Risk factors for tachycardia-induced cardiomyopathy due to atrial fibrillation.

BACKGROUND: Tachycardia-induced cardiomyopathy (TIC) is a reversible cardiomyopathy with ventricular dysfunction caused by tachyarrhythmias. Notably, atrial fibrillation (AF) is the most common causal arrhythmia leading to TIC. However, the risk factors for the development of TIC due to AF remain unclear. This study aimed to identify the associated factors of TIC due to AF. METHODS: Persistent AF patients with heart rate (HR) ≥100 beats per minute who underwent initial catheter ablation were enrolled in this study. TIC was diagnosed as left ventricular ejection fraction (LVEF) < 50% during AF rhythm, which was recovered after the restoration of sinus rhythm. Non-TIC was defined as LVEF ≥ 50% despite AF rhythm. The patient backgrounds were compared between the TIC group and the non-TIC group to reveal the contributing factors of TIC. RESULTS: The TIC group comprised 57 patients, while the non-TIC group consisted of 101 patients. The TIC group was younger than the non-TIC group (median 64 vs. 70, p = 0.006). Male sex was more frequent in the TIC group than the non-TIC group (82.5% vs. 58.4%, p = 0.003). HR was higher in the TIC group than in the non-TIC group (median 130 bpm vs. 111 bpm, p < 0.001). The number of smokers was significantly higher in the TIC group than in the non-TIC group (p < 0.001). Multivariable analysis demonstrated that higher HR (odds ratio [OR]: 1.74; 95% confidence interval [CI]: 1.37-2.21; p < 0.001) and current smokers (OR: 5.27; 95% CI: 1.60-17.4; p = 0.006) were the independent factors leading to TIC. CONCLUSION: Higher HR and current smokers were independent risk factors for the development of TIC due to AF.

The predictive value of heart rate in determining clinical course after a bupropion overdose.

INTRODUCTION: Bupropion is a popular antidepressant due to its favorable side effect profile and indications for smoking cessation and weight loss. Due to the possibility of delayed onset seizure and other adverse outcomes after bupropion overdose, patients are often observed for periods of 12-24 hours following suspected ingestion. Tachycardia is a clinical predictor that holds promise in differentiating cases at risk for seizures from low-risk cases that do not require prolonged observation. This study assessed whether heart rate within the first eight hours of presentation can identify cases that do not require extended observation. METHODS: This is a retrospective cohort study of all supra-therapeutic bupropion cases from two hospital systems between 2010 and 2022. RESULTS: Data from 216 charts were included. Seizures, hypotension, and dysrhythmias occurred in 19 percent (n = 41), 1.4 percent (n = 3), 0.9 percent (n = 2) respectively. One patient died. Delayed adverse effects were rare (n = 4); they occurred from 14 hours to 28 hours post-ingestion. Maximum heart rate in eight hours was associated with a risk of adverse outcomes. (odds ratio, 1.07; 95 percent confidence interval: 1.05 to 1.09; P < 0.001). An eight hour maximum heart rate threshold of 104 beats/minute had a negative predictive value of 100 percent (95 percent confidence interval: 96.7 percent to 100 percent) for the occurrence of delayed adverse effects. All patients with delayed effects had tachycardia within five hours of emergency department arrival. DISCUSSION: Delayed adverse outcomes of seizures, hypotension, dysrhythmia, and death were uncommon in this cohort. Heart rate during the first eight hours of observation performs reliably as a screening test to identify patients at low risk for delayed adverse outcomes. This study is limited by its retrospective nature, the inability to ascertain time of ingestion for most cases and the lack of confirmatory laboratory testing. CONCLUSION: This study supports the use of an eight hour observation period when there are no other clinical signs of toxicity to warrant admission and if no co-ingestion or administration of substances that mask tachycardia are present.

Ivabradine restores tonic cardiovascular autonomic control and reduces tachycardia, hypertension and left ventricular inflammation in post-weaning protein malnourished rats.

