.9 % and specificity of 94.7 % to predict AVRT). At heart rates ≥214 beats per minute (bpm) as measured by 7 small squares of ECG at 25 mm/s, downsloping ST depression ≥2 mm had a sensitivity 37.9 % of and specificity of 89.2 % to predict AVRT. At heart rate <214 bpm, downsloping ST depression ≥2 mm had sensitivity of 37.2 % and specificity of 96.5 % to predict AVRT. Downsloping ST depression of ≥2 mm helps to differentiate AVNRT from AVRT.

CONCLUSION

A downsloping ST segment depression ≥2 mm predicted SVT being an AVRT and can be used as a useful criteria in diagnosing the tachycardia.

Diagnosis and management of patients who present with narrow complex tachycardia in the emergency department

INTRODUCTION

While narrow complex tachycardia (NCT) is a common presentation to the emergency department (ED), little is known about its incidence in the ED or about emergency physician expertise in its diagnosis and management. We sought to compare cases of NCT due to primary arrhythmias to those with a rapid heart rate secondary to a medical issue, as well as to determine the accuracy of ED physician diagnosis and appropriateness of treatment.

METHODS

We conducted a health records review at a large academic hospital ED staffed by 95 physicians and included consecutive adult patients over 7 months (2020-2021) with NCT (heart rate ≥ 130 bpm and QRS < 120 ms). Cases were reviewed for accuracy of ECG diagnosis and for correctness of treatment as per guidelines by an adjudication committee.

RESULTS

We identified 310 ED visits (0.8% of all ED visits), mean age 65.1 years, 52.6% female. Primary arrhythmias accounted for 54.8%. ED physicians correctly interpreted 86.6% of ECGs. The most common arrhythmias and accuracy of ED physician ECG interpretation were atrial fibrillation 44.5% (95.1%), sinus tachycardia 24.2% (90.5%), atrial flutter 15.8% (61.5%), and supraventricular tachycardia (SVT) 12.9% (81.6%). Treatments were judged optimal in 96.5% of primary NCT and 99.3% in secondary NCT. Treatments were suboptimal for failure to reduce heart rate < 100 bpm prior to discharge in 2.1% of primary cases and failure to treat underlying cause in 0.7% of secondary cases.

CONCLUSION

NCT was found in 0.8% of all ED visits, with more being primary NCT. ED physicians correctly interpreted 86.6% of ECGs but had difficulty differentiating atrial flutter and SVT. They implemented appropriate care in most cases but sometimes failed to adequately control heart rate or to treat the underlying condition, suggesting opportunities to improve care of NCT in the ED.

Alice in Wonderland Syndrome-Like Seizure and Refractory Supraventricular Tachycardia

Alice in Wonderland syndrome (AIWS) is a rarely curious visual perceptual disorder which has been associated with diverse neurologic and psychiatric problems. It may be a manifestation in migraine, epileptic seizures, encephalitis, other brain lesions, medication-related side effects, schizophrenia, and depressive disorders. Principal character of AIWS is the disproportion between the external world and the self-image in which micropsia (objects appear smaller), macropsia (objects appear larger), and teleopsia (objects appear further away) are frequently reported. The cases of temporal lobe epilepsy may present with complex visual auras of visual distortions (e.g., micropsia and macropsia) like AIWS. We report an unusual case of an elderly man who presented with AIWS, focal impaired awareness seizures, ictal tachyarrhythmia, multiple episodes of transient visual disturbances of macropsia and transient loss of consciousness. During those symptoms, telemetry showed self-limited supraventricular tachycardia several times which could not be regulated with heart rate-controlled medication. The electroencephalography was later tested and showed rhythmic theta activity over the right cerebral hemisphere. He was treated with levetiracetam, and all his symptoms and tachyarrhythmias were gradually resolved thereafter. Refractory response to treatment would remind the physicians to reassess for the correct diagnosis.

Cost-effective vital signs monitoring system for COVID-19 patients in smart hospital

The lack of staffing during COVID-19 pandemic drives hospitals to expand their facilities in non-traditional settings to include centralized communication systems to monitor the vital signs of patients and predictive models to identify their health conditions. In this research, we have developed a microcontroller-based wireless vital signs monitoring system, which is able to measure the body temperature, heart rate, blood oxygen level, respiratory rate and Electrocardiogram of the patients. We managed to obtain a reliable but more affordable vital signs monitor with high mobility that can be implemented in large hospitals. The system satisfies the design considerations of medical centers in terms of size, cost, power consumption and simplicity in implementation. The developed system consists of a set of wearable sensor nodes, wireless communications infrastructure with multiple communications techniques to carry vital data from the patients to the management system that handles the patient’s medical data, and a graphical user interface with a control system that enables the hospital staff to observe the status of all the patients and take the appropriate actions. The system was implemented using 40 sensor nodes, 4 distribution points and one gateway covering a hospital area of approximately 2500 m². The system was tested and the measured percentage of lost packets is found to be less than 3.3% of those sent. During transmission, the current measured from the sensor node was 10.5 mA with a 3.3 V input voltage, which prolonged the operating time of the battery used.

