Electroanatomical Voltage Mapping to Distinguish Right-Sided Cardiac Sarcoidosis From Arrhythmogenic Right Ventricular Cardiomyopathy.

OBJECTIVES: This study sought to investigate the value of electroanatomical voltage mapping (EAVM) to distinguish cardiac sarcoidosis (CS) from arrhythmogenic right ventricular cardiomyopathy (ARVC) in patients with ventricular tachycardia from the right ventricle (RV). BACKGROUND: CS can mimic ARVC. Because scar in ARVC is predominantly subepicardial, this study hypothesized that the relative sizes of endocardial low bipolar voltage (BV) to low unipolar voltage (UV) areas may distinguish CS from ARVC. METHODS: Patients with CS affecting the RV (n = 14), patients with gene-positive ARVC (n = 13), and a reference group of patients without structural heart disease (n = 9) who underwent RV endocardial EAVM were included. RV region-specific BV and UV cutoffs were derived from control subjects. In CS and ARVC, segmental involvement was determined and low-voltage areas were measured, using <1.5 mV for BV and <3.9 mV, <4.4 mV, and <5.5 mV for UV. The ratio between low BV and low UV area was calculated generating 3 parameters: Ratio3.9, Ratio4.4 and Ratio5.5, respectively. RESULTS: In control subjects, BV and UV varied significantly among RV regions. The basal septum was involved in 71% of CS patients and in none of ARVC patients. Ratio5.5 discriminated CS from ARVC the best. An algorithm including Ratio5.5 ≥0.45 and basal septal involvement identified CS with 93% sensitivity and 85% specificity. This was validated in a separate population (CS [n = 6], ARVC [n = 10]) with 100% sensitivity and 100% specificity. CONCLUSIONS: EAVM provides detailed information about scar characteristics and scar distribution in the RV. An algorithm combining Ratio5.5 (area BV <1.5 mV/area UV <5.5 mV) and bipolar basal septal involvement allows accurate diagnosis of (isolated) CS in patients presenting with monomorphic ventricular tachycardia from the RV.

Detection of high-frequency artifact as a function of pulse generator algorithms and outer-insulation material.

BACKGROUND: A high rate of malfunction, predominantly intermittent high-frequency artifacts (HFAs), has been recently reported in Abbott Medical Tendril pacing leads. OBJECTIVE: To investigate the factors associated with the occurrence of HFAs on Tendril leads using a commonly used comparator lead for a control. METHODS: We reviewed institutional data for Medtronic CapSureFix 5076 and Abbott Medical Tendril pace-sense leads retrospectively. Recordings deemed to be due to electromagnetic interference and far-field oversensing were not included in the classification of HFAs. RESULTS: A total of 7673 leads were analyzed: 1628 Optim-insulated Tendril leads, 825 non-Optim Tendril leads, and 5220 CapSureFix 5076. HFAs were seen in 212 leads and were more frequently observed in Tendril compared to CapSureFix leads during a mean follow-up of 4.1 ± 3.6 years. Lower age at implant, defibrillator systems, atrial position, and connection to an Abbott Medical generator were associated with increased HFA. In multivariable analysis, only connection to Abbott Medical generators (odds ratio 7.686, P < .001) and age (odds ratio 0.988 per year, P = .016) were independently associated with HFAs on pace-sense leads. In an Abbott-generator-only analysis, Optim-insulated Tendril leads were more likely to display HFAs than non-Optim Tendril leads but not Medtronic CapSureFix 5076 leads. CONCLUSION: Abbott Medical pulse generators independently predict HFA in Tendril and CapSureFix 5076 leads, likely the result of displaying short or low-amplitude noise episodes that other devices do not record. When restricted to Abbott generators only, Optim-insulated Tendril leads show an increased incidence of HFAs when compared to non-Optim Tendril leads but not CapSureFix 5076 leads.

Change in QRS morphology as a marker of spontaneous elimination in verapamil-sensitive idiopathic left ventricular tachycardia.