Malnutrition results in autonomic imbalance and heart hypertrophy. Overexpression of hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in the left ventricles (LV) is linked to hypertrophied hearts and abnormal myocardium automaticity. Given that ivabradine (IVA) has emerging pleiotropic effects, in addition to the widely known bradycardic response, this study evaluated if IVA treatment could repair the autonomic control and cardiac damages in malnourished rats. AIM: Assess the impact of IVA on tonic cardiovascular autonomic control and its relationship with hemodynamics regulation, LV inflammation, and HCN gene expression in post-weaning protein malnutrition condition. MAIN METHODS: After weaning, male rats were divided into control (CG; 22 % protein) and malnourished (MG; 6 % protein) groups. At 35 days, groups were subdivided into CG-PBS, CG-IVA, MG-PBS and MG-IVA (PBS 1 ml/kg or IVA 1 mg/kg) received during 8 days. We performed jugular vein cannulation and electrode implant for drug delivery and ECG registration to assess tonic cardiovascular autonomic control; femoral cannulation for blood pressure (BP) and heart rate (HR) assessment; and LV collection to evaluate ventricular remodeling and HCN gene expression investigation. KEY FINDINGS: Malnutrition induced BP and HR increases, sympathetic system dominance, and LV remodeling without affecting HCN gene expression. IVA reversed the cardiovascular autonomic imbalance; prevented hypertension and tachycardia; and inhibited the LV inflammatory process and fiber thickening caused by malnutrition. SIGNIFICANCE: Our findings suggest that ivabradine protects against malnutrition-mediated cardiovascular damage. Moreover, our results propose these effects were not attributed to HCN expression changes, but rather to IVA pleiotropic effects on autonomic control and inflammation.

Adeno-associated virus-mediated gene therapy for cardiac tachyarrhythmia: A systematic review and meta-analysis.

Cardiac tachyarrhythmia presents a significant health care challenge, causing notable morbidity and mortality. Conventional treatments have limitations and potential risks, resulting in an elevated disease burden. Adeno-associated virus (AAV)-mediated gene therapy holds promise as a potential future treatment option. Therefore, we aimed to provide a measured overview of the latest developments in this rapidly growing field. PubMed and Embase databases were searched up to January 2024. Studies that employed AAV as a vector for delivery of therapeutic agents to treat cardiac tachyarrhythmia were included. Of the 26 studies included, 20 published in the last 5 years. There were 22 novel molecular targets identified. More than 80% of the included studies employed small-animal models or used AAV9. In atrial fibrillation preclinical studies, AAV-mediated gene therapy reduced atrial fibrillation inducibility by 81% (odds ratio, 0.19 [0.08-0.45]; P < .01). Similarly, for acquired and inherited ventricular arrhythmia, animal models receiving gene therapy had less inducible ventricular arrhythmia (odds ratio, 0.06 [0.03-0.11]; P < .01). This review highlights the rapid progress of AAV-mediated gene therapy for cardiac tachyarrhythmia. Although these investigations are currently in the early stages of clinical application, they present promising prospects for gene therapy. (PROSPERO registry: CRD42023479448).

A Simple Emergency Department-Based Score Predicts Complex Hospitalization in Patients with Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Thirty percent of inflammatory bowel disease (IBD) patients hospitalized with flare require salvage therapy or surgery. Additionally, 40% experience length of stay (LOS) > 7 days. No emergency department (ED)-based indices exist to predict these adverse outcomes at admission for IBD flare. We examined whether clinical, laboratory, and endoscopic markers at presentation predicted prolonged LOS, inpatient colectomy, or salvage therapy in IBD patients admitted with flare. METHODS: Patients with ulcerative colitis (UC) or colonic involvement of Crohn's disease (CD) hospitalized with flare and tested for Clostridioides difficile infection (CDI) between 2010 and 2020 at two urban academic centers were studied. The primary outcome was complex hospitalization, defined as: LOS > 7 days, inpatient colectomy, or inpatient infliximab or cyclosporine. A nested k-fold cross-validation identified predictive factors of complex hospitalization. RESULTS: Of 164 IBD admissions, 34% (56) were complex. Predictive factors included: tachycardia in ED triage (odds ratio [OR] 3.35; confidence interval [CI] 1.79-4.91), hypotension in ED triage (3.45; 1.79-5.11), hypoalbuminemia at presentation (2.54; 1.15-3.93), CDI (2.62; 1.02-4.22), and endoscopic colitis (4.75; 1.75-5.15). An ED presentation score utilizing tachycardia and hypoalbuminemia predicted complex hospitalization (area under curve 0.744; CI 0.671-0.816). Forty-four of 48 (91.7%) patients with a presentation score of 0 (heart rate < 99 and albumin ≥ 3.4 g/dL) had noncomplex hospitalization. CONCLUSIONS: Over 90% of IBD patients hospitalized with flare with an ED presentation score of 0 did not require salvage therapy, inpatient colectomy, or experience prolonged LOS. A simple ED-based score may provide prognosis at a juncture of uncertainty in patient care.

