Prevalence and predictors of acquired long QT syndrome in the ER department

Introduction

Long QT syndrome (LQTS) is a rare heterogeneous syndrome that may be congenital or acquired, the latter being more common. Its real-world prevalence remains to be determined. We aimed to determine the prevalence of this syndrome in patients admitted to the emergency room (ER) and characterize the subset of patients with severely prolonged QT.

Methods

A retrospective analysis of ECG of all consecutively admitted patients in the ER of a tertiary hospital between the 28th of January and the 17th of March 2020 was made. All patients with Bazzett corrected QT interval greater than 470ms in men and 480ms in women were included. Repeated ECGs or with bad electrocardiographic quality, congenital LQTS, atrial fibrillation and pacemaker rhythm were excluded. Clinical data with a special focus on QT prolonging drugs and clinical factors were recorded. Statistical comparison was made between the groups with and without QT interval greater than 500ms.

Results

A total of 6280 ECGs of 5056 patients were analysed. After evaluation, 390 ECGs from 387 different patients were considered. Prevalence of LQTS at admission was 7.95%. Patients were more commonly men (53.1%) with an average age of 73.6±14.7 years old and mean QTc interval of 502.14±32.2ms. Only 20% of the patients were symptomatic, with the most common form of presentation being syncope (50%). No ventricular arrhythmias were recorded.

Regarding patients with a QT interval greater than 500ms, these were more frequently female (59.9% vs 37.2%, p<0.001), were more frequently on QT prolonging drugs (77.8% vs 67.3%; p=0.002). Presence of clinical risk factors was not a risk factor per se (p=0.811) but a greater number of risk factors was linked to more severely prolonged QT (p=0.040). The main contributing factor was intake of antibiotics (odds ratio (OR) 3.497; CI 95% 1.074–11.321; p=0.038) followed by female gender (OR 2.518; CI 95% 1.668–3.800; p<0.001) and use of antipsychotics (OR 1.960; CI 95% 1.159–3.316; p=0.012).

Conclusions

Acquired LQTS is particularly prevalent in the ER setting. The complex interaction of clinical factors and drug iatrogenesis and the unpredictability of its manifestations render its management and recognition difficult but essential. Female patients on antibiotics and antipsychotics are at particularly high risk. Efforts must be made in order to avoid, detect and treat acquired LQTS as early as possible.

Funding Acknowledgement

Type of funding sources: None.

Impact of obstructive sleep apnoea on long-term atrial fibrillation-free survival after catheter ablation

Introduction

Early rhythm-control therapy of atrial fibrillation (AF) (including catheter ablation) has been established as significantly lowering risk of adverse cardiovascular outcomes and improving overall survival and quality of life. Obstructive sleep apnoea (OSA) is a common but often overlooked comorbidity in patients with AF that may lead to difficulties in maintaining sinus rhythm. Data on the impacts of its treatment on recurrence remain conflicting.

Objective

To determine the prevalence of OSA in a population of AF patients submitted to catheter ablation and its impact on recurrence after a successful procedure.

Methods

Retrospective study of patients with AF consecutively submitted to catheter ablation in a tertiary centre between January 2017 and December 2020. The main outcome was AF recurrence after ablation. Sociodemographic variables and clinical data were retrieved for each patient, including type of AF, comorbidities, screening and diagnosis of OSA, treatment of OSA prior to ablation, time from ablation to recurrence of AF, method of ablation (radiofrequency or cryo). Statistical comparison between patients with and without OSA was made, including survival curves and Cox regression to determine time to recurrence and adjust for confounding variables.

Results

A total of 189 patients were included with a mean age of 63.49±11.09 years. Mean follow-up time after ablation was 2.76±1.56 years. Patients who recurred after ablation had undergone more electrical cardioversions prior to the procedure (1.640±1.583 vs 0.800±0.966, p 0.002), had more persistent AF (p 0.036) and had more OSA (32.7% vs 15.7%, p=0.011). There were no differences regarding age, gender, body-mass index, history of hypertension, diabetes, chronic kidney disease or heart failure, method of ablation and diagnosis of OSA prior to ablation.

Forty-nine patients (18.7%) had OSA, with only 16 (32.7%) having been diagnosed before ablation. OSA was screened in only 60 cases (31.7%), mostly due to symptoms (76.1%) and not per protocol. Patients with OSA had earlier recurrence of AF after ablation (p Log-rank 0.012) with a hazard two times greater of recurrence, even after adjusting for confounding (p 0.026; hazard-ratio 2.025; confidence interval 95% 1.086–3.775). One year recurrence rate was 31% in patients with OSA (vs 15%). Regarding patients under treatment for OSA prior to ablation, there was no difference in survival (p Log-rank 0.859).