A new score model to predict the inducibility of supraventricular tachycardia in patients with palpitation without documented electrocardiography

OBJECTIVE

Although electrophysiological study (EPS) is one of the most useful diagnostic approaches to detect the cardiac origin of palpitations, there is no clear indication for EPS in patients with palpitation in the absence of documented supraventricular tachycardia (SVT). In this study, we aimed to create a new SVT score model to detect the requirement of EPS in patients with palpitation without documented tachycardia.

METHODS

A total of 154 patients with palpitation were included in this study. To create the SVT score, we considered four main criteria with their subunits. They were severity, frequency, duration, and termination of the symptoms. EPS was performed on all the patients after their scoring assessment.

RESULTS

Median SVT score of induced tachycardia and non-induced patients was determined as 10 and 6 points, respectively; and it was found to be statistically significant; p<0.001. The cut-off value for inducibility was found to be 7.5 points through receiver operating characteristic curve analysis, (94.9% sensitivity, 92.1% specificity), and the area under the curve was determined to be 97.2 (94.8-99.5, p<0.001).

CONCLUSION

According to our new SVT score model, ≥8 points strongly correlates with the inducibility of SVT during EPS.

A novel wavelet-based filtering strategy to remove powerline interference from electrocardiograms with atrial fibrillation

OBJECTIVE

The electrocardiogram (ECG) is currently the most widely used recording to diagnose cardiac disorders, including the most common supraventricular arrhythmia, such as atrial fibrillation (AF). However, different types of electrical disturbances, in which power-line interference (PLI) is a major problem, can mask and distort the original ECG morphology. This is a significant issue in the context of AF, because accurate characterization of fibrillatory waves (f-waves) is unavoidably required to improve current knowledge about its mechanisms. This work introduces a new algorithm able to reduce high levels of PLI and preserve, simultaneously, the original ECG morphology.

APPROACH

The method is based on stationary wavelet transform shrinking and makes use of a new thresholding function designed to work successfully in a wide variety of scenarios. In fact, it has been validated in a general context with 48 ECG recordings obtained from pathological and non-pathological conditions, as well as in the particular context of AF, where 380 synthesized and 20 long-term real ECG recordings were analyzed.

MAIN RESULTS

In both situations, the algorithm has reported a notably better performance than common methods designed for the same purpose. Moreover, its effectiveness has proven to be optimal for dealing with ECG recordings affected by AF, since f-waves remained almost intact after removing very high levels of noise.

SIGNIFICANCE

The proposed algorithm may facilitate a reliable characterization of the f-waves, preventing them from not being masked by the PLI nor distorted by an unsuitable filtering applied to ECG recordings with AF.

Supraventricular Tachycardia and Tricuspid Regurgitation in the Setting of Misplaced Implantable Port Catheter Tip

We present the case of a 31-year-old female with a past medical history of B-cell leukemia, on maintenance chemotherapy administered via centrally placed implantable catheter port, who presented to the emergency room with fever, chills, and generalized body pain of one day's duration. After initial workup, the patient was admitted to the intensive care unit and managed for severe sepsis. The patient was found to have a new-onset 3/6 holosystolic murmur at the left lower sternal border. Furthermore, she developed an episode of supraventricular tachycardia that responded to adenosine. Transthoracic echocardiogram revealed severe tricuspid regurgitation but without valvular vegetation. Transesophageal echocardiogram further confirmed the absence of vegetation, in addition to visualizing the tip of the catheter tip in the right atrium and interfering with coaptation of the tricuspid valve. It was postulated that the severe tricuspid regurgitation and supraventricular tachycardia were caused by the catheter tip malposition. The catheter was subsequently removed. The patient’s acute condition resolved and she was referred to cardiothoracic surgery for valvular surgery.

Symptoms in supraventricular tachycardia: Is it simply a manifestation of increased heart rate?

