Feasibility of carbon dioxide insufflation and impact on epicardial approach utilization for ventricular tachycardia ablation in a midvolume referral center

BACKGROUND

Epicardial access is often crucial for successful ventricular tachycardia (VT) ablation, but it is often burdened by significant procedural risk. Intentional coronary vein exit and intrapericardial CO2 insufflation (EpiCO2) can facilitate subxiphoid pericardial access.

OBJECTIVE

This prospective study aimed to assess procedural feasibility, safety, and impact of the introduction of intrapericardial CO2 insufflation for epicardial access in a referral center for VT ablation.

METHODS

All consecutive patients treated with epicardial VT ablation between November 2022 and January 2024 with the EpiCO2 technique at Pisa University Hospital were prospectively enrolled and compared in terms of feasibility, efficiency, and safety with a local retrospective cohort of patients treated with subxiphoid dry puncture between July 2018 and October 2022.

RESULTS

Twenty-two consecutive patients (90.9% male; mean age, 54.3 years) underwent VT ablation with EpiCO2 during the study period. Epicardial access was achieved in all patients; median time from coronary sinus (CS) cannulation to epicardial access was 33 minutes. Intentional vein exit was successful in all cases, whereas CO2 insufflation was not feasible in 1 patient. There were no major complications and no significant bleeding. Since EpiCO2 introduction, epicardial approach utilization increased from 17.8% to 40% of all VT procedures. Comparison with 20 standard dry approach epicardial ablations showed no significant differences in terms of total procedural duration (322.5 [interquartile range, 296.75-363.75] minutes vs 359 [interquartile range, 323-409] minutes; P = .08).

CONCLUSION

In our single-center experience, EpiCO2 was feasible and safe and led to significant increase in procedural volume without affecting total procedural time compared with standard dry puncture.

Myocardial tissue characterization by segmental T2 mapping in thalassaemia major: detecting inflammation beyond iron

AIMS

We measured myocardial T2 values by a segmental approach in thalassaemia major (TM) patients, comparing such values against T2* values for the detection of myocardial iron overload (MIO), evaluating their potential in detecting subclinical inflammation, and correlating with clinical status.

METHODS AND RESULTS

One-hundred and sixty-six patients (102 females, 38.29 ± 11.49years) enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network underwent magnetic resonance imaging for the assessment of hepatic, pancreatic, and cardiac iron overload (T2* technique), of biventricular function (cine images), and of replacement myocardial fibrosis [late gadolinium enhancement (LGE)]. T2 and T2* values were quantified in all 16 myocardial segments, and the global value was the mean of all segments. Global heart T2 values were significantly higher in TM than in a cohort of 80 healthy subjects. T2 and T2* values were significantly correlated. Out of the 25 patients with a decreased global heart T2* value, 11 (44.0%) had reduced T2 values. No patient with a normal T2* value had a decreased T2 value.Eleven (6.6%) patients had a decreased global heart T2 value, 74 (44.6%) a normal global heart T2 value, and 81 (48.8%) an increased global heart T2 value. Biventricular function was comparable amongst the three groups, whilst LGE was significantly more frequent in patients with reduced vs. increased global heart T2 value. Compared with the other two groups, patients with reduced T2 values had significantly higher hepatic and pancreatic iron deposition.

CONCLUSION

In TM, T2 mapping does not offer any advantage in terms of sensitivity for MIO assessment but detects subclinical myocardial inflammation.

Never too old for something new: feasibility and long-term outcomes of leadless pacemaker implant in the elderly

Funding Acknowledgements

Type of funding sources: None.

Elderly patients may be at great risk of complications and present a higher incidence of comorbidities which make challenging PM implant procedure. The use of leadless pacing systems has imposed itself to overcome peri- and post-procedural complications related to the presence of transvenous leads and the post-operative recovery, being a favorable option in elderly patients.

The study aimed to investigate feasibility and long-term outcomes of M-TPS implant in a specific patient population, like the elderly, which represent a challenge for conventional cardiac pacing.

