A Case Series of Very Slow Atrioventricular Nodal Reentrant Tachycardia Resembling Junctional Tachycardia

Introduction: The surface EKG of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R’ in V1 and typical heart rates ranging from 150-220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. Methods: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; 1) evidence of dual atrioventricular nodal conduction, 2) tachycardia initiation by atrial drive train with A-H-A response, 3) septal ventriculoatrial (VA) time < 70 ms, and 4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with post pacing interval-tachycardia cycle length (PPI-TCL) > 115ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. Results: We found 11 patients (Age 20-78 years old, 6 female) who met the above-mentioned criteria. The TCL ranged from 560ms to 782ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and PPI-TCL over 115ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. Conclusions: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Evaluation of Low-kVp Low-Volume Iodinated Contrast Protocol for Coronary CT Angiography Using Retrospective ECG Gating

Objective The aim of this study was to evaluate the use of low peak kilovoltage (kVp) low-volume iodinated contrast protocol for performing coronary computed tomography (CT) angiography (CCTA) in patients using retrospective electrocardiogram (ECG) gating. Materials and Methods Hundred prospective patients undergoing CCTA were studied in two groups, A and B, using 70 kilovoltage (kV) and 120 kV protocols with half and standard intravenous volumes of injected iodinated contrast, respectively. All patients had heart rates less than 100 beats/min and body mass index (BMI) less than 31 kg/m2. Both the groups were evaluated for signal-to-noise (S/N) and contrast-to-noise (C/N) ratios along with radiation dose delivered in millisievert (mSv), and for image quality (IQ), on per patient and per segment basis. Results Patients with group A showed statistically reduced radiation dose of 1.86 mSv compared with 6.86 mSv in group B patients. Marked reduction in image noise with statistically improved S/N and C/N ratios in all coronary vessels was seen in group A. S/N ratios in group A were 20.25, 18.68, 19.04, 17.41, and 18.69 for aorta, left main, left anterior descending, right coronary, and left circumflex arteries while they were 13.34, 11.12, 10.96, 9.74, and 8.67 in group B patients. C/N ratios were also higher in all vessels in group A patients, that is, 19.48, 19.48, 19.04, 19.48, and 17.68, compared with group B patients, who had 12.43, 10.03, 9.23, 9.57, and 8.23 ratios (p < 0.0001). No significant difference in IQ per patient and per vessel was seen between both the groups. Discussion Retrospective ECG-gated low-kVp low-volume iodinated contrast protocol provides good diagnostic quality angiograms in patients with BMI up to 31 kg/m2 and with heart rates of less than 100 beats/min with three times reduced radiation dose. The reduced volume of contrast reduces the cost as well as the chance of contrast-induced nephropathy.

Cardiac physiology and metabolic gene expression during late organogenesis among F. heteroclitus embryo families from crosses between pollution-sensitive and -resistant parents

Background The teleost fish Fundulus heteroclitus inhabit estuaries heavily polluted with persistent and bioaccumulative chemicals. While embryos of parents from polluted sites are remarkably resistant to toxic sediment and develop normally, embryos of parents from relatively clean estuaries, when treated with polluted sediment extracts, are developmentally delayed, displaying deformities characteristic of pollution-induced embryotoxicity. To gain insight into parental effects on sensitive and resistant phenotypes during late organogenesis, we established sensitive, resistant, and crossed embryo families using five female and five male parents from relatively clean and predominantly PAH-polluted estuaries each, measured heart rates, and quantified individual embryo expression of 179 metabolic genes. Results Pollution-induced embryotoxicity manifested as morphological deformities, significant developmental delays, and altered cardiac physiology was evident among sensitive embryos resulting from crosses between females and males from relatively clean estuaries. Significantly different heart rates among several geographically unrelated populations of sensitive, resistant, and crossed embryo families during late organogenesis and pre-hatching suggest site-specific adaptive cardiac physiology phenotypes relative to pollution exposure. Metabolic gene expression patterns (32 genes, 17.9%, at p < 0.05; 11 genes, 6.1%, at p < 0.01) among the embryo families indicate maternal pollutant deposition in the eggs and parental effects on gene expression and metabolic alterations. Conclusion Heart rate differences among sensitive, resistant, and crossed embryos is a reliable phenotype for further explorations of adaptive mechanisms. While metabolic gene expression patterns among embryo families are suggestive of parental effects on several differentially expressed genes, a definitive adaptive signature and metabolic cost of resistant phenotypes is unclear and shows unexpected sensitive-resistant crossed embryo expression profiles. Our study highlights physiological and metabolic gene expression differences during a critical embryonic stage among pollution sensitive, resistant, and crossed embryo families, which may contribute to underlying resistance mechanisms observed in natural F. heteroclitus populations living in heavily contaminated estuaries.

