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The Israel Medical Association Journal... Apr 2022Heart rate disorders and in particular sinus arrhythmias are known to accompany viral infections. Sinus tachycardia is prevalent in the presence of increased body...
Heart rate disorders and in particular sinus arrhythmias are known to accompany viral infections. Sinus tachycardia is prevalent in the presence of increased body temperature and respiratory rate. However, bradycardia has also been described for centuries to complicate viral illnesses.
Topics: Bradycardia; COVID-19; Electrocardiography; Heart Rate; Humans
PubMed: 35415977
DOI: No ID Found -
Proceedings of the National Academy of... Dec 2019The biology of the blue whale has long fascinated physiologists because of the animal's extreme size. Despite high energetic demands from a large body, low mass-specific...
The biology of the blue whale has long fascinated physiologists because of the animal's extreme size. Despite high energetic demands from a large body, low mass-specific metabolic rates are likely powered by low heart rates. Diving bradycardia should slow blood oxygen depletion and enhance dive time available for foraging at depth. However, blue whales exhibit a high-cost feeding mechanism, lunge feeding, whereby large volumes of prey-laden water are intermittently engulfed and filtered during dives. This paradox of such a large, slowly beating heart and the high cost of lunge feeding represents a unique test of our understanding of cardiac function, hemodynamics, and physiological limits to body size. Here, we used an electrocardiogram (ECG)-depth recorder tag to measure blue whale heart rates during foraging dives as deep as 184 m and as long as 16.5 min. Heart rates during dives were typically 4 to 8 beats min (bpm) and as low as 2 bpm, while after-dive surface heart rates were 25 to 37 bpm, near the estimated maximum heart rate possible. Despite extreme bradycardia, we recorded a 2.5-fold increase above diving heart rate minima during the powered ascent phase of feeding lunges followed by a gradual decrease of heart rate during the prolonged glide as engulfed water is filtered. These heart rate dynamics explain the unique hemodynamic design in rorqual whales consisting of a large-diameter, highly compliant, elastic aortic arch that allows the aorta to accommodate blood ejected by the heart and maintain blood flow during the long and variable pauses between heartbeats.
Topics: Animals; Balaenoptera; Bradycardia; Electrocardiography; Feeding Behavior; Heart; Heart Rate; Oxygen; Tachycardia
PubMed: 31767746
DOI: 10.1073/pnas.1914273116 -
Journal of Medical Case Reports Jun 2022Systemic sclerosis is a multisystemic character autoimmune disease. It is characterized by vascular dysfunction and progressive fibrosis affecting mainly the skin but...
BACKGROUND
Systemic sclerosis is a multisystemic character autoimmune disease. It is characterized by vascular dysfunction and progressive fibrosis affecting mainly the skin but also different internal organs. All heart structures are commonly affected, including the pericardium, myocardium, and conduction system. However, tachycardia-bradycardia syndrome is not common in the literature as a cardiac complication of systemic sclerosis. Case presentation We report a case of tachycardia-bradycardia syndrome in a 46-year-old Moroccan woman followed for systemic sclerosis with cutaneous, vascular, and articular manifestations. The diagnosis was based mainly on patient-reported symptoms and electrocardiogram data. A permanent pacemaker was implanted, allowing the introduction of beta-blockers with good outcomes.
CONCLUSIONS
This case aims to show that even minor electrocardiogram abnormalities should be monitored in this group of patients, preferably by 24-hour ambulatory electrocardiogram because they could be a good indicator of the activity and progression of cardiac fibrosis.
Topics: Bradycardia; Electrocardiography; Female; Humans; Middle Aged; Scleroderma, Systemic; Sick Sinus Syndrome; Tachycardia
PubMed: 35729641
DOI: 10.1186/s13256-022-03462-z -
Clinical Cardiology May 2021Insertable cardiac monitors (ICMs) improve diagnostic yield in patients with unexplained syncope. The most of cardiac syncope is arrhythmic causes include paroxysmal...
BACKGROUND
Insertable cardiac monitors (ICMs) improve diagnostic yield in patients with unexplained syncope. The most of cardiac syncope is arrhythmic causes include paroxysmal bradycardia and supraventricular tachycardia (SVT) in patients with unexplained syncope receiving ICM. Predictors for bradycardia and SVT that necessitate therapy in patients with unexplained syncope are not well known.
HYPOTHESIS
This study aimed to investigate predictors of bradycardia and SVT necessitating therapy in patients with unexplained syncope receiving ICMs.