Methods

Between May 2014 and November 2021, 155 patients (120 males, mean age 78±9 y) underwent M-TPS implantation in our Center, targeting a non-apical site of delivery when feasible. A subgroup of 69 patients (52 males, 75.36%) were older than 80 years. All patients fulfilled standard criteria for PM implantation with specific indication to receive VVI pacing. Study population was divided into two groups according to age (group 1 < 79 years vs group 2≥80 years). The outcome evaluation included electrical performance (capture threshold, pacing impedance, R wave amplitude) before hospital discharge and then followed at 1, 6, and 12 months and then annually. Major complications were defined as life-threatening events, required surgical intervention or any event causing significant hemodynamic instability or resulting in death.

Results

In 69/155 cases (52 males, 75.36%) M-TPS was implanted in patients older than 80 years. There were no statistically significant differences between groups for demographics characteristics, except for age. The implant procedure was successful in all cases and no device-related events were registered during follow-up. In particular, no device infection and/or malfunction were reported. Patients were followed-up for an average of 24 months (median 18 months). No differences were observed between groups in procedure duration, single device delivery (group 1 vs group 2: 62.79% vs 65.22%, p=0.75), fluoroscopy time (group 1 vs group 2: 11.46 ±6.12 vs 11.37 ± 8.37 minutes, p=0.23), electrical performance at implant (group 1 vs group 2: pacing threshold 0.56 ± 0.37 V/0.24 ms vs 0.58 ± 0.31 V/0.24 ms, p=0.55; impedance 737.86 ± 173.50 Ohm vs 759.56 ± 255.35 Ohm, p=0.87; R wave amplitude 10.5 ± 5.18 mV vs 9.19 ± 4.45 mV, p=0.14) and at 18 [VB2] month F-U (group 1 vs group 2: pacing threshold 0.64 ± 0.55 V/0.24 ms vs 0.51 ± 0.1 V/0.24 ms, p=0.85; impedance 535.34 ± 102.53 Ohm vs 577.34 ± 69 Ohm, p=0.40; R wave amplitude 12.56 ± 4.56 mV vs 12.00 ± 5.8 mV, p=0.77[VB3] ).

Conclusions

The demand for cardiac pacing is strongly related to ageing, driving the clinical practice to look for the best solution for a considered fragile patient population. MTP-S implant is an effective and safe procedure in elderly patients, with similar electrical performance and outcome compared with younger patients at long-term follow.

Leadless pacemaker implant in the elderly: a safe and feasible solution

 

The use of leadless pacing systems could overcome peri-and post-procedural complications related to the presence of transvenous leads and the post-operative recovery, being a favorable option in elderly patients.

The study aimed to investigate feasibility and outcomes of M-TPS implant in a specific patient population, like the elderly, which represent a challenge for conventional cardiac pacing.

Methods

Between May 2014 and March 2021, 138 patients (106 males, 77%, mean age 78) underwent M-TPS implantation in our Centre, targeting a non-apical site of delivery when feasible. A subgroup of 59 patients (43 males, 73%) were older than 80 years. All patients fulfilled standard criteria for pacemaker implantation with specific indication to receive VVI pacing. Study population was divided into two groups according to age (group 1 <80 years vs group 2 ≥80 years). The outcome evaluation included electrical performance (capture threshold, pacing impedance, R wave amplitude) before hospital discharge and then followed at 1, 6, and 12 months and then annually. Major complications were defined as life-threatening events, requiring surgical intervention or any event causing significant hemodynamic instability or resulting in death. High pacing threshold (HPT) was defined as >1.0 V@ 0.24 ms.