Macro-reentrant atrial tachycardia after tricuspid or mitral valve surgery: is there difference in electrophysiological characteristics and effectiveness of catheter ablation?

BACKGROUND: Macro-reentrant atrial tachycardias (MATs) are a common complication after cardiac valve surgery. The MAT types and the effectiveness of MAT ablation might differ after different valve surgery. Data comparing the electrophysiological characteristics and the ablation results of MAT post-tricuspid or mitral valve surgery are limited. METHODS: Forty-eight patients (29 males, age 56.1 ± 13.3 years) with MAT after valve surgery were assigned to tricuspid valve (TV) group (n = 18) and mitral valve (MV) group (n = 30). MATs were mapped and ablated guided by a three-dimensional navigation system. The one-year clinical effectiveness was compared in two groups. RESULTS: Nineteen MATs were documented in TV group, including 16 cavo-tricuspid isthmus (CTI)-dependent AFL and 3 other MATs at right atrial (RA) free wall, RA septum and left atrial (LA) roof. Thirty-nine MATs were identified in MV group, including15 CTI-dependent AFL, 8 RA free wall scar-related, 2 RA septum scar-related, 8 peri-mitral flutter, 3 LA roof-dependent, 2 LA anterior scar-related, and 1 right pulmonary vein-related MAT. Compared with TV group, MV group had significantly lower prevalence of CTI-dependent AFL (38.5% vs. 84.2%), higher prevalence of left atrial MAT (35.9 vs.5.3%) and higher proportion of patients with left atrial MAT (40 vs. 5.6%), P = 0.02, 0.01 and 0.01, respectively. The acute success rate of MAT ablation (100 vs. 93.3%) and the one-year freedom from atrial tachy-arrhythmias (72.2 vs. 76.5%) was comparable in TV and MV group. No predictor for recurrence was identified. CONCLUSION: Although the types of MATs differed significantly in patients with prior TV or MV surgery, the acute and mid-term effectiveness of MAT ablation was comparable in two groups. TRIAL REGISTRATION: This study was registered as a part of EARLY-MYO-AF clinical trial at the website ClinicalTrials. gov (NCT04512222).

Interatrial septal tachycardias following atrial fibrillation ablation or cardiac surgery: Electrophysiological features and ablation outcomes.

BACKGROUND: Interatrial septal tachycardias (IAS-ATs) following atrial fibrillation (AF) ablation or cardiac surgery are rare, and their management is challenging. OBJECTIVE: The purpose of this study was to investigate the electrophysiological features and outcomes associated with catheter ablation of IAS-AT. METHODS: We screened 338 patients undergoing catheter ablation of ATs following AF ablation or cardiac surgery. Diagnosis of IAS-AT was based on activation mapping and analysis of response to atrial overdrive pacing. RESULTS: Twenty-nine patients (9%) had IAS-AT (cycle length [CL] 311 ± 104 ms); 16 (55%) had prior AF ablation procedures (median 3; range 1-5), 3 (10%) had prior surgical maze, and 12 (41%) had prior cardiac surgery (including atrial septal defect surgical repair in 5 and left atrial myxoma resection in 1). IAS substrate abnormalities were documented in all patients. Activation mapping always demonstrated a diffuse early IAS breakout with centrifugal biatrial activation, and atrial overdrive pacing showed a good postpacing interval (equal or within 25 ms of the AT CL) only at 1 or 2 anatomically opposite IAS sites in all cases. Ablation was acutely successful in 27 patients (93%) (from only the right IAS in 2, only the left IAS in 9, both IAS sides with sequential ablation in 13, and both IAS sides with bipolar ablation in 3). After median follow-up of 15 (6-52) months, 17 patients (59%) remained free from recurrent arrhythmias. CONCLUSION: IAS-ATs are rare and typically occur in patients with evidence of IAS substrate abnormalities and prior cardiac surgery. Catheter ablation can be challenging and may require sequential unipolar ablation or bipolar ablation.