METHODS
We retrospectively reviewed medical records of consecutive patients who received ICMs to monitor unexplained syncope. We performed Cox's stepwise logistic regression analysis to identify significant independent predictors for bradycardia and SVT.
RESULTS
One hundred thirty-two patients received ICMs to monitor unexplained syncope. During the 17-month follow-up period, 19 patients (14%) needed pacemaker therapy for bradycardia; 8 patients (6%) received catheter ablation for SVT. The total estimated diagnostic rates were 34% and 48% at 1 and 2 years, respectively. Stepwise logistic regression analysis indicated that syncope during effort (odds ratio [OR] = 3.41; 95% confidence interval [CI], 1.21 to 9.6; p = .02) was an independent predictor for bradycardia. Palpitation before syncope (OR = 9.46; 95% CI, 1.78 to 50.10; p = .008) and history of atrial fibrillation (OR = 10.1; 95% CI, 1.96 to 52.45; p = .006) were identified as significant independent predictors for SVT.
CONCLUSION
Syncope during effort, and palpitations or history of atrial fibrillation were independent predictors for bradycardia and for SVT. ICMs are useful devices for diagnosing unexplained syncope.
Topics: Aged; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Atrial Fibrillation; Bradycardia; Electrocardiography, Ambulatory; Humans; Male; Retrospective Studies; Syncope; Tachycardia, Supraventricular
PubMed: 33724499
DOI: 10.1002/clc.23594 -
Southern Medical Journal Jul 2021To assess the clinical characteristics and clinical outcomes of bradycardic patients with coronavirus disease 2019 (COVID-19) pneumonia.
OBJECTIVE
To assess the clinical characteristics and clinical outcomes of bradycardic patients with coronavirus disease 2019 (COVID-19) pneumonia.
METHODS
The electronic medical records of 221 consecutive patients hospitalized for COVID-19 pneumonia between June and September 2020 were retrospectively reviewed. Patient characteristics, electrocardiographic data, and clinical and laboratory information were retrospectively collected. Patients not treated with drugs that blunt chronotropic response (nodal) were analyzed separately.
RESULTS
Only patients whose heart rate was <60 beats per minute (bpm) (136/221, 61.5%) were included. Serial electrocardiography revealed that most patients (130/137, 97.7%) remained in sinus rhythm. The heart rate was between 50 and 59 bpm in 75% of the patients, while 18.4% were in the 40 to 49 bpm range, and 6.6% were <40 bpm. Medians for development of bradycardia after swab polymerase chain reaction positivity and duration of bradycardia were 41 hours and 5 days, respectively. Bradycardia resolved in 81 patients (59.6%). There were no statistically significant differences in outcomes according to degree of bradycardia (<50 vs 50-59, all ≥ 0.073). No significant differences were noted for the overall cohort when comparing COVID-19 treatments according to resolution of bradycardia; however, when considering only the patients who were not receiving a nodal agent or antiarrhythmic, treatment with lenzilumab was more common in patients with resolution of bradycardia than patients without resolution of bradycardia (12.2% vs 0.0%, = 0.030).
CONCLUSIONS
Sinus bradycardia occurs frequently in patients with severe COVID-19, but the degree of bradycardia does not correlate with clinical outcomes. Lenzilumab may be associated with the resolution of bradycardia.
Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Bradycardia; COVID-19; Electrocardiography; Female; Hospitalization; Humans; Male; Middle Aged; Retrospective Studies; Young Adult
PubMed: 34215897
DOI: 10.14423/SMJ.0000000000001269 -
Journal of the American Veterinary... Nov 2019
Topics: Animals; Bradycardia; Cat Diseases; Cats; Electrocardiography; Male; Renal Insufficiency
PubMed: 31617802
DOI: 10.2460/javma.255.9.1013 -
Physiological Reports Jan 2021The presence of bradycardic arrhythmias during volitional apnea at altitude may be caused by chemoreflex activation/sensitization. We investigated whether...
