Long-term follow-up after atrioventricular nodal ablation and pacing: low incidence of sudden cardiac death

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.

Acute and long-term outcomes of left-sided atrioventricular node ablation in patients with atrial fibrillation

PURPOSE

To present our experience regarding acute and long-term outcomes of left-sided atrioventricular node (AVN) ablation in patients with atrial fibrillation (AF).

METHODS

A total of 47 patients with AF in whom left-sided AVN ablation via retroaortic approach as a first-line approach were enrolled in this retrospective study. Indications for AVN ablation were high ventricular rate refractory to medical therapy, inappropriate implantable cardioverter defibrillator (ICD) shocks, or loss of cardiac resynchronization therapy (CRT) pacing. Both acute and long-term outcomes were assessed for all participants.

RESULTS

Left-sided AVN ablation was successfully performed in 46/47 (98%) patients without any procedural complication. In the remaining 1 patient (2%), right-sided AVN ablation was performed. No mortality was observed within 30 days of the procedure. Upgrade to CRT was performed in 9 (19%) of the patients. During the median 22.5 months of follow-up, all-cause mortality was 25%. Device interrogations on the last clinical visit revealed complete AV block and intrinsic ventricular rate of < 40 bpm in all patients.

CONCLUSION

Left-sided AVN ablation is a safe and effective procedure without recurrence during long-term follow-up.

Sudden death and its risk factors after atrioventricular junction ablation and pacemaker implantation in patients with atrial fibrillation

BACKGROUND

Although sudden death (SD) is a rare complication after atrioventricular junction (AVJ) ablation and permanent pacemaker implantation, the risk factors leading to this SD remain unknown. The purpose of this study was to investigate SD and its risk factors after ablate-and-pace strategy for rate control in atrial fibrillation (AF) patients during long-term follow-up.

HYPOTHESIS

METHODS: From January 2005 to December 2009, we enrolled into this study 517 AF patients with AVJ ablation and right ventricular pacemaker implantation. Patients were divided into 2 groups, SD and non-SD. Cox proportional hazards models were used to assess potential risk factors for overall mortality and SD.

RESULTS

During a mean follow-up of 25.8 ± 18.6 months (range, 3 days to 63.8 months), 53 patients died (15 with SD). Cox proportional hazards models showed that the presence of congestive heart failure, New York Heart Association functional class, chronic renal failure, and nonsustained ventricular tachycardia were risk factors that predicted overall mortality. For SD, the presence of dilated cardiomyopathy and mitral stenosis were associated risk factors. SD was exclusively seen in patients who had narrow QRS complex or right bundle branch block prior to AVJ ablation and pacemaker implantation; SD was not seen in any patient with preexisting complete left bundle branch block.

CONCLUSIONS

Dilated cardiomyopathy, mitral stenosis, and baseline QRS morphology should be examined as potential risk factors for SD after AVJ ablation and pacemaker implantation.

Mortality After Atrioventricular Nodal Radiofrequency Catheter Ablation With Permanent Ventricular Pacing in Atrial Fibrillation

Background—

Atrioventricular nodal radiofrequency ablation (AVNA) with permanent ventricular pacing can be used to control rate in patients with atrial fibrillation (AF). However, long-term outcomes after AVNA are uncertain, especially in light of irreversible pacemaker dependence.

Methods and Results—

We examined 9122 consecutive patients with AF. The outcomes in 453 patients with AVNA (26% of whom underwent an implantable cardiac defibrillator implant and 37% underwent cardiac resynchronization therapy implant) were compared with AF patients without AVNA after propensity score 1:1 matching. During follow-up in the propensity-matched cohort (2.41±3.23 years, median 1.23, quartiles 0.33–3.12), 100 patients died (yearly rate of death 6.6%). Mode of death was available in 86% of patients, which was cardiovascular in 67% of the patients (related to heart failure in 38%, sudden death in 5%, and other cardiovascular reason in 24%) and noncardiovascular in 33%. AVNA in patients with AF was associated with a lower risk of mortality (odds ratio 0.47, 95% confidence interval, 0.29–0.77; P =0.003), a lower risk of cardiovascular mortality (odds ratio =0.41, 95% confidence interval 0.23–0.73; P =0.003), and nonsignificant lower risk of stroke and thromboembolic events (odds ratio =0.61, 95% confidence interval 0.36–1.06; P =0.08).

Conclusions—

In sick AF patients with multiple comorbidities, AVNA with permanent ventricular pacing for rate control seems safe during follow-up and may be associated with lower mortality.

Effect of pacing method on risk of sudden death after atrioventricular node ablation and pacemaker implantation in patients with atrial fibrillation

BACKGROUND

Sudden death may occur after radiofrequency catheter ablation of the atrioventricular node (AVN) and permanent pacemaker implantation. It is unclear whether a faster initial heart rate with gradual rate reduction decreases the risk of sudden death.

OBJECTIVE

To evaluate the effects of initial pacing at a faster rate after AVN ablation, with a gradual rate decrease over 3 months, on the rate of sudden death in patients with atrial fibrillation.