Discordant responses to his refractory premature ventricular beats (PVBs) during a regular narrow QRS tachycardia. What is the mechanism.

A 32-year-old lady was evaluated for recurrent episodes of palpitation. During one of the palpitation episodes a regular narrow QRS tachycardia was documented, and it got terminated with the administration of IV adenosine. The baseline 12 lead electrocardiogram (ECG) did not show any manifest preexcitation. There was no evidence of structural heart disease by echocardiogram. Patient underwent an electrophysiology (EP) study after informed consent. Quadripolar catheters were placed at the His region and right ventricular (RV) apex. A decapolar catheter was placed in the coronary sinus (CS) with CS 9, 10 dipoles at CS OS region and CS 1, 2 dipoles at CS distal region. A mapping & ablation catheter was positioned at right atrial (RA) appendage. Baseline atrial and ventricular pacing protocols could not be performed as both atrial and ventricular pacing were easily inducing a regular narrow QRS tachycardia. His refractory premature ventricular beats [PVBs] were delivered from RVRV apex and left ventricular [LV] free wall. Discordant responses were obtained. What is the mechanism?

Cigarette smoke exposure causes systemic and autonomic cardiocirculatory changes in rats depending on the daily exposure dose.

AIMS: To evaluate the systemic changes and autonomic cardiocirculatory control of awaken rats chronically exposed to the cigarette smoke (CS) of 1 or 2 cigarettes/day. MAIN METHODS: Rats were exposed to clean air (control) or cigarette smoke of 1 (CS1) or 2 (CS2) cigarettes/animal/day for 30 days. Then, arterial pressure (AP) and heart rate (HR) were recorded in conscious rats to assess spontaneous baroreflex sensitivity and HR and AP variabilities. Evoked baroreflex and cardiac autonomic tone were evaluated by vasoactive drugs and autonomic blockers, respectively. In another group, ventilatory and cardiovascular parameters were recorded under hypoxia and hypercapnia stimulus. At the end of protocols, heart, lung, kidneys and liver were collected for histological analysis. KEY FINDINGS: Rats exposed to CS showed morphological changes, being more evident in the CS2 group. Also, less weight gain and cardiac hypertrophy were prominent in CS2 rats. Basal AP and HR, spontaneous baroreflex sensitivity and cardiovascular variabilities were similar among groups. CS exposure progressively blunted the bradycardia response to phenylephrine (-2.2 ± 0.1 vs. -1.7 ± 0.2 vs. -1.5 ± 0.2) while the tachycardia response to sodium nitroprusside was slightly increased compared to control. Vagal tone was not affected by CS, but CS2 rats exhibited higher sympathetic tone (-25 ± 4 vs. -28 ± 4 vs. -56 ± 9) and lower intrinsic HR (411 ± 4 vs. 420 ± 8 vs. 390 ± 6). Exposure to CS of 2 cigarettes also exacerbated the reflex cardiovascular and ventilatory responses to hypoxia and hypercapnia. SIGNIFICANCE: CS exposure for 30 days promoted systemic changes and autonomic cardiocirculatory dysfunction in rats depending on the daily exposure dose.

Sympathetic hyperactivity, hypertension, and tachycardia induced by stimulation of the ponto-medullary junction in humans.

OBJECTIVE: The purpose of this study is to investigate changes in autonomic activities and systemic circulation generated by surgical manipulation or electrical stimulation to the human brain stem. METHODS: We constructed a system that simultaneously recorded microsurgical field videos and heart rate variability (HRV) that represent autonomic activities. In 20 brain stem surgeries recorded, HRV features and sites of surgical manipulation were analyzed in 19 hypertensive epochs, defined as the periods with transient increases in the blood pressure. We analyzed the period during electrical stimulation to the ponto-medullary junction, performed for the purpose of monitoring a cranial nerve function. RESULTS: In the hypertensive epoch, HRV analysis showed that sympathetic activity predominated over the parasympathetic activity. The hypertensive epoch was more associated with surgical manipulation of the area in the caudal pons or the rostral medulla oblongata compared to controls. During the period of electrical stimulation, there were significant increases in blood pressures and heart rates, accompanied by sympathetic overdrive. CONCLUSIONS: Our results provide physiological evidence that there is an important autonomic center located adjacent to the ponto-medullary junction. SIGNIFICANCE: A large study would reveal a candidate target of neuromodulation for disorders with autonomic imbalances such as drug-resistant hypertension.

