Prevalence of modifiable risk factors and related poor cardiovascular outcomes following atrial fibrillation ablation

Background

Atrial fibrillation (AF) has become a global epidemic. Early catheter ablation and therapies modifying risk factors (RF) have been shown to improve outcomes of AF ablation. However, the time invested in pursuing risk factor modification may delay ablation, which could negate the procedural benefit.

Purpose

This study sought to investigate the prevalence and impact of potentially modifiable RF among AF patients undergoing catheter ablation in clinical practice.

Methods

This retrospective study included 724 consecutive patients undergoing AF ablation at a tertiary care center from 2012–2019. Pre-specified modifiable risks were examined, including the time from AF diagnosis to ablation, fluctuation/increase in BMI >5% prior to ablation, mean systolic/diastolic blood pressure >125/80 mmHg, obstructive sleep apnea with CPAP noncompliance, hyperlipidemia without statin therapy, tobacco use, excessive alcohol use, and diabetes mellitus with hemoglobin A1c (HbA1c) >6.5%. The primary outcome was a composite of recurrent atrial arrhythmias, cardiovascular (CV) hospitalizations and mortality following AF ablation. A multivariate analysis was performed.

Results

The mean age was 61±10 years old, 32.5% were female and 72.2% had persistent AF. Many study patients had modifiable RF, ranging from 4.7% with excessive alcohol use to 64.0% experiencing delayed AF ablation. The mean time from AF diagnosis to ablation was 4.7 years. During a mean follow-up of 1.6 years after ablation, 467 (64.5%) patients met the primary outcome. Independent RF for the primary outcome were an increase/fluctuation in BMI >5% (adjusted hazard ratio [AHR] 1.31, 95% confidence interval [CI] 1.07–1.60; P=0.008), diabetes with HbA1c >6.5% (AHR 1.50, 95% CI 1.09–2.03; P=0.014) and hyperlipidemia without statin therapy (AHR 1.30, 95% CI 1.08–1.57; P=0.005). Delayed AF ablation over 1.5 years did not alter the outcome, Figure 1.

Conclusion

Substantial portions of patients undergoing AF ablation have potentially modifiable RF. Increased or fluctuating BMI, diabetes with HbA1c >6.5%, and hyperlipidemia not treated with statin therapy portend an increased risk of recurrent atrial arrhythmia, CV hospitalizations and mortality. These findings underscore an importance pursuing RF management in patients with AF to reduce adverse outcomes after ablation.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Jensen Family Research Sponsorship at the University of Nebraska Medical Center

Pre-ablation interatrial conduction delay or block predicts atrial fibrillation recurrence after ablation among obese patients

Funding Acknowledgements

Type of funding sources: None.

Background

Obesity is associated with greater risk of atrial fibrillation (AF) recurrence post-ablation and higher incidence of conduction delay compared to non-obese patients. Pre-ablation P-wave duration (PWD) and morphology (PWM) indicating interatrial delay are easily assessed in the clinic and may predict AF recurrence post-ablation in these patients.

Purpose

Evaluate the predictive value of PWD and PWM on AF recurrence post-ablation in obese patients.

Methods

Pre-ablation PWD and PWM (negative P-wave in lead II or III) were analyzed on consecutive patients with BMI ≥30 kg/m2 who underwent initial AF ablation from 2012–19. The primary outcome was recurrent AF after a 3-month post-ablation blanking period. Multivariate analysis adjusted for baseline characteristics was performed.

Results

For 205 patients (61.0±9.5 years old, 39.0% female), mean BMI was 36.9±5.7 kg/m2 and 71.7% had persistent AF pre-ablation. Recurrent AF post-ablation occurred in 115 (56.1%) during a median follow up of 491 (270, 1001) days. PWD >130 ms was significantly associated with higher AF recurrence (AHR of 1.62, 95%CI 1.04-2.57, p=0.03) after adjusting for age, persistent AF and left atrial volume index (LAVI). In a subgroup with LAVI <42 mL/m2 (n=112), PWD >130 ms and negative P-waves in lead II or III were independently associated with increased risk of recurrent AF (AHR 2.06, 95%CI 1.12-3.91; p=0.019 and AHR 1.94, 95% CI 1.00-3.56; p=0.05, respectively) (Figure 1).