METHODS

We compared the rate of likely or possible procedure-related sudden death in 2 groups of patients who had AVN ablation and pacemaker implantation. The study cohort was treated between January 2005 and December 2009, and pacemakers were programmed to a lower rate of 90 beats/min after the procedure, with a monthly decrement of 10 beats/min until 60 beats/min was reached. The control group was treated between July 1990 and December 1998 when pacemakers were programmed to a lower rate of 60 beats/min immediately after ablation.

RESULTS

The study cohort included 520 patients (mean age 73.6 ± 10.3 years), and the control cohort comprised 334 patients (mean age 68.1 ± 1.1 years). Sudden death deemed likely or possibly related to ablation and pacemaker implantation occurred in 1 patient in the study cohort (0.2%) and in 7 patients (2.1%) in the control group (P = .007).

CONCLUSIONS

Sudden death was significantly decreased in the study cohort compared to controls. The faster lower pacing rate immediately after AVN ablation with a gradual decrease is a plausible mechanism for the improved clinical outcome.

Ablate and Pace: Is There Still a Role?

Despite the development of newer drugs and procedures to improve rhythm control, there is still a place for ablation of the atrioventricular junction (AVJ) in the management of selected patients with AF who are refractory to medical therapy, to improve quality of life, prevent ventricular dysfunction, and to optimize cardiac resynchronization therapy. We review all aspects of the "ablate and pace" strategy, from its history to patient selection, technique, outcomes and applications, and identify the need for randomized clinical trials to address some of the remaining questions regarding its application in some groups of patients.

The Australian Intervention Randomized Control of Rate in Atrial Fibrillation Trial (AIRCRAFT)

OBJECTIVES

The Australian Intervention Randomized Control of Rate in Atrial Fibrillation Trial was a multicenter trial of atrioventricular junction ablation and pacing (AVJAP) compared with pharmacologic ventricular rate control (medication [MED]) in patients with mild to moderately symptomatic permanent atrial fibrillation (AF).

BACKGROUND

There have been very few prospective randomized trials, undertaken in highly symptomatic patients, comparing AVJAP with pharmacologic methods of ventricular rate control for patients with permanent AF.

METHODS

There were 99 patients (70 men, mean age 68 +/- 8.6 years) at five centers. Forty-nine patients were randomized to AVJAP while 50 patients were randomized to pharmacologic control. The primary end point was cardiac function measured by echocardiography and exercise tolerance. The secondary end points were ventricular rate control, evaluated by 24-h ambulatory electrocardiographic monitoring, and quality of life. Data were collected at randomization and then at one month, six months, and 12 months post-randomization.

RESULTS

At 12 months follow-up there was no significant difference in left ventricular ejection fraction (AVJAP: 54 +/- 17%; MED: 61 +/- 13% [p = ns]) or exercise duration on treadmill testing (AVJAP: 4.1 +/- 2 min; MED: 4.6 +/- 2 min [p = ns]); however, the peak ventricular rate was lower in the AVJAP group during exercise (112 +/- 17 beats/min vs. 153 +/- 36 beats/min, p < 0.05) and activities of daily life (117 +/- 16 beats/min vs. 152 +/- 37 beats/min, p < 0.05). The CAST quality-of-life questionnaire revealed that patients in the AVJAP group had fewer symptoms at six months (p = 0.003) and at 12 months (p = 0.004). The observed relative risk reduction in symptoms at 12 months was 18%. Global subjective semiquantitative measurement of quality of life using the "ladder of life" revealed that the AVJAP group reported a 6% better quality of life at six months (p = 0.011).

CONCLUSIONS

In this trial, AVJAP for patients with mild to moderately symptomatic permanent AF did not worsen cardiac function during long-term follow-up, and quality of life was improved.

Selective atrionodal input ablation for induction of proximal complete heart block with stable junctional escape rhythm in patients with uncontrolled atrial fibrillation

BACKGROUND

The study tests the hypothesis that ablating all inputs to the atrioventricular (AV) node can result in complete heart block with stable junctional escape rhythm.

METHODS AND RESULTS

We attempted atrionodal input ablation in 76 consecutive patients with uncontrolled atrial fibrillation. Fast and slow pathways were first ablated. If there was no AV block, additional energy applications were done between fast and slow pathway locations. The patients were followed for 42 +/- 11 months. Group I (n = 57) comprised patients with complete heart block and junctional escape rhythm (53 +/- 4 beats/min) at the end of the procedure. The escape rhythm remained stable throughout follow-up. Group II (n = 15) were patients who failed the stepwise atrionodal input ablation and required AV junctional ablation guided by His bundle potential to achieve complete heart block. Four patients showed a slow escape rhythm after ablation (33 +/- 4 beats/min). Others had no escape rhythm. All 15 pts remained pacemaker dependent. The total death rate of groups I and II was 18/57 (31.6%) vs 10/15 (66.7%), respectively (p < 0.02). These differences could not be explained by a difference of left ventricular ejection fraction (0.42 +/- 0.07 vs 0.41 +/- 0.04, respectively, p = NS).