Effect of variable annular reduction on functional tricuspid regurgitation and right ventricular dynamics in an ovine model of tachycardia-induced cardiomyopathy.

OBJECTIVE: To investigate the effect of variable tricuspid annular reduction (TAR) on functional tricuspid regurgitation (FTR) and right ventricular (RV) dynamics in ovine tachycardia-induced cardiomyopathy. METHODS: Nine adult sheep underwent implantation of a pacemaker with an epicardial lead and were paced at 200 to 240 bpm until the development of biventricular dysfunction and functional TR was noted. During reoperation on cardiopulmonary bypass, 6 sonomicrometry crystals were placed around the tricuspid annulus (TA) and 14 were placed on the RV epicardium. Annuloplasty suture was placed around the TA and externalized to an epicardial tourniquet. After weaning from cardiopulmonary bypass, echocardiographic, hemodynamic, and sonomicrometry data were acquired at baseline and during 5 progressive TARs achieved with suture cinching. TA area and RV free wall strains and function were calculated from crystal coordinates. RESULTS: After pacing, changes in left ventricular (LV) ejection fraction and RV fractional area decreased significantly. Mean TA diameter increased from 25.1 ± 2.9 mm to 31.5 ± 3.3 mm (P = .005), and median TR (range, 0-3+) increased from 0 (0) to 3 (2) (P = .004). Progressive suture cinching reduced the TA area by 18 ± 6%, 38 ± 11%, 56 ± 10%, 67 ± 9%, and 76 ± 8%. Only aggressive annular reductions (67% and 76%) decreased TR significantly, but these were associated with deterioration of RV function and strain. A moderate annular reduction of 56% led to a substantial reduction of TR with little deleterious effect on regional RV function. CONCLUSIONS: A moderate TAR of approximately 50% may be most advantageous for correction of functional TR and simultaneous maintenance of regional RV performance. Additional subvalvular interventions may be needed to achieve complete valvular competence.

Clinical sequelae of COVID-19 survivors in Wuhan, China: a single-centre longitudinal study.

OBJECTIVES: To describe the prevalence, nature and risk factors for the main clinical sequelae in coronavirus disease 2019 (COVID-19) survivors who have been discharged from the hospital for more than 3 months. METHODS: This longitudinal study was based on a telephone follow-up survey of COVID-19 patients hospitalized and discharged from Renmin Hospital of Wuhan University, Wuhan, China before 1 March 2020. Demographic and clinical characteristics and self-reported clinical sequelae of the survivors were described and analysed. A cohort of volunteers who were free of COVID-19 and lived in the urban area of Wuhan during the outbreak were also selected as the comparison group. RESULTS: Among 538 survivors (293, 54.5% female), the median (interquartile range) age was 52.0 (41.0-62.0) years, and the time from discharge from hospital to first follow-up was 97.0 (95.0-102.0) days. Clinical sequelae were common, including general symptoms (n = 267, 49.6%), respiratory symptoms (n = 210, 39%), cardiovascular-related symptoms (n = 70, 13%), psychosocial symptoms (n = 122, 22.7%) and alopecia (n = 154, 28.6%). We found that physical decline/fatigue (p < 0.01), postactivity polypnoea (p= 0.04) and alopecia (p < 0.01) were more common in female than in male subjects. Dyspnoea during hospitalization was associated with subsequent physical decline/fatigue, postactivity polypnoea and resting heart rate increases but not specifically with alopecia. A history of asthma during hospitalization was associated with subsequent postactivity polypnoea sequela. A history of pulse ≥90 bpm during hospitalization was associated with resting heart rate increase in convalescence. The duration of virus shedding after COVID-19 onset and hospital length of stay were longer in survivors with physical decline/fatigue or postactivity polypnoea than in those without. CONCLUSIONS: Clinical sequelae during early COVID-19 convalescence were common; some of these sequelae might be related to gender, age and clinical characteristics during hospitalization.