Conclusion

AF recurred in >50% of obese patients within 1.5 years of ablation. Pre-ablation PWD >130 ms and negative P-waves in lead II or III independently predicted recurrent AF post-ablation in this cohort of obese patients. These easily assessed findings add predictive value to other risk factors.

Poor glycemic control in diabetic patients increases the risk of recurrent atrial arrhythmia and cardiovascular hospitalizations among morbidly obese patients undergoing atrial fibrillation ablation

Background/Introduction

Obesity and atrial fibrillation (AF) coexist and share multiple cardiovascular risk factors. Lifestyle modifications can reduce AF burden in obese patients. However, the time invested in pursing lifestyle changes may delay AF ablation, which could negate the procedural benefit.

Purpose

To examine the effects of lifestyle modifications and the timing of catheter ablation on morbidly obese patients with AF.

Methods

This retrospective study included 217 consecutive AF patients with a body mass index (BMI) ≥35 kg/m2 undergoing AF ablation at a tertiary care center from 2012 to 2019. Modifiable risks were examined, including the time from AF diagnosis to ablation, fluctuation of BMI >5% or an increase in BMI >3% prior to ablation, mean systolic blood pressure >130 mmHg or diastolic blood pressure >80 mmHg, obstructive sleep apnea with CPAP noncompliance, hyperlipidemia without statin therapy, tobacco use, excessive alcohol use, and diabetes mellitus with hemoglobin A1c (HbA1c) ≥6.5%. The primary outcome was a composite of recurrent atrial arrhythmias and cardiovascular (CV) hospitalizations following AF ablation. A multivariate analysis adjusting for age, gender and modifiable risks was performed.

Results

The mean age was 61±9 years old, 58% were female and 45% had persistent AF. A substantial portion of the study patients had modifiable risk factors, ranging from 2.7% with excessive alcohol use to 67.3% experiencing delayed AF ablation, Figure 1. The median time from diagnosed AF to ablation was 1.3 years. During a mean follow-up of 2.9 years after AF ablation, 136 (62.7%) patients met the primary outcome. Only HbA1c ≥6.5% was an independent risk factor with adjusted hazard ratio of 1.57, 95% confidence interval 1.02–2.36, P=0.0412, Figure 2A. Delayed AF ablation did not alter the outcome, Figure 2B. There was no interaction between time of ablation and HbA1c ≥6.5% (P=0.67).

Conclusion

Substantial portions of morbidly obese patients undergoing AF ablation have potentially modifiable risk factors. Poor glycemic control with HbA1c ≥6.5% predicts an increased risk of recurrent atrial arrhythmias and CV hospitalizations, while delayed AF ablation does not. This finding underscores an importance of optimizing HbA1c in morbidly obese patients with AF to reduce adverse outcomes after ablation.

Funding Acknowledgement

Type of funding sources: None.

Potential risk of vasovagal syncope for motor vehicle driving

Vasovagal syncope is the most common cause of syncope, but its risk for driving remains uncertain. We analyzed the clinical characteristics of patients who had syncope during driving and subsequently underwent the head-up tilt test (HUTT). Of the 245 consecutive patients undergoing HUTT, 23 (9%) had > or =1 episode of syncope during driving. HUTT was positive in 19 (group A) and negative in 4 (group B) patients. No patient had structural heart disease. In group A, the driving incident occurred on the first syncope in 3 patients, and the other 16 patients had 1 to 4 episodes of prior syncope not associated with driving. In group B, the driving incident occurred on the first syncope in 1 patient, and the other 3 patients had prior syncope (3 episodes in each) not associated with driving. Seven group A and 1 group B patients had 2 syncope-related driving incidents, and the remaining patients had only 1 syncope-related driving incident. The syncope-related driving incidents caused personal injury in 7 group A and 2 group B patients. One incident in 1 group A patient caused the death of another driver. After HUTT, all but 1 patient in group A received medical treatment and only 1 patient in group B received empirical beta-blocker therapy. During the follow-up of 51+/-26 months, 1 patient died and another was lost to follow-up. Of the remaining patients, 4 patients had recurrence of syncope and 2 patients had presyncope in group A. One of these patients had another syncope-related driving incident. No group B patient had syncope recurrence. A second etiology of syncope was never found in any patient. We conclude that vasovagal syncope during driving is not uncommon in patients referred for syncope evaluation. Early medical attention to patients with vasovagal syncope may help reduce syncope-related driving incidents.