Conclusion

In real-world practice, OSA is still a largely underinvestigated condition that significantly impairs AF control and contributes to worse cardiovascular outcomes. Recurrence was 2 times higher in patients with OSA. No impact of treatment in time to recurrence was found. Efforts must be made to increase screening of this condition in order to improve outcomes. Further studies are needed to clarify the benefits of OSA treatment in AF recurrence.

Funding Acknowledgement

Type of funding sources: None.

Tachydysrhythmias in patients admitted with COVID-19 pneumonia: prevalence and impact on in-hospital mortality

Funding Acknowledgements

Type of funding sources: None.

Background

The COVID-19 pandemic has shifted tremendously the paradigm of hospital care and treatment of cardiovascular (CV) patients. According to most recent evidence, due to its multisystemic impact, COVID-19 may lead to an increased risk of cardiac arrhythmias with subsequently increased morbimortality.

Purpose

Determine the prevalence of tachyarrhythmias in patients admitted with COVID-19, possible predictors and impact on in-hospital mortality.

Methods

A retrospective study of 3475 consecutive patients with COVID-19 pneumonia admitted to our hospital between February 2020 and November 2021 were included. The main outcome was tachyarrhythmias (high ventricular rate (HVR) or new-onset atrial fibrillation (AF), HVR or new-onset atrial flutter (AFL), other supraventricular tachycardias (SVT), ventricular tachycardia (VT) and ventricular fibrillation (VF)). Secondary outcome was in-hospital mortality. Sociodemographic variables and clinical data were recorded. Statistical comparison was made between groups, including logistic regression to determine odds ratios (OR).

Results

A total of 215 patients presented HVR AF (6.31%), 79 of which with new-onset AF (36.74%). 8 patients had HVR AFL (0.23%), 5 VT (0.15%), 4 VF (0.12%) and only 3 patients had a SVT identified (0.09%). Patients with tachyarrhythmias were significantly older (77. 74 ± 11.25 68.94 ± 17.51 years, p <0.001) and had more hypertension (p 0.034), heart failure (HF) (p <0.001), severe valvular heart disease (VHD) (p 0.007), coronary artery disease (CAD) (p 0.031), chronic kidney disease (CKD) (p 0.048) and paroxysmal AF (if previously diagnosed (p 0.001). There were no significant differences regarding gender, dyslipidemia, diabetes, cerebrovascular disease and obstructive sleep apnoea (OSA).

Patients with HF had the highest risk of tachyarrhythmia (OR 3.539; 95% CI 2.666-4.698; p <0.001), followed by severe VHD (OR 1.990; 95% CI 1.192-3.365; p 0.009) and CAD (OR 1.575; 95% CI 1.040-2.386; p 0.032). Older patients or patients with hypertension or CKD were also at an increased risk. Also of note, patients previously diagnosed with paroxysmal AF were more likely to have episodes of HVR AF than the ones with persistent or permanent AF (OR 1.819; 95% CI 1.272-2.602; p 0.001)

Regarding the secondary outcome, patients with tachyarrhythmias during hospital stay had an odd almost 3 times higher of death (OR 2.820; 95% CI 2.151-3.695; p <0.001).

Conclusions

Tachyarrhythmias is a common complication in COVID-19 patients during hospital stay that is significantly linked to higher in-hospital mortality. Patients presenting with high CV disease burden are at particularly significant risk and should be carefully managed.

Prevalence and impact of dysrhythmias in COVID-19 intensive care patients

Funding Acknowledgements

Type of funding sources: None.

Background

The COVID-19 pandemic has had a dramatic impact on clinical practice, amounting to more emergency department and intensive care unit (ICU) admissions. Due to their frequent multiple comorbidities, management in the ICU is challenging. Early studies suggest that cardiac injury is frequent in hospitalized patients with COVID-19, and it is plausible that these patients have a higher risk of cardiac dysrhythmias.

Purpose

To determine the prevalence of dysrhythmias in ICU patients with COVID-19 pneumonia, identify major predictors and determine the impact on in-hospital mortality.

Methods

A retrospective study of 98 consecutive patients with COVID-19 Pneumonia admitted to the ICU of a tertiary hospital in 2020. The main outcome was dysrhythmias (including significant bradycardia, high/slow ventricular rate or new-onset atrial fibrillation (AF) or atrial flutter, other supraventricular tachycardias, ventricular tachycardia and ventricular fibrillation). Significant bradycardia was defined as heart rate lower than 40 or need of treatment. Sociodemographic variables and clinical data were retrieved for each patient, severity scores at admission (Apache II, SOFA and SAPS II), number of days on mechanical ventilation or high-flow oxygen and placement on Venovenous Extracorporeal Membrane Oxygenation (ECMO) or prone position were recorded. Statistical comparison was made between groups, including logistic regression adjusting for confounding variables.