Pathophysiology and Acute Management of Tachyarrhythmias in Pheochromocytoma: JACC Review Topic of the Week.

Pheochromocytomas, arising from chromaffin cells, produce catecholamines, epinephrine and norepinephrine. The tumor biochemical phenotype is defined by which of these exerts the greatest influence on the cardiovascular system when released into circulation in high amounts. Action on the heart and vasculature can cause potentially lethal arrhythmias, often in the setting of comorbid blood pressure derangements. In a review of electrocardiograms obtained on pheochromocytoma patients (n = 650) treated at our institution over the last decade, severe and refractory sinus tachycardia, atrial fibrillation, and ventricular tachycardia were found to be the most common or life-threatening catecholamine-induced tachyarrhythmias. These arrhythmias, arising from catecholamine excess rather than from a primary electrophysiologic substrate, require special considerations for treatment and complication avoidance. Understanding the synthesis and release of catecholamines, the adrenoceptors catecholamines bind to, and the cardiac and vascular response to epinephrine and norepinephrine underlies optimal management in catecholamine-induced tachyarrhythmias.

Dexmedetomidine aggravates hypotension following mesenteric traction during total gastrectomy: a randomized controlled trial.

BACKGROUND: Mesenteric traction syndrome (MTS), which is characterized by arterial hypotension and tachycardia following mesenteric traction (MT), frequently occurs during abdominal surgery. Dexmedetomidine, commonly used in general anesthesia during major surgery, has a sympatholytic effect and attenuates the compensatory response to hypotension. OBJECTIVE: Assess the effect of dexmedetomidine on hypotension following mesenteric traction. DESIGN: Prospective, randomized, controlled clinical trial. SETTING: Department of Anesthesiology, Zhenjiang First People's Hospital in China. PATIENTS AND METHODS: Patients were randomly divided into three groups. Dexmedetomidine, 0.5 or 1.0 µg/kg, was intravenously administered over 15 minutes before skin incision followed by a maintenance rate of 0.5 µg/kg/h in groups D1 and D2, respectively; saline was administered in group C. MAIN OUTCOME MEASURE(S): The duration of hypotension, heart rate and plasma norepinephrine level in patients with MTS were recorded within 60 minutes following MT. SAMPLE SIZE: 75 patients. RESULTS: The duration of hypotension in the MTS patients in group D1 and D2 was significantly longer than that in groups C (D1 vs. C, P<.05; D2 vs. C, P<.01). Significantly more phenylephrine was required to treat hypotension in group D1 and D2 than was required for patients in group C (P<.05). The increase in heart rate during the first 15 minutes of MT in group D2 was significantly attenuated compared to that in group C (P<.0083). The increases in norepinephrine levels during the first 15 minutes of MT in group C were significantly higher than those in groups D1 and D2 (P<.0167). CONCLUSION: Adjunctive dexmedetomidine in general anesthesia aggravates hypotension during MTS in open total gastrectomy. LIMITATIONS: Postoperative complications were not evaluated. CONFLICT OF INTEREST: None.

The Haemodynamic Response to Endotracheal Intubation at Different Time of Fentanyl Given During Induction: A Randomised Controlled Trial.

Endotracheal intubation elicits huge spectrum of stress responses which are hazardous in high-risk patients. Numerous drugs and techniques have been applied to attenuate the stress responses. In this double-blind study, one hundred and forty-five patients over 20 years old, ASA physical status I and II, undergoing elective surgeries requiring general anaesthesia with endotracheal intubation were included. Patients were randomly divided into three groups which fentanyl 2 mcg/kg was given at either 1, 2, 3 minutes before intubation. All groups received midazolam 0.05 mg/kg, lidocaine 0.5 mg/kg, propofol 2 mg/kg and rocuronium 1 mg/kg before intubation. Haemodynamic parameters were recorded for 10 minutes after induction. Two-level longitudinal hierarchical linear models were used for data interpretation and P < 0.05 was considered statistically significant. The study demonstrated significantly lower haemodynamic responses in the group who received fentanyl 2 minutes before intubation (P < 0.05). Confounding factors such as smoking, hypertension, diabetes mellitus and preoperative intravenous fluid supplement were analysed. In conclusion, fentanyl injection 2 minutes before intubation is recommended in order to obtain the most stable haemodynamic status.