Usefulness of ibutilide in facilitating successful external cardioversion of refractory atrial fibrillation

We repeated direct-current cardioversion of atrial fibrillation after ibutilide injection in patients who failed conventional cardioversion. Eleven of 12 patients (92%) had successful cardioversion and avoided the need for internal cardioversion.

The mean ventricular fibrillation cycle length: a potentially useful parameter for programming implantable cardioverter defibrillators

In programming the implantable cardioverter defibrillator (ICD), the ventricular tachycardia (VT) detection cycle length (CL) is based on the CL of the documented tachycardia but the ventricular fibrillation (VF) detection CL is set arbitrarily. Appropriate programming of VF detection may not only reduce the incidence of inappropriate ICD shocks for non-VF rhythms but can also avoid the fatal underdetection of VF. The mean VFCL may provide a useful parameter for optimal ICD programming for VF detection if it is reproducible. This study examined the intrapatient reproducibility and interpatient variation of the mean VFCL in 30 ICD patients (25 men and 5 women, mean age 63 +/- 13 years). A total of 210 VF episodes (7 +/- 4 per patient, range 3-17) induced by T-wave shocks (166) or AC (44) at the ICD implant (30 patients) and the predischarge test (12 of 30 patients) were analyzed. The mean VFCL was calculated from the stored V-V intervals in the ICDs. Although the mean VFCL varied significantly from 171 +/- 6 to 263 +/- 11 ms (P < 0.01) among different patients, it was reproducible among different VF episodes in an individual patient (maximal variation 4-50 ms, P > 0.05). The mean VFCL was not significantly different between patients with and without antiarrhythmic drugs (210 +/- 32 vs 210 +/- 23 ms, P > 0.05) and was correlated with the ventricular effective refractory period (r = 0.5, P < 0.05). The mean VFCL varies greatly among different patients but remains reproducible in an individual patient, suggesting that the mean VFCL may serve as a reference for ICD programming of VF detection.

Causes and consequences of discontinuation of the implantable cardioverter-defibrillator therapy in non-terminally ill patients

Infection and implantable cardioverter-defibrillator shocks are important contributing factors to discontinuation of cardioverter-defibrillator therapy in non-terminally ill patients. These patients are at a high risk of sudden cardiac death despite continued antiarrhythmic drug therapy.

Evaluation and management of atrial fibrillation in the emergency department

AF is the most common sustained cardiac arrhythmia. Recognition and appropriate management of AF is important to optimize care of concurrent medical problems and prevent long-term consequences. DC cardioversion under sedation should be performed in patients with pulmonary edema, angina, or hypotension. Ventricular rate control is the first choice in stable patients with rapid ventricular rate. Anticoagulation should be considered in all patients with AF duration < 48 hours, except for those under 65 years old and having no other risk factors of stroke. Recent data imply that early attempts at cardioversion may increase success rates and decrease AF recurrence rates. Thus, transesophageal echocardiogram-guided early cardioversion may become more widely used.

The long-term use of zidovudine in patients with severe immune-mediated thrombocytopenia secondary to infection with HIV

Various treatments for HIV-related thrombocytopenia have been reported. Since etiologies of the thrombocytopenia may differ with regard to risk group treatment outcomes may also vary. We have recently studied the long-term use of zidovudine in individuals with sexually transmitted HIV infection and severe thrombocytopenia. Twenty-five men, median age 34 years (range, 23-51 years), were treated with zidovudine (1000 mg/day) for a median duration of 12 months (range, 2.5- less than 26 months). Nineteen patients (76%) had had episodes of symptomatic bleeding secondary to thrombocytopenia prior to study entry. All patients bleeding symptoms resolved with therapy. Six (24%) achieved a complete response, with normalization of platelet counts, while 11 patients (44%) achieved a partial response, giving an overall response rate of 68%. The median time to partial or complete normalization of platelet counts was 12 weeks (range, 4-62 weeks). Toxicities were minimal during the study period. Only one patient developed an AIDS-defining diagnosis while on therapy. We conclude that patients with sexually transmitted HIV infection and immune thrombocytopenia may need a prolonged period of therapy with zidovudine to achieve a platelet response. Other treatment modalities may be required for the 30% of patients who do not respond to zidovudine.