Evaluation of Diagnostic Performance of MDCT Coronary Angiography in Comparison with Conventional Coronary Angiography

Background: Coronary artery disease is now becoming increasingly prevalent than before especially in younger age groups. We in the current study tried to evaluate the potential of 128 slice MDCT coronary angiography for the detection of stenotic coronary lesions by comparing the results of computed tomographic coronary angiography to a gold standard set by Conventional coronary angiography. Methods: A total of n=30 patients with clinically suspected Coronary artery disease. They were evaluated with 128 Slice CT Scanner (PHILIPS INGENUITY) and conventional coronary angiography. All patients were examined with a 128 slice MDCT scanner (Philips Ingenuity 128 slice Netherlands) using standard cardiac CT protocol. Gantry rotation time was 400 ms with a half sector acquisition protocol and multisector reconstruction permitting an effective temporal resolution between 50 and 200 ms depending on patient heart rate. Results: In the n=30 Patients included in the study with CCA, the n=450 coronary segments included in the study were found to contain a total number of n=138 stenoses among them non-significant stenoses. The accuracy of MDCT detection of coronary stenoses greater than 50% diameter of vessel lumen is about 94.78. When raising the threshold for stenosis from 50% to 70% of the vessel lumen, so that only hemodynamic relevant stenoses enter the evaluation, the sensitivity decreases from 88%. The MDCT detection in the patient group with heart rates below 60 beats per minute higher values for sensitivity 93% and specificity 97% were observed, compared to sensitivity 87% and specificity 93% of the patient group with heart rates above 60 beats per minute. Conclusion:The present study revealed that a high negative predictive value (98.08%)suggests that 128- Slice MDCT coronary angiography is a good screening modality for evaluation of patients with mild to intermediate-risk factors who might otherwise require invasive angiography.

Measured and perceived exercise intensity during the performance of single-task, cognitive-motor dual-task and exergame training: a transversal study (Preprint)

UNSTRUCTURED The physical and cognitive loads during exergaming may differ from more conventional cognitive-motor dual-task trainings. The aim of this pilot transversal study was to compare exercise intensity during exergame, cognitive-motor dual-task and single-task training sessions. We recruited healthy young adults who carried out one session of each t type of training: exergaming, cognitive-motor dual-tasking and single-tasking. We used a custom-made exergame as support. The sessions lasted 30 minutes, were spaced at least 24 hours, and took place in random order for each group of 4 participants. We used heart rates to assess exercise intensity, and the modified Borg scale to assess their perception of intensity. Sixteen healthy young participants carried out all sessions. There was no difference between the different types of training in mean heart rates (p = 0.3), peak heart rates (p = 0.5) or Borg scale scores (p = 0.4). Our custom-made exergames measured and perceived physical load did not differ between cognitive-motor dual-task and single-task training. As a result, our exergame can be considered as intense as more traditional physical training. Future studies should be conducted in seniors with or without cognitive impairments and should incorporate an assessment of cognitive performance.

Wristbands in Home-Based Rehabilitation—Validation of Heart Rate Measurement

The possibility of using a smartwatch as a rehabilitation tool to monitor patients’ heart rates during exercise has gained the attention of many researchers. This study aimed to evaluate the accuracy and precision of the HR measurement performed by two wrist monitors: the Fitbit Charge 4 and the Xiaomi Mi Band 5. Thirty-one healthy volunteers were asked to perform a stress test on a treadmill. Their heart rates were recorded simultaneously by the wristbands and an electrocardiogram (ECG) at 1 min intervals. The mean absolute error percentage (MAPE), Lin’s concordance correlation coefficient (LCCC), and Bland–Altman analysis were calculated to compare the precision and accuracy of heart rate measurements. The estimated validation criteria were MAPE < 10% and LCCC < 0.8. The overall MAPE and LCCC of the Fitbit were 10.19% (±11.79%) and 0.753 (95% CI: 0.717–0.785), respectively. The MAPE and LCCC of the Xiaomi were 6.89% (±9.75) and 0.903 (0.886–0.917), respectively. The precision and accuracy of both devices decreased with the increased exercise intensity. The accuracy of wearable wrist-worn heart rate monitors varies and depends on the intensity of training. Therefore, the decision to use such a device as a heart rate monitor during in-home rehabilitation should be made with caution.