Results

The most frequent arrhythmia was significant sinus bradycardia (28, 28.5%) followed by high ventricular rate AF (14, 14.2%). Patients who had dysrhythmias were older (66.24 ± 10.13 vs 60.85 ± 12.69 years, p 0.024), more severe (SAPS II score 42.55 ± 11.08 vs 35.98 ± 11.26, p 0.006), had more atrial fibrillation (AF) (p 0.022), had higher maximum C-reactive protein (mCRP) (6.56 ± 2.68 vs 6.24 vs 2.86, p 0.009), were mechanically ventilated for a longer time (15.64 ± 13.18 vs 8.92 ± 8.85 days, p 0.004), had longer intubation time (14.52 ± 9.39 vs 8.70 ± 8.21 days, p 0.002) and had higher usage of dexamethasone (p 0.042) and prone position (p 0.016).

When adjusted for confounding variables, prone was the most significant predictor (OR 2.800; 95% CI 1.203-6.516) followed by use of dexamethasone (OR 2.484; 95% CI 1.020-6.050). Days intubated, days on mechanical ventilation, age, mCRP and SAPS II on admission were also predictors of dysrhythmia. Regarding mortality, patients with arrhythmic events had a tendency for greater in-hospital death (OR 2.440; 95% CI 0.950-6.310; p 0.065).

Conclusions

COVID-19 ICU patients are a subset of patients at risk of cardiac arrhythmias. Use of prone position was the main contributor to these events, but clinical history, severity and treatment may also play an important role. Efforts must be made to optimize ventilatory support and treatment in order to reduce the risk of dysrhythmias.

Impact of the COVID-19 pandemic on emergent pacemaker implantation during lockdown and its aftermath

Background

COVID-19 was first considered a pandemic on the 11th of March of 2020 by the World Health Organization. Its impact comprised not only the direct consequences of the disease but a decrease in the follow-up and interventions of patients with cardiovascular (CV) disease. In Portugal and the World, the consequences of this complex paradigm shift on emergent pacemaker implantation rates during and after this pandemic is largely unknown.

Purpose

We sought to analyse the impact of COVID-19 pandemic on emergent pacemaker implantation rate and patient profile in a tertiary hospital during the first Portuguese lockdown and subsequent post-lockdown period.

Methods

We retrospectively reviewed the clinical profile of patients who had pacemakers implanted in our hospital in an urgent/emergent setting from March 18, 2020 to May 17, 2020 (lockdown) and May 19 to July 17, 2020 (post-lockdown). This data was then directly compared to the homologous periods from the year before (H1 and H2, respectively).

Results

A total of 180 patients submitted to emergent pacemaker implantation were included.

The cohort was comprised of 29 patients who had a pacemaker implanted during lockdown, 60 post-lockdown, 38 in H1 (+31% vs lockdown) and 53 in H2. Average age and gender proportion were similar for all groups.

When comparing lockdown and post-lockdown periods, the number of cases significantly increased in the second period (+106.9%) and there was a tendency for a higher number of temporary pacemaker use (3.4% vs 16.7%; p=0.076). Patients admitted during lockdown were 7.57 times more likely to present with hypotension/shock (odds ratio (OR) 7.57; p=0.013).

Regarding lockdown and its homologous 2019 period, there was a decrease in the number of patients admitted (−23.7%). Again, there was a higher tendency for hypotension on presentation during lockdown (p=0.054).

In comparison to its homologous 2019 period, post-lockdown saw a slight increase in the number of patients (+13.2%) and more patients presented with bradycardia (16.7% vs 3.8%; p=0.026).

Also of note, no patients were admitted to the emergency department during lockdown for anomalies detected on ambulatory tests (Holter, electrocardiogram or implanted loop recorder).

Conclusion

During lockdown, clinical presentation was generally more severe, with a greater number of patients presenting with hypotension/shock. In addition, there appears to be a lockdown effect on emergent bradyarrhtmias admissions in the post-lockdown period with a profound impact: higher admission rates and more severe presentations including a higher need of temporary pacemaker. Patients with symptoms suggestive of bradyarrhythmias should be advised to present promptly regardless of the pandemic.

Funding Acknowledgement

Type of funding sources: None. Pacemakers during lockdown/post-lockdownPacemakers implanted by diagnosis

Impact of haemodialysis in the development of atrial fibrillation: a retrospective cross-sectional study

Background

Chronic kidney disease (CKD) is a very common co-morbidity in patients with cardiovascular disease, particularly in those with atrial fibrillation (AF). There is an increasing number of patients on haemodialysis who have AF and its impact is not fully understood.

