Triglicerydes/high-density lipoprotein ratio as a risk factor of post-Covid-19 sinus tachycardia: A retrospective study.

Inappropriate sinus tachycardia (IST) is one of the manifestations of the post-COVID-19 syndrome (PCS), which pathogenesis remains largely unknown. This study aimed to identify potential risk factors for IST in individuals with PCS. The 1349 patients with PCS were included into the study. Clinical examination, 24H Holter ECG, 24H ambulatory blood pressure monitoring and biochemical tests were performed 12-16 weeks after the COVID-19 in all participants. IST was found in 69 (3.5%) individuals. In the clinical assessment IST patients were characterized by a higher age (p < 0.001) and lower prevalence of the diagnosed hypertension (p = 0.012), compared to remaining patients. Biochemical testing showed higher serum triglycerides (1.66 vs. 1.31 pmol/L, p = 0.007) and higher prevalence of a low high-density lipoprotein (HDL) cholesterol (24.6% vs. 15.2%, p = 0.035) in the IST group. Subsequently, the triglicerydes (TG)/HDL ratio, an indicator of insulin resistance, was significantly higher in the IST individuals (3.2 vs. 2.4, p = 0.005). 24H monitoring revealed a significantly higher minimum diastolic, maximum systolic and mean arterial blood pressure values in the IST group (p < 0.001 for all), suggesting a high prevalence of undiagnosed hypertension. A multivariate analysis confirmed the predictive value TG/HDL ratio >3 (OR 2.67, p < 0.001) as predictors of IST development. A receiver operating characteristic curve analysis of the relationship between the TG/HDL ratio and the IST risk showed that the predictive cut-off point for this parameter was 2.46 (area under the ROC curve = 0.600, p = 0.004). Based on these findings, one can conclude that insulin resistance seems to be a risk factor of IST, a common component of PCS.

Redo procedures after sinus node sparing hybrid ablation for inappropriate sinus tachycardia/postural orthostatic sinus tachycardia.

AIMS: A novel sinus node (SN) sparing hybrid ablation for inappropriate sinus node tachycardia (IST)/postural orthostatic tachycardia syndrome (POTS) has been demonstrated to be an effective and safe therapeutic option in patients with symptomatic drug-resistant IST/POTS. The aim of this study was to evaluate the long-term rate of redo procedures after hybrid IST ablation and procedural strategy, outcomes and safety of redo procedures. METHODS AND RESULTS: All consecutive patients from 2015 to 2023 were prospectively enrolled in the UZ Brussel monocentric IST/POTS registry. They were analysed if the following inclusion criteria were fulfilled: 1) diagnosis of IST or POTS, 2) symptomatic IST/POTS refractory or intolerant to drugs, and 3) hybrid SN sparing ablation performed. The primary endpoint was redo procedure. The primary safety endpoint was pacemaker (PM) implantation. A total of 220 patients undergone to hybrid IST ablation were included, 185 patients (84.1%) were treated for IST and 61 patients (27.7%) for POTS.After a follow-up of 73.3 ± 16.2 months, 34 patients (15.4%) underwent a redo. A total of 23 patients (67.6%) had a redo for IST recurrence and 11 patients (32.4%) for other arrhythmias. Pacemaker implantation was performed in 21 patients (9.5%). Nine patients (4.1%) had no redo procedure and experienced sick sinus syndrome requiring a PM. Twelve patients (5.4%) received a PM as a shared therapeutic choice combined with SN ablation procedure. CONCLUSION: In a large cohort of patients the long-term free survival from redo procedure after hybrid IST ablation was 84.6% with a low PM implantation rate.

Inappropriate sinus tachycardia: an examination of existing definitions.