Effects of unpleasant emotional exposure on the state anxiety and heart rate in healthy women: a pilot study

Considering that exposure to unpleasant pictures taken from the International Affective Pictures System (IAPS) has a more significant impact on anxiety than exposure to pleasant and neutral pictures, we investigated changes in state anxiety levels and heart rate responses in healthy women following exposure to three blocks of unpleasant pictures from the IAPS. Thirty-seven healthy women visited the lab three times, separated by a gap of 24–72 hours. Anxiety levels were assessed using the State Anxiety Inventory before and after participants viewed the blocks of unpleasant IAPS pictures, while the heart rate was continuously monitored throughout each session by a heart rate monitor. We found extreme evidence (BF10 = 7.53*108) for the changes in the participants’ state anxiety after viewing IAPS unpleasant pictures, although there was ambiguous evidence (BF01 = 2.642) favoring similar changes in state anxiety and ratings of pleasure (BF01 = 1.567), arousal (BF01 = 2.609), and dominance (BF01 = 1.954) between the three blocks of unpleasant pictures used. Moreover, we found moderate evidence (BF01 = 7.449) favoring similar mean heart rates between the three blocks of unpleasant pictures. These findings reveal that exposure to unpleasant pictures can act as an anxiogenic stimulus used to induce experimental anxiety.

AN OBSERVATIONAL STUDY ON THE ACCURACY OF HEART RATE READINGS BETWEEN SMART WATCHES AND A HAND HELD VITAL SIGN MONITOR IN STATIC AND DYNAMIC MOTIONS ON A HEALTHY YOUNG ADULT POPULATION

There are various devices and applications available in the market that can be used to measure heart rates. These are becoming increasingly popular. Amongst these include the Apple watch, the Xiaomi MI Band and using the Thermal Application (T.A.P.) software (used through a Smartphone). In clinical practice and research, usually the E.C.G. Is used to measure the heart rates, (apart from manually counting the beats by palpation). The study will determine the accuracy of using the available devices in the market (previously mentioned), and also determine if they can be used on patients or subjects while sitting and walking, in clinical practice and researches. Method: It will be a comparative observational study. 50 students, selected as per the inclusion and exclusion criteria from Datta Meghe Institute of Medical Sciences will be the subjects of this study. Their heart rates will be monitored with the three devices, and compared with the readings from an E.C.G. It will be done as per Bruce protocol during walking, and in static sitting. The accuracy of the devices will be determined by analyzing the results acquired. The devices are: Apple watch, Xiaomi MI band, and a smart Phone with Thermal Application (T.A.P.) software installed. The successful completion of the study will determine which of the devices show the most accurate heart rate readings, in what positions of a patient (sitting or walking) it would be acceptable to use these devices (in terms of accuracy) in the case where an E.C.G. is not available, or at a time of urgency. The study will also show if it would be appropriate to use these devices in clinical practice and research studies.

Pediatric tizanidine toxicity reversed with naloxone: a case report

Background Tizanidine, an α-2 adrenoceptor agonist, is widely prescribed for the management of spasticity in adults. Case reports on pediatric tizanidine overdose are limited. Here, we report a case of pediatric tizanidine toxicity that was reversed with naloxone. Case presentation A 3-year-old male presented to the emergency department with lethargy, bradycardia, and bradypnea after accidental ingestion of multiple tizanidine tablets. Improvements in the level of consciousness and respiratory and heart rates were observed after two intravenous administrations of naloxone at a dose of 0.05 and 0.1 mg/kg, respectively. Conclusions This case report provides further evidence regarding the use of naloxone as a viable antidote for centrally acting α-2 receptor agonists and presents additional epidemiologic data on childhood tizanidine poisoning.