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The relationship between cardiac arrhythmias with both obstructive sleep apnea (OSA) and central sleep apnea (CSA) is increasingly being recognized. This association is especially well established between sleep apnea and atrial fibrillation.
The interaction seems to go beyond the co-existence of the two disorders due to shared risk factors. The mechanism between ventricular arrhythmias and sleep apnea is less well described and is restricted mostly to observations about obstructive sleep apnea contributing to ventricular arrhythmias.
A 63-year-old male with history of coronary artery bypass graft surgery with decreased left ventricular ejection fraction (LVEF) of 45% was noted to have frequent monomorphic premature ventricular contractions (PVCs), with a burden of 40% (on amiodarone and metoprolol). In addition, he also was diagnosed with severe OSA and had complaints of fatigue, non-restorative sleep. The EKG before ablation is seen in figure 1. He underwent PVC mapping and ablation procedure. The PVCs were mapped and ablated with immediate suppression at the interleaflet triangle below the left and right coronary cusps. The PVC burden 3 months post ablation on a repeat 2- week event recorder was noted to be 2%, corresponding to improved symptoms. Notably, there was no change in LVEF. The patient’s amiodarone was stopped at this point. After 1 year, the LVEF continued to remain in the initial range.
Before the ablation procedure, downloads of patient’s positive airway pressure (PAP) machine revealed significant elevation in periodic breathing, as noted in figure 2a with subsequent improvement as seen in figure 2b. The percentage of periodic breathing was 21.5% which decreased to 6.1% after ablation. Before ablation apnea hypopnea index (AHI) was 4.7 which reduced to 2.2 after ablation in the 4-week period post ablation (before CPAP prescription, the AHI was 31.5). The AHI 1 year was 1.5 with continued patient reported improvement in sleep quality. The representative periodic Cheyne Stokes breathing pattern prior to ablation on PAP waveform review can be seen in figure 3a. The improvement in the periodic breathing pattern post ablation is seen in the corresponding representative tracing in figure 3b. Patient reported improvement in quality of sleep, fatigue and daytime functioning. Other risk factors for OSA during follow up such as neck circumference, sleep position, and alcohol intake were unchanged.
Figure 2Waveform data obtained from the patient’s CPAP machine. The x-axis is the timeline. Figure 2a (left) shows sleep parameters in the 1 month immediately before PVC ablation. Figure 2b (right) shows sleep parameters 1 month immediately after PVC ablation.
Figure 3The sample waveforms before (above) showing periodic breathing/Cheyne Stokes pattern and after (below) PVC ablation shows an improvement in periodic breathing. Note the background is marked as green when periodic breathing is detected.
Our patient was being treated for OSA with PAP, and the machine downloads revealed episodes of periodic breathing concerning for coexisting central sleep events. CSA diagnosis was not made on a formal sleep study, but waveform download as shown in Figure 3a was highly concerning for Cheyne Stokes ventilation pattern. Central sleep apnea is diagnosed in patients with Cheyne Stokes breathing who meet polysomnogram criteria and have the classic crescendo-decrescendo pattern. Therefore, periodic breathing could be considered a surrogate for central sleep apnea. The periodic breathing improved significantly in our patient immediately after PVC ablation as evidenced by improved AHI and percent of periodic breathing.
Ablation of atrial fibrillation has been shown to improve CSA, and treating sleep apnea associated with decreased atrial fibrillation burden.
Prevalence and clinical characteristics of obstructive- and central-dominant sleep apnea in candidates of catheter ablation for atrial fibrillation in Japan.
A similar reciprocal therapeutic association between ventricular arrhythmias and sleep apnea has not been described.
The improvement in sleep apnea after PVC ablation is likely due to factors unrelated to LVEF as this parameter had not improved in our patient. The immediate improvement in sleep apnea following PVC ablation also suggests a mechanism related to improved acute hemodynamics positively affecting sleep apnea.
Central sleep apnea is closely associated with heart failure and elevated pulmonary capillary wedge pressure (PCWP).
The fact that patient’s PVCs were associated with VA dissociation could lead to exacerbation of this phenomenon. Other possible mechanisms to explain the improvement could be related to improved cardiac output after PVC ablation. Interventions that improve cardiac output in CHF patients do seem to improve exercise oscillatory ventilation and a similar mechanism could potentially influence periodic breathing too.
It is likely that multiple mechanisms mediating the interaction between PVCs and periodic breathing may be at play and this area would require continuing research. While the exact pathways of the interaction between PVCs and CSA are still being worked out, the clinical benefits of PVC treatment on CSA should be explored in larger studies. Our isolated case report showing a dramatic improvement in periodic breathing after successful PVC ablation is a provocative finding and in our knowledge, has not been described before.
Conclusion
The improvement of periodic breathing following successful ablation of PVCs is an intriguing finding. This suggests a possible causal relationship between the two. It will require more studies to confirm the association between sleep disordered breathing and PVCs. For now, it adds to another possible indication for ablation in patients with PVCs and CSA.
References
Gami AS
Pressman G
Caples SM
et al.
Association of atrial fibrillation and obstructive sleep apnea.
Prevalence and clinical characteristics of obstructive- and central-dominant sleep apnea in candidates of catheter ablation for atrial fibrillation in Japan.
Conflicts of Interest: The authors have no conflicts to disclose.
Key Teaching Points
There exists a well-established relationship between sleep disordered breathing and arrhythmias. The mechanisms of this interaction are not clear.
The improvement in atrial fibrillation burden following treatment of sleep apnea is well described. Early data suggests improvement in sleep apnea after atrial fibrillation ablation.
There appears to be an association between sleep disordered breathing and PVCs which is not well described in the literature.
We describe an unexpected finding of dramatic immediate improvement in periodic breathing after successful PVC ablation.
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