BACKGROUND: Verapamil-sensitive idiopathic left ventricular tachycardia (verapamil-ILVT) is thought to be due to a reentry within the LV fascicular system. Radiofrequency catheter ablation (RFCA) is effective for elimination of the VT; however, a long-term prognosis of patients with verapamil-ILVT is still unclear. METHODS AND RESULTS: Eighty consecutive verapamil-ILVT patients (62 men, 31 ± 12 years of age, LVEF: 65 ± 4%) were enrolled. Seventy-six (95%) cases of VT involved right bundle branch block and left axis deviation. We retrospectively analyzed changes in the QRS duration (ΔQRS-d) and QRS axis (ΔQRS-axis) during follow-up and compared them with recurrence of VT. During a mean follow-up period of 10 years (2-32 years), no sudden death or heart failure occurred. Fifty-one (64%) patients underwent RFCA, and 46 (90%) of them had no VT without any medication after RFCA. The ΔQRS-d (16 ± 2 vs. 8 ± 1 ms, P = 0.24) and ΔQRS-axis (20 ± 4 vs. 4 ± 3 degrees, P = 0.23) were not different in patients with no VT (VT[-]) and those with recurrence of VT (VT[+]). However, in the remaining 29 patients without RFCA, VT was spontaneously eliminated in 16 patients. The ΔQRS-d (30 ± 6 vs. 6 ± 1 ms, P = 0.002) and ΔQRS-axis (23 ± 4 vs. 5 ± 2 degrees, P = 0.001) were significantly larger in VT(-) patients compared to VT(+) patients during follow-up. CONCLUSIONS: Some verapamil-ILVT patients who show QRS morphology changes over the follow-up period may become free from VT without any invasive or pharmacological treatments, suggesting that further altered LV fascicular conduction might eliminate the reentry of verapamil-ILVT.

Significance of electrocardiogram recording in high intercostal spaces in patients with early repolarization syndrome.

AIMS: Published reports regarding inferolateral early repolarization (ER) syndrome (ERS) before 2013 possibly included patients with Brugada-pattern electrocardiogram (BrP-ECG) recorded only in the high intercostal spaces (HICS). We investigated the significance of HICS ECG recording in ERS patients. METHODS AND RESULTS: Fifty-six patients showing inferolateral ER in the standard ECG and spontaneous ventricular fibrillation (VF) not linked to structural heart disease underwent drug provocation tests by sodium channel blockade with right precordial ECG (V1-V3) recording in the 2nd-4th intercostal spaces. The prevalence and long-term outcome of ERS patients with and without BrP-ECG in HICS were investigated. After 18 patients showing type 1 BrP-ECG in the standard ECG were excluded, 38 patients (34 males, mean age; 40.4 ± 13.6 years) were classified into four groups [group A (n = 6;16%):patients with ER and type 1 BrP-ECG only in HICS, group B (n = 5;13%):ERS with non-type 1 BrP-ECG only in HICS, group C (n = 8;21%):ERS with non-type 1 BrP-ECG in the standard ECG, and group D (n = 19;50%):ERS only, spontaneously or after drug provocation test]. During follow-up of 110.0 ± 55.4 months, the rate of VF recurrence including electrical storm was significantly higher in groups A (4/6:67%), B (4/5:80%), and C (4/8:50%) compared with D (2/19:11%) (A, B, and C vs. D, P < 0.05). CONCLUSIONS: Approximately 30% of the patients with ERS who had been diagnosed with the previous criteria showed BrP-ECG only in HICS. Ventricular fibrillation mostly recurred in patients showing BrP-ECG in any precordial lead including HICS; these comprised 50% of the ERS cohort.

Larger low voltage zone in endocardial unipolar map compared with that in epicardial bipolar map indicates difficulty in eliminating ventricular tachycardia by catheter ablation.