Purpose

To assess the prevalence of AF in patients on haemodialysis, trying to identify predictors of AF development.

Methods

Unicentric, retrospective study including all patients admitted to the Nephrology ward from October 2020 to December 2020 who had CKD. Cardiovascular risk factors, known cardiac disease, time on haemodialysis, type of vascular access and demographic data were analysed. The control group was comprised of hospitalized CKD patients who were not on renal replacement therapies.

Results

A total of 126 patients were included, 57 on dialysis. Mean age for the renal replacement therapy group was 71.07±15.68 years and for the control group was 72.59±14.74 years old (p=0.575). There was an increased proportion of patients with type 2 diabetes mellitus in the control group (39 vs 20, p=0.021). No statistically significant differences were found regarding hypertension, heart failure, coronary disease or sleep apnoea between groups.

The prevalence of AF was similar in both the haemodialysis and the control group (26.3% vs 24.6%, p=0.829). Age, heart failure and coronary disease were significant risk factors for AF, irrespective of the studied group (p<0.05). There was also a significant correlation between time on dialysis and a greater likelihood of presenting AF (p<0.05). There was no correlation with type of vascular access.

Using the Youden index, an age of 80.5 years was determined as the cut-off for an increased prevalence of AF, irrespective of the study group (sensitivity of 66.7%; Specificity of 78.8%). Using ROC curves, an area under the curve (AUC) of 0.74 was obtained for age and the likelihood of AF (figure 1). Regarding time on dialysis, a cut-off point of 4.5 years was obtained with an AUC of 0.67 (sensitivity of 73% and specificity of 68.7%) (figure 2).

Conclusion

AF is very common in patients with end-stage renal disease, with a prevalence estimated to be 4 times greater than the general population. Our results suggested that, while haemodialysis may not be a risk factor for AF by itself, a longer time on haemodialysis may contribute to its onset. Age was also a contributing factor. Further prospective studies with more homogeneous groups are needed to clarify its role as an independent risk factor for AF.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Age as predictor of AFFigure 2. Time on dyalisis as predictor of AF

Circulating endothelial progenitor cells as predictors of long-term cardiovascular mortality after myocardial infarction: which definition should we use?

Background

Endothelial progenitor cells (EPCs) are bone marrow-derived cells that play a crucial role in vascular repair after an acute myocardial infarction (AMI). Recent studies suggest that circulating EPCs levels may be useful as a surrogate biomarker for cardiovascular (CV) events. Nevertheless, the lack of a consensual definition and phenotypic characterization of EPCs hampers its use in clinical practice. CD34+KDR+, CD45dimCD34+KDR+ and CD34+CD133+KDR+ are among the most used antigenic phenotypes to define circulating EPCs but the best phenotype to predict CV outcomes remains to be determined.

Purpose

To determine the EPCs' surface phenotype that best predicts long-term CV death after an AMI, and to evaluate its optimal cut-off point.

Methods

One-hundred AMI patients were prospectively enrolled in the study. Circulating EPCs were quantified through high-performance flow cytometer within the first 24 hours of admission using different surface markers combinations allowing to simultaneously compare three EPCs definitions: 1) CD34+KDR+, 2) CD45dimCD34+KDR+, 3) CD34+CD133+KDR+. Mean follow-up time was 8.0±2.2 years.

Results

The mean age of our population was 59.7±11.0, the majority of patients were male (90%), 65% had ST-elevation myocardial infarction (STEMI) and 35% non-ST segment elevation myocardial infarction (NSTEMI). Diabetes mellitus was present in 38% and hypertension in 67% of the studied sample. During the long-term follow-up, 34 patients had re-admissions due to cardiovascular causes, 11 of them for AMI. Thirty-one patients had major adverse cardiovascular events (MACE) and 19 died.

Using ROC curves, the CD34+KDR+ phenotype showed the biggest area under the curve regarding prediction of CV mortality (0.722; p=0.010; confidence interval 95% (CI95%): 0.554 to 0.890). Patients with lower levels of EPCs according to this definition (≤0.022%) are 7 times more likely to die from CV causes at any time (hazard ratio = 7.55; p=0.008; CI95% 1.69 to 33.83).

Conclusion

The CD34+KDR+ phenotype appears to be the best definition of circulating EPCs for predicting long-term CV mortality after AMI. Further studies with larger samples are needed to clarify the optimal cut-off point for determining patients at risk and its role in everyday Cardiology.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Bolsa de Estudo João Porto da Sociedade Portuguesa de Cardiologia CD34+KDR+ as a predictor of CV death