Diagnóstico diferencial de las taquicardias de complejo ancho: un desafío permanente / Wide QRS tachycardia: a diagnostic challenge

El diagnóstico electrocardiográfico correcto de la causa de una taquicardia de complejo QRS ancho (TCA) es fundamental, ya que tanto el manejo, como el pronóstico del paciente, es diferente según su etiología, y define el estudio que debemos realizar. Numerosos criterios y algoritmos han sido descritos para diferenciar el origen de estas taquicardias. Sin embargo, muchos de estos son complejos y difíciles de aplicar para el médico menos experimentado. Esto es particularmente importante en los servicios de emergencia, donde se necesita una definición rápida que permita un manejo agudo apropiado. En la presente revisión analizamos los diferentes mecanismos de las TCA y los principales criterios diagnósticos en el ECG, reforzando, especialmente, aquellos de aplicación rápida y de alto rendimiento diagnóstico.

The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis of the patient. The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis is different according to its etiology and defines the study that we should perform. Numerous criteria and algorithms have been described to differentiate the origin of these tachycardias. However, many of these are complex and difficult to apply to the less experienced doctor. This is particularly important in emergency rooms, where a rapid definition is needed to allow proper therapy. In this review we analyze the different mechanisms of WCT and the main EKG diagnostic criteria, emphasizing those which can be applied rapidly and have high diagnostic value.

Pediatric Bupropion Ingestions in Adolescents vs. Younger Children-a Tale of Two Populations.

BACKGROUND: Bupropion is a unique class of antidepressant. In overdose, it is associated with tachycardia, altered mental status, and a dose-dependent risk of seizures, which can be delayed. Despite being a common medication, there is a paucity of data comparing toxicity in younger versus older children with bupropion exposures. The primary purpose of this study is to examine bupropion toxicity in pediatric patients and assess for toxicity differences between younger and older (teenaged) groups. METHODS: This single-center, observational cohort study reviewed pediatric patients presenting to a toxicology service between 2011 and 2018. The primary outcome measures evaluated were the presence of any seizure, delayed seizure (defined as occurring at least 6 hours after hospital arrival), and a composite endpoint of seizure, hypotension, or need for endotracheal intubation. Patients were subdivided into two groups-those 12 years and under, compared with those 13-17 years. RESULTS: A total of 80 unique pediatric cases were identified. Overall, the median (IQR) age was 14 (2.4-16) years. Patients under 13 years accounted for 31 (39%) of cases, whereas the remaining 49 cases were adolescents. Compared with the adolescents, the younger patients were less likely to be female (41.9% vs. 71.4%; p = 0.009) and more likely to have an unintentional ingestion (100% vs. 10.2%; p < 0.001). The younger group was more likely to present to health care earlier after the ingestion (median 61 (IQR 39-103) min vs. 139 (67-399) min; p = 0.002). The older group was more likely to be tachycardic (73.5% vs. 19.4%; p < 0.001), have sustained tachycardia (71.4% vs. 29% p < 0.001), and more likely to have altered mental status on arrival (38.8% vs. 6.5%; p < 0.001). Seizures were also much more likely in the older group (40.8% vs. 3.2%; p < 0.001). Adolescents were much more likely than younger children to reach the pre-defined composite endpoint (42.9% vs. 6.5%; p < 0.001), but this was largely driven by the seizures. CONCLUSION: Bupropion ingestions are relatively common among pediatric patients. However, adolescents are much more likely to present with more severe toxicity. Seizures are uncommon among younger children with exploratory ingestions.

Spinal cord injury alters purinergic neurotransmission to mesenteric arteries in rats.