Patients with ischemic and non-ischemic cardiomyopathy often have substrate for ventricular tachycardia (VT) in the endocardium (ENDO), epicardium (EPI), and/or intramural. Although it has been reported that the ENDO unipolar (UNI) voltage map is useful in detecting EPI substrate, its feasibility to detect intramural scarring and its usefulness in radiofrequency catheter ablation (RFCA) remain unclear. To assess the relationship between the left ventricle (LV) ENDO UNI voltage map and the LV EPI bipolar (BIP) voltage map, and to determine the usefulness of the ENDO UNI voltage map to guide RFCA for VT in patients with cardiomyopathy undergoing combined ENDO- and EPI RFCA. Eleven patients with VT undergoing detailed ENDO and EPI electroanatomical mapping of the LV were included (mean age 59 ± 11 years, 9 men). We assessed the value of the LV ENDO UNI voltage map in identifying EPI and/or intramural substrate in these 11 patients with non-ischemic or ischemic cardiomyopathy. The underlying heart disease was dilated cardiomyopathy in 4 patients, cardiac sarcoidosis in 3, hypertrophic cardiomyopathy in 2, and ischemic heart disease in 2 patients. The mean LV ejection fraction was 24 ± 7 %. The low voltage zone (LVZ) was defined as <1.5 mV for LV ENDO BIP electrograms (EGMs), <8.3 mV for LV ENDO UNI EGMs, and <1.0 mV for LV EPI BIP EGMs. The surface area of each LVZ was measured. We also measured the LVZ of the spatial overlap between ENDO UNI and EPI BIP voltage maps using the transparency mode on CARTO software. We performed RFCA at the ENDO and EPI based on activation and/or substrate maps, targeting the LVZ and/or abnormal EGMs. The LVZ was present in the LV ENDO BIP voltage map in 10 of 11 patients (42 ± 33 cm(2)), and in the LV ENDO UNI voltage map in 10 of 11 patients (72 ± 45 cm(2)). The LVZ was present in the EPI BIP voltage map in 9 of 11 patients (70 ± 61 cm(2)), and the LVZ in the ENDO UNI voltage map was also seen in all 9 patients. The location of the LVZ in the EPI BIP map matched that in 45 ± 28 % of ENDO UNI voltage maps. The LVZ in the ENDO UNI voltage map was larger than that in the EPI BIP voltage map in 6 of 11 patients, and RFCA failed in 5 of these 6 patients. In the remaining 5 patients with a smaller LVZ in the ENDO UNI voltage map compared with the EPI BIP voltage map or no LVZ both at ENDO UNI and EPI BIP voltage map, VT was successfully eliminated in 4 of 5 patients. The LV ENDO UNI voltage map is useful in detecting EPI substrate in patients with cardiomyopathy. A larger LVZ in the ENDO UNI voltage map compared to that in the EPI BIP voltage map may indicate the presence of intramural substrate, which leads to difficulty in eliminating VT, even with combined ENDO- and EPI RFCA.

Clinical impact of the number of extrastimuli in programmed electrical stimulation in patients with Brugada type 1 electrocardiogram.

BACKGROUND: Use of programmed electrical stimulation (PES) for risk stratification of Brugada syndrome (BrS) is controversial. OBJECTIVE: To elucidate the role of the number of extrastimuli during PES in patients with BrS. METHODS: Consecutive 108 patients with type 1 electrocardiogram (104 men, mean age 46 ± 12 years; 26 with ventricular fibrillation [VF], 40 with syncope, and 42 asymptomatic) underwent PES with a maximum of 3 extrastimuli from the right ventricular apex and the right ventricular outflow tract. Ventricular arrhythmia (VA) was defined as VF or nonsustained polymorphic ventricular tachycardia >15 beats. Patients with VA induced by a single extrastimulus or double extrastimuli were assigned to group SD (Single/Double), by triple extrastimuli to group T (Triple), and the remaining patients to group N. RESULTS: VA was induced in 81 patients (VF in 71 and polymorphic ventricular tachycardia in 10), in 4 by a single extrastimulus, in 41 by double extrastimuli, and in 36 by triple extrastimuli. During 79 ± 48 months of follow-up, 24 patients had VF events. Although the overall inducibility of VA was not associated with an increased risk of VF (log-rank P = .78), group SD had worse prognosis than did group T (P = .004). Kaplan-Meier analysis in patients without prior VF also showed that group SD had poorer outcome than did group T and group N (P = .001). Positive and negative predictive values of VA induction with up to 2 extrastimuli were, respectively, 36% and 87%, better than those with up to 3 (23% and 81%, respectively). CONCLUSIONS: The number of extrastimuli that induced VA served as a prognostic indicator for patients with Brugada type 1 electrocardiogram. Single extrastimulus or double extrastimuli were adequate for PES of patients with BrS.