The presence of bradycardic arrhythmias during volitional apnea at altitude may be caused by chemoreflex activation/sensitization. We investigated whether bradyarrhythmic episodes became prevalent in apnea following short-term hypoxia exposure. Electrocardiograms (ECG; lead II) were collected from 22 low-altitude residents (F = 12; age=25 ± 5 years) at 671 m. Participants were exposed to normobaric hypoxia (SpO ~79 ± 3%) over a 5-h period. ECG rhythms were assessed during both free-breathing and maximal volitional end-expiratory and end-inspiratory apnea at baseline during normoxia and hypoxia exposure (20 min [AHX]; 5 h [HX5]). Free-breathing HR became elevated at AHX (78 ± 10 bpm; p < 0.0001) and HX5 (80 ± 12 bpm; p < 0.0001) compared to normoxia (68 ± 10 bpm), whereas apnea caused significant bradycardia at AHX (nadir end-expiratory -17 ± 14 bpm; p < 0.001) and HX5 (nadir end-expiratory -19 ± 15 bpm; p < 0.001), but not during normoxia (nadir end-expiratory -4 ± 13 bpm), with no difference in bradycardia responses between apneas at AHX and HX5. Conduction abnormalities were noted in five participants during normoxia (Premature Ventricular Contraction, Sinus Pause, Junctional Rhythm, Atrial Foci), which remained unchanged during apnea at AHX and HX5 (Premature Ventricular Contraction, Premature Atrial Contraction, Sinus Pause). End-inspiratory apneas were overall longer across conditions (normoxia p < 0.05; AHX p < 0.01; HX5 p < 0.001), with comparable HR responses to end-expiratory and fewer occurrences of arrhythmia. While short-term hypoxia is sufficient to elicit bradycardia during apnea, the occurrence of arrhythmias in response to apnea was not affected. These findings indicate that previously observed bradyarrhythmic events in untrained individuals at altitude only become prevalent following chronic hypoxia specificlly.
Topics: Adult; Apnea; Arrhythmias, Cardiac; Bradycardia; Canada; Chemoreceptor Cells; Female; Heart Conduction System; Heart Rate; Humans; Hypoxia; Male
PubMed: 33426815
DOI: 10.14814/phy2.14703 -
Arquivos Brasileiros de Cardiologia Jul 2019
Topics: Bradycardia; Catheter Ablation; Ganglia, Autonomic; Humans; Severity of Illness Index; Syncope, Vasovagal
PubMed: 31314822
DOI: 10.5935/abc.20190107 -
Pediatric Research Nov 2019Preterm very low birth weight (VLBW) infants experience physiologic maturation and transitions off therapies from 32 to 35 weeks postmenstrual age (PMA), which may...
BACKGROUND
Preterm very low birth weight (VLBW) infants experience physiologic maturation and transitions off therapies from 32 to 35 weeks postmenstrual age (PMA), which may impact episodic bradycardia and oxygen desaturation. We sought to characterize bradycardias and desaturations from 32 to 35 weeks PMA and test whether events at 32 weeks PMA are associated with NICU length of stay.
METHODS
For 265 VLBW infants from 32 to 35 weeks PMA, we quantified the number and duration of bradycardias (HR <100 for ≥4 s) and desaturations (SpO <80% for ≥10 s) and compared events around discontinuation of CPAP, caffeine, and supplemental oxygen. We modeled associations between clinical variables, bradycardias and desaturations at 32 weeks PMA, and discharge PMA.
RESULTS
Desaturations decreased from 60 to 41 per day at 32 and 35 weeks, respectively (p < 0.01). Duration of desaturations and number and duration of bradycardias decreased to a smaller extent (p < 0.05), and there was a non-significant trend toward increased desaturations after stopping CPAP and caffeine. Controlling for clinical variables, longer duration of bradycardias and desaturations at 32 weeks PMA was associated with later discharge PMA.
CONCLUSION
Delayed recovery from bradycardias and desaturations at 32 weeks PMA, perhaps reflecting less physiologic resilience, is associated with prolonged NICU stay for VLBW infants.
Topics: Bradycardia; Electrocardiography; Female; Humans; Hypoxia; Infant, Newborn; Infant, Very Low Birth Weight; Intensive Care Units, Neonatal; Length of Stay; Male; Outcome Assessment, Health Care
PubMed: 31272102
DOI: 10.1038/s41390-019-0488-3 -
Clinical Cardiology Dec 2010The authors have no funding, financial relationships, or conflicts of interest to disclose.
The authors have no funding, financial relationships, or conflicts of interest to disclose.
Topics: Aged, 80 and over; Atrial Fibrillation; Bradycardia; Electrocardiography; Female; Heart Conduction System; Humans; Hypothermia; Respiratory Rate; Rewarming; Severity of Illness Index; Treatment Outcome
PubMed: 21184553
DOI: 10.1002/clc.20380