Complications associated with spinal cord injury (SCI) result from unregulated reflexes below the lesion level. Understanding neurotransmission distal to the SCI could improve quality of life by mitigating complications. The long-term impact of SCI on neurovascular transmission is poorly understood, but reduced sympathetic activity below the site of SCI enhances arterial neurotransmission (1). We studied sympathetic neurovascular transmission using a rat model of long-term paraplegia (T2-3) and tetraplegia (C6-7). Sixteen weeks after SCI, T2-3 and C6-7 rats had lower blood pressure (BP) than sham rats (103 ± 2 and 97 ± 4 vs. 117 ± 6 mmHg, P < 0.05). T2-3 rats had tachycardia (410 ± 6 beats/min), and C6-7 rats had bradycardia (299 ± 10 beats/min) compared with intact rats (321 ± 4 beats/min, P < 0.05). Purinergic excitatory junction potentials (EJPs) were measured in mesenteric arteries (MA) using microlectrodes, and norepinephrine (NE) release was measured using amperometry. NE release was similar in all groups, while EJP frequency-response curves from T2-3 and C6-7 rats were left-shifted vs. sham rats. EJPs in T2-3 and C6-7 rats showed facilitation followed by run-down during stimulation trains (10 Hz, 50 stimuli). MA reactivity to exogenous NE and ATP was similar in all rats. In T2-3 and C6-7 rats, NE content was increased in left cardiac ventricles compared with intact rats, but was not changed in MA, kidney, or spleen. Our data indicate that peripheral purinergic, but not adrenergic, neurotransmission increases following SCI via enhanced ATP release from periarterial nerves. Sympathetic BP support is reduced after SCI, but improving neurotransmitter release might maintain cardiovascular stability in individuals living with SCI.NEW & NOTEWORTHY This study revealed increased purinergic, but not noradrenergic, neurotransmission to mesenteric arteries in rats with spinal cord injury (SCI). An increased releasable pool of ATP in periarterial sympathetic nerves may contribute to autonomic dysreflexia following SCI, suggesting that purinergic neurotransmission may be a therapeutic target for maintaining stable blood pressure in individuals living with SCI. The selective increase in ATP release suggests that ATP and norepinephrine may be stored in separate synaptic vesicles in periarterial sympathetic varicosities.

Effects of Anticholinesterase Reversal Under General Anesthesia on Postoperative Cardiovascular Complications: A Retrospective Cohort Study.

BACKGROUND: The anticholinesterase neostigmine and the muscarinic inhibitor glycopyrrolate are frequently coadministered for the reversal of neuromuscular blockade. This practice can precipitate severe bradycardia or tachycardia, but whether it affects the incidence of cardiovascular complications remains unclear. We hypothesized that anticholinesterase reversal with neostigmine and glycopyrrolate versus no anticholinesterase reversal increases the risk of postoperative cardiovascular complications among adult patients undergoing noncardiac surgery with general anesthesia. METHODS: We conducted a prespecified retrospective analysis of hospital registry data from a major health care network for patients undergoing surgery with general anesthesia from January 2007 to December 2015. The primary outcome was a composite of cardiac dysrhythmia, acute heart failure, transient ischemic attack, ischemic stroke, and acute myocardial infarction within 30 days after surgery. We performed sensitivity analyses in subgroups and propensity score adjustment and explored the association between exposure and outcome in subgroups of patients with high risk of cardiovascular complications. RESULTS: Of the 98,147 cases receiving neuromuscular blockade, 73,181 (74.6%) received neostigmine and glycopyrrolate, while 24,966 (25.4%) did not. A total of 5612 patients (7.7%) in the anticholinesterase reversal group and 1651 (6.6%) in the control group (P < .001) experienced the primary outcome. After adjustment for clinical covariates, neostigmine and glycopyrrolate exposure was significantly associated in a dose-dependent fashion (P for trend <.001, respectively) with tachycardia (adjusted odds ratio = 2.1 [95% CI, 1.97-2.23]; P < .001) and bradycardia (adjusted odds ratio = 2.84 [95% CI, 2.49-3.24]; P < .001) but not with postoperative cardiovascular complications (adjusted odds ratio = 1.03 [95% CI, 0.97-1.1]; P = .33). We identified a significant effect modification of anticholinesterase reversal by high age, high-risk surgery, and history of atrial fibrillation (P for interaction = .002, .001, and .02, respectively). By using linear combinations of main effect and exposure-risk interaction terms, we detected significant associations between anticholinesterase reversal and cardiovascular complications toward a higher vulnerability in these patient subgroups. CONCLUSIONS: Neuromuscular blockade reversal with neostigmine and glycopyrrolate was associated with an increased incidence of intraoperative tachycardia and bradycardia but not with 30-day postoperative cardiovascular complications. Exploratory analyses suggest that a high postoperative cardiovascular complication risk profile may modify the effects of anticholinesterase reversal toward clinical relevance.