AIMS: Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological causes. Despite published consensus documents, IST definitions appear to vary in the literature. In this study, we reviewed IST publications to evaluate IST definition variability and ascertain the degree to which consensus definitions are being adopted. METHODS AND RESULTS: English-language articles in PubMed, Ovid MEDLINE, Ovid Embase, and Google Scholar published from 1 January 1970 to 1 June 2021 with the title terms 'inappropriate sinus tachycardia,' 'non-paroxysmal sinus tachycardia,' or 'permanent sinus tachycardia' were searched. In each, the IST definition used, qualifying characteristics, and publications cited to support each definition were recorded. We identified 138 publications meeting the search criteria. Inappropriate sinus tachycardia definitions were provided in 114 of 138 articles (83%). A majority of definitions (92/114, 81%) used distinct heart rate (HR) thresholds. Among these, the most common threshold was ≥100 beats per minute (BPM) (75/92, 82%), mainly measured at rest (54/92, 59%). Most definitions (47/92, 51%) included a second criterion to qualify for IST; these were most often an HR threshold of 90 BPM measured over 24 h by ambulatory electrocardiogram (37/47, 79%). Diagnosis of exclusion was a common criterion (75/92, 82%) but symptom status was not (41/92, 45%). The 2015 Heart Rhythm Society IST consensus was commonly cited but adopted in only 37% of definitions published after 2015. CONCLUSIONS: Inappropriate sinus tachycardia definitions in current literature are inconsistent, and professional society consensus IST definitions have, to date, had limited impact.

Efficacy of medical and ablation therapy for inappropriate sinus tachycardia: A single-center experience.

BACKGROUND: Effective therapy for inappropriate sinus tachycardia (IST) remains challenging with high rates of treatment failure and symptom recurrence. It is uncertain how effective pharmacotherapy and procedural therapy are long-term, with poor response to medical therapy in general. METHODS: We retrospectively reviewed all patients with the diagnosis of IST at a tertiary academic medical center from 1998 to 2018. We extracted data related to prescribing patterns and symptom response to medical therapy and sinus node modification (SNM), assessing efficacy and periprocedural complication rates. RESULTS: A total of 305 patients with a formal diagnosis of IST were identified, with 259 (84.9%) receiving at least one prescription medication related to the condition. Beta-blockers were the most commonly used medication (n = 245), with a majority of patients reporting no change or worsening of symptoms, and poor response was seen to other medication classes. Improvement was seen significantly more often with ivabradine than beta blockers, though the sample size was limited (p = .003). Fifty-five patients (18.0% of all IST patients), mean age 32.0 ± 9.1 years, underwent a SNM procedure, with an average of 1.8 ± 0.9 procedures per patient. Acute symptomatic improvement (<6 months) was seen in 58.2% of patients. Long-term complete resolution of symptoms was seen in 5.5% of patients, modest improvement in 29.1%, and no long-term benefit was seen in 65.5% of patients. CONCLUSIONS: Among all medical therapies, there were high rates of treatment failure or symptom worsening in over three-quarters of patients in our study. Ivabradine was most beneficial, though the sample size was small. While most patients receiving SNM ablation for IST perceive an acute symptomatic improvement, almost two-thirds of patients have no long-term improvement, and resolution of symptoms is quite rare. AV node ablation with pacemaker implantation following lack of response to SNM offered increased success, though the sample size was limited.

Inappropriate sinus tachycardia: a review.

Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing symptoms resulting from the persistent tachycardia. IST is prevalent in 1% of the middle-aged population, mostly females. Rarely can elderly patients also present with IST. Possible mechanisms of IST include intrinsic sinus node abnormality, beta-adrenergic receptor stimulating autoantibody, beta-adrenergic receptor supersensitivity, muscarinic receptor autoantibody, or hyposensitivity, impaired baroreflex control, depressed efferent parasympathetic/vagal function, nociceptive stimulation, central autonomic overactivity, aberrant neurohumoral modulation, etc. Symptoms associated with IST are palpitations, chest pain, fatigue, shortness of breath, presyncope, and syncope. Despite these distressing symptoms, IST has not been associated with tachycardia-associated cardiomyopathy or increased major cardiovascular events. Various treatment options for patients with IST are ivabradine, beta-adrenergic blockers, calcium channel blockers, psychiatric evaluation, and exercise training. Although, endocardial radiofrequency ablation targeting the sinus node has been used as a treatment modality for otherwise treatment-refractory IST, the results have been dismal. The other modalities used for refractory IST treatment are endocardial modification of the sinus node using radiofrequency energy, combined endo and epicardial ablation of the sinus node, thoracoscopic epicardial ablation of the sinus node, sinus node sparing thoracoscopic and endocardial hybrid ablation. The goal of this review is to provide the readership with the pathophysiological basis of IST and its management options.