CONCLUSIONS

(1) In most patients, ablation of both fast and slow pathways did not result in complete heart block, indicating the presence of multiple atrionodal inputs. (2) Ablation of all atrionodal inputs may result in complete heart block with stable junctional escape rhythm. (3) As compared with AV junctional ablation, atrionodal input ablation was associated with a lower mortality rate on long-term follow up.

Transient proarrhythmic state following atrioventricular junction radiofrequency ablation: pathophysiologic mechanisms and recommendations for management

The induction of complete heart block by radiofrequency ablation of the atrioventricular junction combined with pacemaker implantation has become an established therapy for rate control in patients with atrial fibrillation who are unresponsive to drugs. Reports of ventricular arrhythmias and sudden death after ablation have, however, raised concerns about safety. Ventricular arrhythmias are usually polymorphic and related to a phase of electrical instability due to an initial prolongation and then slow adaptation of repolarization caused by the change in heart rate and activation sequence. Structural heart disease, and other factors that predispose for the acquired long QT syndrome, seem to add to the risk. Ventricular activation and repolarization stabilize during the first week after the procedure. Routine pacing at 80 beats per minute during this phase is recommended, as well as in hospital monitoring for at least 48 hours. Patients with high-risk features for arrhythmias, such as congestive heart failure or impaired left ventricular function, may require pacing at higher rates. Adjustment of the pacing rate-although rarely below 70 beats per minute-is usually undertaken after a week in most patients, preferably after an electrocardiographic evaluation for repolarization abnormalities at the lower rate.

Sudden death after radiofrequency ablation of the atrioventricular node in patients with atrial fibrillation

OBJECTIVES

We evaluated the incidence and predictors of sudden death after atrioventricular (AV) node ablation and pacemaker implantation.

BACKGROUND

Sudden death may occur after radiofrequency catheter ablation of the AV node and pacemaker implantation in patients with atrial fibrillation (AF). Whether it is related to the procedure or to pre-existing heart disease remains unclear.

METHODS

All patients who had radiofrequency catheter ablation of the AV node and pacemaker implantation for rate control of medically refractory AF were identified retrospectively and observed prospectively. All patients with sudden death after ablation were identified. The relationship between the procedure and sudden death was defined on the basis of the time between the two as "likely," "possibly" or "unlikely."

RESULTS

Of 334 consecutive patients with AF who underwent AV node ablation, nine had sudden death after the ablation. Four patients (1.2%) had sudden death likely related to the procedure: in 3 patients, arrest occurred within 48 h after the procedure; in one patient, arrest occurred four days after the procedure. In three other patients (0.9%), sudden death was possibly related to the procedure because the event occurred within three months afterward. The remaining two deaths were unrelated to the procedure. Diabetes, New York Heart Association functional class (>or=II), preprocedure ventricular arrhythmia, mitral or aortic stenosis, aortic regurgitation and chronic obstructive pulmonary disease were independent predictors for sudden death.

CONCLUSIONS

Sudden death likely or possibly related to catheter ablation occurred in 7 of 334 patients (2.1%). Risk of sudden death is highest within two days after the procedure.

Atrial Fibrillation

The conversion of atrial fibrillation (AF) to normal sinus rhythm should be attempted in patients who present with this condition, as long as the cure is not worse than the disease itself. In young patients with normal hearts, AF has a small impact on morbidity and mortality. The primary indication for conversion in this population is often symptoms. In contrast, in patients with diseased hearts or who are older than 65 years, maintaining sinus rhythm may have a favorable impact on stroke risk, ventricular function, and symptoms. In the absence of normal sinus rhythm, these patients should receive anticoagulants. Rate control is the preferred first-line strategy for asymptomatic patients and patients presenting with a history of long-standing, persistent AF, making conversion and maintenance of sinus rhythm unlikely. Rate control may be used in patients who develop AF during an acute systemic illness, which will likely terminate with time or therapy. Conversion to sinus rhythm should be considered in patients with a first episode of AF, as unconverted AF tends to perpetuate itself. Conversion can be attempted if the duration of AF is less than 48 hours or if the patient has received anticoagulants when the duration is not known. Other indications for cardioversion are prolonged episodes in patients with otherwise infrequent episodes of paroxysmal AF, and in patients who refuse to take anticoagulants or in whom anticoagulation is contraindicated. After the patient is converted to sinus rhythm, the decision to initiate chronic drug therapy should be based on the presence of other cardiac and medical diseases that increase the risk of recurrence and serious symptoms in case of recurrence (such as hypertrophic cardiomyopathy or mitral stenosis). It is acceptable to manage patients with new-onset AF and normal cardiac function with cardioversion alone and not initiate chronic antiarrhythmic therapy afterwards. However, in patients with abnormal hearts (coronary artery disease, hypertensive or mitral valvular heart disease, and cardiomyopathy) AF is likely to recur, and such patients should be placed on antiarrhythmic medication.