A significant proportion of patients in clinical practice may not have ECG recordings of the index tachycardia (non-documented SVT), or only have recordings of limited diagnostic value. Despite the highly specified symptomatic and ECG diagnostic criteria, diagnosis and referral for ablation treatment is not always straightforward. Although ECG based diagnostic or treatment algorithms have been well defined in literature, we need a symptom based diagnostic algorithm or scoring system in patients with suspected supraventricular arrhythmia. Individual approaches with a high suspicion index and concerning the paroxysmal nature and post attack symptoms would help us to identify patients suffering from SVT in complex cases.

Electrocardiographic diagnosis of atrial tachycardia: classification, P-wave morphology, and differential diagnosis with other supraventricular tachycardias

Atrial tachycardia is defined as a regular atrial activation from atrial areas with centrifugal spread, caused by enhanced automaticity, triggered activity or microreentry. New ECG classification differentiates between focal and macroreentrant atrial tachycardia. Macroreentrant atrial tachycardias include typical atrial flutter and other well characterized macroreentrant circuits in right and left atrium. Typical atrial flutter has been described as counterclockwise reentry within right atrial and it presents a characteristic ECG "sawtooth" pattern on the inferior leads. The foci responsible for focal atrial tachycardia do not occur randomly throughout the atria but tend to cluster at characteristic anatomical locations. The surface ECG is a very helpful tool in directing mapping to particular areas of interest. Atrial tachycardia should be differentiated from other supraventricular tachycardias. We propose a diagnostic algorithm in order to help the physician to discriminate among those. Holter analysis could offer further details to differentiate between atrial tachycardia and another supraventricular tachycardia. However, if the diagnosis is uncertain, it is possible to utilize vagal maneuvers or adenosine administration. In conclusion, in spite of well-known limits, a good interpretation of ECG is very important and it could help the physician to manage and to treat correctly patients with atrial tachycardia.

Epidemiology, prevention, and treatment of new-onset atrial fibrillation in critically ill: a systematic review

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia in the ICU. The aim of this review is to summarize relevant information on new-onset AF in non-cardiac critical illness with respect to epidemiology, prevention, and treatment.

METHODS

We conducted a PubMed search in June 2014 and included studies describing the epidemiology, prevention, and treatment of new-onset AF and atrial flutter during ICU stay in non-cardiac adult patients. Selected studies were divided into the three categories according to the extracted information. The methodological quality of selected studies was described according to the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

We identified 1,132 citations, and after full-text-level selection, we included 10 studies on etiology/outcome and five studies on treatment. There was no study related to prevention. Overall quality of evidence was mostly low or very low due to their observational study designs, small sample sizes, flawed diagnosis of new-onset AF, and the absence of mortality evaluation. The incidence of new-onset AF varied from 4.5% to 15.0%, excluding exceptional cases (e.g., septic shock). Severity scores of patients with new-onset AF were higher than those without new-onset AF in eight studies, in four of which the difference was statistically significant. Five studies reported risk factors for new-onset AF, all of which used multivariate analyses to extract risk factors. Multiple risk factors are reported, e.g., advanced age, the white race, severity scores, organ failures, and sepsis. Hospital mortality in new-onset AF patients was higher than that of patients without AF in all studies, four of which found statistical significance. Among the five studies on treatment, only one study was randomized controlled, and various interventions were studied.

CONCLUSIONS

New-onset AF occurred in 5%-15% of the non-cardiac critically ill patients. Patients with new-onset AF had poor outcomes compared with those without AF. Despite the high incidence of new-onset AF in the general ICU population, currently available information for AF, especially for management (prevention, treatment, and anticoagulation), is quite limited. Further research is needed to improve our understanding of new-onset AF in critically ill patients.

Smart multi-level tool for remote patient monitoring based on a wireless sensor network and mobile augmented reality

Technological innovations in the field of disease prevention and maintenance of patient health have enabled the evolution of fields such as monitoring systems. One of the main advances is the development of real-time monitors that use intelligent and wireless communication technology. In this paper, a system is presented for the remote monitoring of the body temperature and heart rate of a patient by means of a wireless sensor network (WSN) and mobile augmented reality (MAR). The combination of a WSN and MAR provides a novel alternative to remotely measure body temperature and heart rate in real time during patient care. The system is composed of (1) hardware such as Arduino microcontrollers (in the patient nodes), personal computers (for the nurse server), smartphones (for the mobile nurse monitor and the virtual patient file) and sensors (to measure body temperature and heart rate), (2) a network layer using WiFly technology, and (3) software such as LabView, Android SDK, and DroidAR. The results obtained from tests show that the system can perform effectively within a range of 20 m and requires ten minutes to stabilize the temperature sensor to detect hyperthermia, hypothermia or normal body temperature conditions. Additionally, the heart rate sensor can detect conditions of tachycardia and bradycardia.