Prognosis and role of clinical and imaging features in patients with malignant pericardial effusion: a single-center study in China.

BACKGROUND: The diagnosis of malignant pericardial effusion (MPE) is often associated with a poor prognosis, but due to the complexity and unspecific nature of MPE patients' clinical manifestations, imaging often performs an essential role in diagnosis and prognosis. METHODS: Patients diagnosed with MPE between 2013 and 2018 at one tumor hospital were included and followed up. The data covered the basic clinical features, imaging findings, treatments and prognosis of patients with MPE, and the factors that may have affected the prognosis were explored. RESULTS: A total of 216 patients with MPE were included with the median age of 60 years. The most common primary cancer type was lung cancer (73.6%), the most common symptom was dyspnea (62.9%) and the most common abnormal electrocardiogram finding was sinus tachycardia (42.1%). The median survival time of the 216 patients with MPE was 13.7 months. The factors affecting prognosis were echocardiographic fluid signs (HR = 2.37, P = 0.010), electrocardiographic evidence of sinus tachycardia (HR = 1.76, P = 0.006) and echocardiographic evidence of cardiac tamponade (HR = 3.33, P < 0.001). CONCLUSIONS: MPE has complex clinical manifestations and an unsatisfactory prognosis. Echocardiographic fluid signs, electrocardiographic evidence of sinus tachycardia, and echocardiographic evidence of cardiac tamponade are independent risk factors affecting prognosis.

Natural history and clinical outcomes of inappropriate sinus tachycardia.

BACKGROUND: Limited data are available regarding the demographics, disease associations, and long-term prognosis of patients with inappropriate sinus tachycardia (IST). OBJECTIVE: To establish epidemiologic data for patients with IST, including symptom onset, comorbid disease, and long-term outcomes. METHODS: We retrospectively reviewed all patients with an IST diagnosis at the Mayo Clinic (Rochester, MN) during a 20-year period (1998-2018). We extracted demographic data and clinical outcomes compared to an age and gender-matched control group with atrioventricular nodal reentry tachycardia (AVNRT). RESULTS: Within the study period, a total of 305 patients with IST were identified (mean follow-up 3.5 years) with 92.1% female and mean age 33.2 ± 11.2 years. The most frequently identified circumstances triggering the condition included pregnancy (7.9%) and infectious illness (5.9%) while the most common comorbid conditions were depression (25.6%) and anxiety (24.6%). At diagnosis, the mean left ventricular ejection fraction (LVEF) was 62.3 ± 6.2%, with 77 patients having follow-up echocardiographic data. No significant difference in LVEF was seen after a mean 4.9 ± 4.3-year follow-up (baseline LVEF 59.8 ± 10.7% vs subsequent 61.4 ± 8.1%; P = .2971). Two deaths occurred within the study period, with one related to myocardial infarction and the other noncardiac; compared to an age and gender-matched AVNRT control group there was no excess mortality during the follow-up period. CONCLUSIONS: In our study cohort, IST predominately affects young females with structurally normal hearts and modest coexistent psychiatric disease. In most cases of IST, a major event occurring just before or at the time of diagnosis could not be identified, although nearly 8% of patients first noted symptoms during or shortly after pregnancy. In our cohort, there was no evidence of cardiomyopathy or mortality related to IST.

Baseline intrinsic heart rate and response to ivabradine treatment in patients with inappropriate sinus tachycardia.