Results

In 59/138 cases (43 males, 73%) M-TPS was implanted in patients older than 80 years. There were no statistically significant differences between groups for demographics characteristics, except for age, and PM implant indications. The implant procedure was successful in all cases and no device-related events were registered during follow-up. In particular, no device infection and/or malfunction were reported. Patients were followed-up for an average of 22,19±20,66 months (median 18 months). No differences were observed between groups in procedure duration (44,97±20,24 min vs 45,80±23,27 min; P=0,83), single device delivery (group 1 vs group 2: 63,16% vs 66,07%; P=0,73), fluoroscopy time (11,64±6,22 min vs 12,13±8,67 min; P=0,72) electrical performance at implant [group 1 vs group 2: pacing threshold 0,56±0,37 vs 0,58±0,32, P=0,78; impedance 727,53±170,36 vs 752,88±256,21, P=0,49; R wave amplitude 10,39±4,86 vs 9,26±4,66, P=0,18] and at median follow-up [group 1 vs group 2: pacing threshold 0,63±0,55 vs 0,51±0,1, P=0,40; impedance 535,34±102,53 vs 577,34±69,02, P=0,20; R wave amplitude 12,56±4,56 vs 12,00±5,80, P=0,77]

Conclusions

The demand for cardiac pacing is strongly related to ageing, driving the clinical practice to look for the best solution for a considered fragile population. MTP-S implant is an effective and safe procedure in elderly patients, with similar electrical performance and outcome compared with younger patients at mid-term follow-up.

Funding Acknowledgement

Type of funding sources: None.

Myocardial iron overload by cardiovascular magnetic resonance native segmental T1 mapping: a sensitive approach that correlates with cardiac complications

BACKGROUND

We compared cardiovascular magnetic resonance segmental native T1 against T2* values for the detection of myocardial iron overload (MIO) in thalassaemia major and we evaluated the clinical correlates of native T1 measurements.

METHODS

We considered 146 patients (87 females, 38.7 ± 11.1 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassaemia Network. T1 and T2* values were obtained in the 16 left ventricular (LV) segments. LV function parameters were quantified by cine images. Post-contrast late gadolinium enhancement (LGE) and T1 images were acquired.

RESULTS

64.1% of segments had normal T2* and T1 values while 10.1% had pathologic T2* and T1 values. In 526 (23.0%) segments, there was a pathologic T1 and a normal T2* value while 65 (2.8%) segments had a pathologic T2* value but a normal T1 and an extracellular volume (ECV) ≥ 25% was detected in 16 of 19 segments where ECV was quantified. Global native T1 was independent from gender or LV function but decreased with increasing age. Patients with replacement myocardial fibrosis had significantly lower native global T1. Patients with cardiac complications had significantly lower native global T1.

CONCLUSIONS

The combined use of both segmental native T1 and T2* values could improve the sensitivity for detecting MIO. Native T1 is associated with cardiac complications in thalassaemia major.

Arterial wall shear rate response to reactive hyperaemia is markedly different between young and older humans

KEY POINTS

The vasodilatory response to reactive hyperaemia is impaired with advancing age, but it is unclear whether this is because of an altered wall shear rate (WSR) stimulus or an altered flow-mediated dilatation (FMD) response. Using new technology that allows detailed WSR measurement, we assessed the WSR-FMD response in healthy older people. Our data show that older people have a markedly altered and diminished WSR response to reactive hyperaemia compared to young people, but reduced WSR alone does not fully explain reduced FMD. In young people, WSR appears to be coupled to FMD but, by age ∼65 years, the arterial vasodilatory response has begun to uncouple from the WSR stimulus. These findings point to the importance and utility of comprehensively characterizing the WSR-FMD response when using reactive hyperaemia to assess vascular function, as well as giving new insight into the age-related alteration in vascular function.

