Unipolar and bipolar electrogram characteristics of recurrent cases of idiopathic ventricular arrhythmias undergoing
Anupam Jena1, Mohammad Iqbal2, Yong-Soo Baek2
1Kalinga Institute of Medical Sciences, Republic of Korea.
Insights
Combining unipolar and bipolar electrograms (EGMs) improves ventricular tachycardia (VT) ablation by pinpointing earliest activation sites. This approach significantly reduces VT recurrence compared to using bipolar EGMs alone.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Catheter ablation (CA) for ventricular arrhythmias (VAs) can be limited when relying solely on bipolar electrograms (EGMs).
- Accurate identification of the VA origin is crucial for successful ablation and preventing recurrence.
Purpose of the Study:
- To evaluate if combined bipolar and unipolar EGMs enhance activation mapping for VA ablation.
- To determine if this combined approach reduces the recurrence rate of VAs after CA.
Main Methods:
- Analysis of electrogram data from patients undergoing repeat ablations for idiopathic out-flow tract VAs.
- Comparison of earliest local activation time (LAT), discrete potentials, polarity reversal, unipolar morphology, amplitude, and activation slope between first and second ablations.
Main Results:
- Local activation time was significantly earlier in repeat ablations (31.85 msec vs 36.90 msec).
- Recurrence rate was significantly lower (5.7%) with routine use of combined unipolar and bipolar EGMs compared to bipolar EGM alone (16.7%).
Conclusions:
- Combined bipolar and unipolar EGMs improve the delineation of earliest activation sites for effective VA ablation.
- The use of unipolar EGMs alongside bipolar EGMs is associated with a lower long-term recurrence rate of VAs.
Introduction:
Activation mapping guided catheter ablation (CA) of ventricular arrhythmias (VAs) is limited in some cases when it is only relied on bipolar electrogram (EGM). We hypothesized that activation mapping with use of combined bipolar and unipolar EGM facilitates to identify the focal origin of VAs and results in reduction of recurrence rate of CA of VAs.
Methods:
We analyzed the data of patients undergoing repeat ablations for idiopathic out-flow tract VAs. The EGM of the 1 st and 2 nd ablations were compared for earliest local activation time (LAT), presence of discrete potentials, and polarity reversal, unipolar potential morphology (QS or non-QS), potential amplitude and activation slope.
Results:
Thirty-seven patients were included. The Local activation time was significantly earlier in the 2nd ablation as compared to the 1st procedure (36.90 msec vs 31.85 msec, P < 0.01). The incidence of discrete potentials and polarity reversal were similar in both procedures (51% vs 57%, P = 0.8 and 62% in both the occasions, respectively). The unipolar voltage was similar in both occasions (6.94 mV vs 7.22 mV in repeat ablations, P = 0.7). The recurrence rate (5.7%) was significantly lower with routine use of combined unipolar and bipolar EGMs, as compared to the use of bipolar EGM alone (16.7%) CONCLUSIONS: Use of both bipolar and unipolar electrograms helps in better delineation of the sites of earliest activation for effective ablation of VAs. Use of unipolar electrograms in addition to bipolar electrograms is associated with lower long term recurrence rate.
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