BACKGROUND: Treatment with ivabradine became a new therapeutic alternative for patients with inappropriate sinus tachycardia (IST). The aim was to determine a relation between intrinsic heart rate (IHR) and response to ivabradine treatment. METHODS: Twenty-seven patients (mean age 37 ± 11; 23 women) with symptomatic IST despite medical treatment were recruited into the study. Resting ECG, 24-hr ECG monitoring (24hECG), exercise treadmill test, and symptoms evaluation were performed initially and after 60 days on ivabradine. IHR was acquired at baseline after pharmacological autonomic blockade. RESULTS: Nineteen patients (70%) were classified as abnormal IHR group (AIHR) while eight showed normal IHR (NIHR). No significant differences in ECG parameters were found between NIHR and AIHR subgroups, while baseline exercise capacity was higher in AIHR patients (10.9 vs. 9.5 METs, p < .05). Ivabradine treatment resulted in significant reduction in resting heart rate, average 24hECG heart rate, improvement in exercise capacity and reduction of symptoms in both subgroups. Nevertheless, favorable influence of ivabradine was significantly more exaggerated in AIHR subgroup (HR 116 vs. 90 bpm, av. HR 98 vs. 79 bpm, 10.9 vs. 13.6 METS, EHRA score 3.1 vs. 1.1, p < .001 for all) than in NIHR patients (HR 112 vs. 98 bpm, av. HR 97 vs. 88 bpm, 9.5 vs. 11.1 METs, EHRA score 3.1 vs. 1.9; p < .05 for all). CONCLUSIONS: Intrinsic heart rate may be useful in predicting response to ivabradine in patients with IST. More intense response to ivabradine in patients with AIHR may be attributed to different pathophysiological mechanisms underlying IST in AIHR and NIHR groups.

Minimally invasive thoracoscopic surgery is an effective approach for treating inappropriate sinus tachycardia.

INTRODUCTION: Inappropriate sinus tachycardia (IST) is characterized by increased heart rate out of proportion to normal physiologic demand. IST ablation is challenging for the electrophysiology community due to the epicardial location of the sinus node and the risk of phrenic nerve (PN) injury during catheter ablation. In this study, we investigated the safety and efficacy of a minimally invasive thoracoscopic surgery for elimination of IST. METHODS: Patients with IST who failed medical therapy or endocardial ablation underwent minimally invasive thoracoscopic epicardial ablation. Epicardial activation mapping was performed to identify the earliest activation site and any possible migration of earliest activation along the lateral right atrium. The PN in each patient was protected by a pericardial retraction suture. RESULTS: From 1 January 2000 to 15 June 2018, 10 patients (eight females and two males) underwent minimally invasive thoracoscopic IST ablation. Mean age of the patients was 36.7 ± 12.5 years. Mean baseline sinus rate was 113.8 ± 21.8 beats per minute. After surgery, the mean heart rate significantly decreased to 79.8 ± 8.2 at postoperative day 1 and to 75.8 ± 8.1 at day 30 (both P < .001). No in-hospital death, stroke, or PN injury occurred. One patient required reintubation, one patient developed postoperative pericarditis, and another patient had a pulmonary embolus. Median follow-up was 6 months (range, 1-50). Freedom from reintervention was 88% at 6 months. CONCLUSION: Minimally invasive thoracoscopic ablation for IST is a safe and effective approach that preserves the phrenic nerve. Due to the possibility of IST activation site migration, continued follow-up after surgery is required.

Stellate ganglion block and cardiac sympathetic denervation in patients with inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy. OBJECTIVE: To study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST. METHODS: Twelve consecutive patients who had drug-refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD. RESULTS: The mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement. CONCLUSION: SG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.

Inappropriate sinus tachycardia.

Inappropriate sinus tachycardia (IST) is a clinical syndrome, oftentimes debilitating, defined by fast sinus rates (>100 b.p.m. at rest or >90 b.p.m. on average over 24 h and not due to underlying causes) associated with symptoms that may include palpitations, as described in some guidelines and consensus documents. While heart rates may vary by patient, especially based upon gender and age, some individuals experience sinus tachycardia or persistent fast sinus rates with no symptoms; these individuals would not necessarily be considered to have the syndrome of IST. Various explanations for IST have been considered but a definitive common mechanism is not yet known; the true aetiology may be multifactorial. A thorough evaluation of secondary causes of tachycardia is required in the work-up of all cases and if found, must be treated before a diagnosis of IST can be made. Finally, effective treatments vary but can include ivabradine, beta-blockers, or calcium channel antagonists; ablation is seldom advised.

Sinus tachycardia presenting as a wide and narrow complex tachyarrhythmia: What is the 'link'?

We describe a neonate that developed alternating wide and narrow complex tachycardias following heart surgery for congenital heart defect. Although the etiology was sinus tachycardia, a premature atrial complex initiated aberrancy due to phase 3 block that was perpetuated due to 'linking' at similar or even slower heart rates. Similarly, there was abrupt transition from wide to narrow complex tachycardia following a premature ventricular complex without a change in subsequent heart rate. This was explained by interruption of linking phenomenon by premature ventricular activation. While the above mechanisms are described in the setting of a supraventricular tachyarrhythmia, this has not been reported during sinus tachycardia.