ABSTRACT

The vasodilatory response to reactive hyperaemia is impaired with age, but it is unknown whether this is because of an altered wall shear rate (WSR) stimulus or an altered flow-mediated dilatation (FMD) response to the WSR stimulus. Inherent difficulties in measuring blood flow velocity close to the arterial wall have prevented detailed assessment of the WSR-FMD response. Using an enhanced multigate spectral Doppler ultrasound system (ultrasound advanced open platform), we aimed to produce new data on the WSR-FMD relationship in healthy older adults. Sixty healthy people, comprising 28 young (27.5 ± 5.5 years) and 32 older (64.9 ± 3.7 years) individuals, underwent FMD assessment. Raw data were post-processed using custom-designed software to obtain WSR and diameter parameters. The data revealed that older people have a much altered and diminished WSR response to reactive hyperaemia compared to younger people [e.g. WSR peak: 622 (571-673) vs. 443 (396-491) 1/s in young and older respectively; P < 0.05]. However, reduced WSR alone does not appear to fully explain the reduced FMD response in older people because associations between WSR and FMD were few and weak. This was in contrast to young adults, where associations were strong. We conclude that WSR during FMD is much altered and diminished in older people, and there appears to be an 'uncoupling' of WSR from FMD in older people that may reflect a loss of precision in the reactive hyperaemia stimulus-response relationship. These findings also point to the importance and utility of comprehensively characterizing the WSR-FMD response when using reactive hyperaemia to assess vascular function.

Brachial artery vasodilatory response and wall shear rate determined by multigate Doppler in a healthy young cohort

Wall shear rate (WSR) is an important stimulus for the brachial artery flow-mediated dilation (FMD) response. However, WSR estimation near the arterial wall by conventional Doppler is inherently difficult. To overcome this limitation, we utilized multigate Doppler to accurately determine the WSR stimulus near the vessel wall simultaneously with the FMD response using an integrated FMD system [Ultrasound Advanced Open Platform (ULA-OP)]. Using the system, we aimed to perform a detailed analysis of WSR-FMD response and establish novel WSR parameters in a healthy young population. Data from 33 young healthy individuals (27.5 ± 4.9 yr, 19 females) were analyzed. FMD was assessed with reactive hyperemia using ULA-OP. All acquired raw data were postprocessed using custom-designed software to obtain WSR and diameter parameters. The acquired velocity data revealed that nonparabolic flow profiles within the cardiac cycle and under different flow states, with heterogeneity between participants. We also identified seven WSR magnitude and four WSR time-course parameters. Among them, WSR area under the curve until its return to baseline was the strongest predictor of the absolute ( R² = 0.25) and percent ( R² = 0.31) diameter changes in response to reactive hyperemia. For the first time, we identified mono- and biphasic WSR stimulus patterns within our cohort that produced different magnitudes of FMD response [absolute diameter change: 0.24 ± 0.10 mm (monophasic) vs. 0.17 ± 0.09 mm (biphasic), P < 0.05]. We concluded that accurate and detailed measurement of the WSR stimulus is important to comprehensively understand the FMD response and that this advance in current FMD technology could be important to better understand vascular physiology and pathology. NEW & NOTEWORTHY An estimation of wall shear rate (WSR) near the arterial wall by conventional Doppler ultrasound is inherently difficult. Using a recently developed integrated flow-mediated dilation ultrasound system, we were able to accurately estimate WSR near the wall and identified a number of novel WSR variables that may prove to be useful in the measurement of endothelial function, an important biomarker of vascular physiology and disease.

Carotid-Femoral Pulse Wave Velocity Assessed by Ultrasound: A Study with Echotracking Technology

Described here is a new method for determination of carotid-femoral pulse wave velocity (PWV) based on arterial diameter waveform recording by an ultrasound system. The study was carried out on 120 consecutive patients. Carotid-femoral PWV was determined using a tonometric technique (PWVpp, PulsePen, DiaTecne, Milan, Italy) and an echotracking ultrasound system (PWVet, E-Track, Aloka, Tokyo, Japan). The relationship between PWVpp and PWVet was evaluated by linear regression and Bland-Altman analysis. There was excellent agreement between PWVet and PWVpp (Pearson's r = 0.94, 95% confidence interval: 0.91-0.96, p < 0.0001; PWVet = 0.88 × PWVpp + 0.57). The Bland-Altman plot revealed an offset of -0.33 m/s with limits of agreement from -2.21 to 1.54 m/s. The coefficients of variation for within-subject repeatability between PWVet and PWVpp had were 5.79% and 8.47%, respectively, without significant differences in the Bland-Altman analysis. The results suggest that echotracking technology can provide a reliable estimate of aortic stiffness comparable to that of the tonometric techniques.