Predictors of left ventricular systolic function recovery in the setting of sinus tachycardia in patients with cancer.

OBJECTIVES: To identify unique echocardiographic features that could be used to reliably predict LVEF recovery upon resolution of sinus tachycardia in patients with cancer. BACKGROUND: Sinus tachycardia may be a manifestation of underlying cardiomyopathy or can lead to a reversible form of dilated cardiomyopathy known as tachycardia-mediated cardiomyopathy. While distinguishing the two can be challenging, predicting recovery regardless of cause can be of significant clinical importance in the cancer population. METHODS: Results of echocardiograms performed were collected. Patients with a repeat echocardiogram within 6 months of the initial echocardiogram were included. Patients with structural heart disease, acute coronary syndrome, sepsis, and pericardial disease were excluded. A comparison between baseline echocardiogram and subsequent echocardiogram was made to determine whether specific echocardiographic parameters predicted LVEF recovery. Two groups of patients were defined at the outset of the study. The recovered group was comprised of patients with reduced LVEF in the setting of sinus tachycardia and normal LVEF with resolution of tachycardia to normal sinus rhythm (NSR). The unrecovered group was comprised of subjects with low LVEF in the setting of both sinus tachycardia and NSR. RESULTS: A total of 40 patients were included in the study. LVEF in the recovered group (n=18) was 42.8% with sinus tachycardia and increased to 58.3% with NSR. Average LVEF in the unrecovered group (n=22) was 35.1% with tachycardia and improved to 38.5% with NSR. Medial TDI (E') was significantly greater in the recovered group with both tachycardia (7.95 cm/s versus 4.56 cm/s, P<.001) and NSR (8.11 cm/s versus 5.13 cm/s, P<.001). Similarly, lateral TDI (E') was significantly greater in the recovered group than in the unrecovered group during tachycardia (8.97 cm/s versus 5.13 cm/s, P<.001) and NSR (9.05 cm/s versus 5.13 cm/s, P<.001). Multivariable logistic regression analysis showed that medial TDI >6.5 cm/s (OR=30.9, P=.001) and lateral TDI >7.8 cm/s (OR=52.5, P=.002) are positively associated with the probability of LVEF recovery. CONCLUSIONS: In conclusion, TDI (medial E'>6.5 cm/s; lateral E'>7.8 cm/s) appears to predict LVEF recovery in patients with sinus tachycardia upon resolution of the tachycardia in patients with cancer.

The utility of Valsalva maneuver in the diagnoses of orthostatic disorders.

The objective of this study was to assess hemodynamic responses and baroreflex sensitivity (BRS) indexes during Valsalva maneuver (VM) and head-up tilt (HUT) testing in orthostatic intolerance (OI). Patients with neurogenic orthostatic hypotension (NOH, n = 26), postural tachycardia syndrome (n = 26) and symptomatic OI (n = 14) were compared with healthy population (control, n = 107) and inappropriate sinus tachycardia (n = 7). Hemodynamic assessment included patterning and quantification with vagal and adrenergic BRS (BRSa/BRSa1). In NOH, cardiovagal systolic blood pressure (SBP) decrements in VM and HUT were correlated (r = 0.660, P < 0.001); a "V" pattern of VM indicated α-BRSa failure. Yet BRSa1 did not reveal changes vs. control (P > 0.05) or was not applicable in 60% of NOH. In symptomatic OI, compared with control, cardiovagal SBP decrements were larger (P < 0.05); higher BRSa1 contradicted higher adrenergic index (Composite Autonomic Severity Score). Overshoot in phase IV dipped below baseline or dropped ≥ 10 mmHg over 8 s in postural tachycardia syndrome ("N" pattern), but by 3 s in inappropriate sinus tachycardia ("M" pattern). Visualization of distinct VM patterns allows primary evaluation of autonomic dysfunction and differentiation of the various forms of OI. BRSa1 evaluation is compromised by pathological SBP patterns. VM patterning is a valuable nonpostural supplement to HUT capable of detecting and differentiating OI.