Phrenic Nerve Block for Diaphragmatic Pain: Case Report.

Referred chronic shoulder pain may arise from diaphragmatic irritation. It can potentially be alleviated by blockade of the phrenic nerve. There is literature describing its use in acute pain conditions; yet for chronic pain, there are no reports. We present 2 cases of chronic diaphragmatic irritation causing ipsilateral referred shoulder pain. Patients experienced significant pain relief and a reduction in opioid consumption after receiving an ultrasound-guided phrenic nerve block. While the phrenic nerve block shows promise for pain relief, carefully evaluating its benefits and risks is recommended before considering its application in selected cases.

Value of high-output pace-mapping of the right phrenic nerve for enabling safe radiofrequency ablation of atrial fibrillation: insights from three-dimensional computed tomography segmentation.

AIMS: Right phrenic nerve (RPN) injury is a disabling but uncommon complication of atrial fibrillation (AF) radiofrequency ablation. Pace-mapping is widely used to infer RPN's course, for limiting the risk of palsy by avoiding ablation at capture sites. However, information is lacking regarding the distance between the endocardial sites of capture and the actual anatomic RPN location. We aimed at determining the distance between endocardial sites of capture and anatomic CT location of the RPN, depending on the capture threshold. METHODS AND RESULTS: In consecutive patients undergoing AF radiofrequency ablation, we defined the course of the RPN on the electroanatomical map with high-output pacing at up to 50 mA/2 ms, and assessed RPN capture threshold (RPN-t). The true anatomic course of the RPN was delineated and segmented using CT scan, then merged with the electroanatomical map. The distance between pacing sites and the RPN was assessed. In 45 patients, 1033 pacing sites were analysed. Distances from pacing sites to RPN ranged from 7.5 ± 3.0 mm (min 1) when RPN-t was ≤10 mA to 19.2 ± 6.5 mm (min 9.4) in cases of non-capture at 50 mA. A distance to the phrenic nerve > 10 mm was predicted by RPN-t with a ROC curve area of 0.846 [0.821-0.870] (P < 0.001), with Se = 80.8% and Sp = 77.5% if RPN-t > 20 mA, Se = 68.0% and Sp = 91.6% if RPN-t > 30 mA, and Se = 42.4% and Sp = 97.6% if non-capture at 50 mA. CONCLUSION: These data emphasize the utility of high-output pace-mapping of the RPN. Non-capture at 50 mA/2 ms demonstrated very high specificity for predicting a distance to the RPN > 10 mm, ensuring safe radiofrequency delivery.

Superior vena cava isolation using a pentaspline pulsed-field ablation catheter: feasibility and safety in patients undergoing atrial fibrillation catheter ablation.

AIMS: Superior vena cava (SVC) isolation during atrial fibrillation catheter ablation is limited by the risk of collateral damage to the sinus node and/or the phrenic nerve. Due to its tissue-specificity, we hypothesized the feasibility and safety of pulsed-field ablation (PFA)-based SVC isolation. METHODS AND RESULTS: One hundred and five consecutive patients undergoing PFA-based AF catheter ablation were prospectively included. After pulmonary vein isolation (±posterior wall isolation and electrical cardioversion), SVC isolation was performed using a standardized workflow. Acute SVC isolation was achieved in 105/105 (100%) patients after 6 ± 1 applications. Transient phrenic nerve stunning occurred in 67/105 (64%) patients but without phrenic nerve palsy at the end of the procedure and at hospital discharge. Transient high-degree sinus node dysfunction occurred in 5/105 (4.7%) patients, with no recurrence at the end of the procedure and until discharge. At the 3-month follow-up visit, no complication occurred. CONCLUSION: SVC isolation using a pentaspline PFA catheter is feasible and safe.

Initial clinical experience with the balloon-in-basket pulsed field ablation system: acute results of the VOLT CE mark feasibility study.

AIMS: Pulsed field ablation (PFA) for the treatment of atrial fibrillation (AF) potentially offers improved safety and procedural efficiencies compared with thermal ablation. Opportunities remain to improve effective circumferential lesion delivery, safety, and workflow of first-generation PFA systems. In this study, we aim to evaluate the initial clinical experience with a balloon-in-basket, 3D integrated PFA system with a purpose-built form factor for pulmonary vein (PV) isolation. METHODS AND RESULTS: The VOLT CE Mark Study is a pre-market, prospective, multi-centre, single-arm study to evaluate the safety and effectiveness of the Volt™ PFA system for the treatment of paroxysmal (PAF) or persistent AF (PersAF). Feasibility sub-study subjects underwent phrenic nerve evaluation, endoscopy, chest computed tomography, and cerebral magnetic resonance imaging. Study endpoints were the rate of primary serious adverse event within 7 days and acute procedural effectiveness. A total of 32 subjects (age 61.6 ± 9.6 years, 65.6% male, 84.4% PAF) were enrolled and treated in the feasibility sub-study and completed a 30-day follow-up. Acute effectiveness was achieved in 99.2% (127/128) of treated PVs (96.9% of subjects, 31/32) with 23.8 ± 4.2 PFA applications/subject. Procedure, fluoroscopy, LA dwell, and transpired ablation times were 124.6 ± 28.1, 19.8 ± 8.9, 53.0 ± 21.0, and 48.0 ± 19.9 min, respectively. Systematic assessments of initial safety revealed no phrenic nerve injury, pulmonary vein stenosis, or oesophageal lesions causally related to the PFA system and three subjects with silent cerebral lesions (9.4%). There were no primary serious adverse events. CONCLUSION: The initial clinical use of the Volt PFA System demonstrates acute safety and effectiveness in the treatment of symptomatic, drug refractory AF.

PolarX vs Arctic Front for Cryoballoon Ablation of Paroxysmal AF: The Randomized COMPARE CRYO Study.

BACKGROUND: Pulmonary vein isolation is an effective treatment for atrial fibrillation (AF). Cryoballoon ablation using the Arctic Front cryoballoon (Medtronic) was found to be superior to antiarrhythmic drug treatment. Recently, a novel cryoballoon system was introduced (PolarX, Boston Scientific). OBJECTIVES: The purpose of this study was to compare the efficacy and safety of the 2 cryoballoons in a randomized controlled trial. METHODS: Patients with symptomatic paroxysmal AF were enrolled in 2 centers and randomized 1:1 to pulmonary vein isolation using the PolarX or the Arctic Front cryoballoon. All patients received an implantable cardiac monitor. The primary endpoint was first recurrence of atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia [AT]) between days 91 and 365. Procedural safety was assessed by a composite of tamponade, phrenic nerve palsy lasting >24 hours, vascular complications, stroke/transient ischemic attack, atrioesophageal fistula or death up to 30 days. RESULTS: A total of 201 patients were enrolled. At 1 year, recurrence of atrial tachyarrhythmia had occurred in 41 of 99 patients (41.6%) assigned to the PolarX group and in 48 of 102 patients (47.1%) assigned to the Arctic Front group (HR: 0.85 [95% CI: 0.56-1.30]; P = 0.03 for noninferiority; P = 0.46 for superiority). The safety endpoint occurred in 5 patients (5%) in the PolarX group (n = 5 phrenic nerve palsies lasting >24 hours), whereas no safety endpoints occurred in the Arctic Front group (P = 0.03). CONCLUSIONS: In this randomized controlled trial using implantable cardiac monitors for continuous rhythm monitoring, the novel PolarX cryoballoon was noninferior compared with the Arctic Front cryoballoon regarding efficacy. However, the PolarX balloon resulted in significantly more phrenic nerve palsies. (Comparison of PolarX and the Arctic Front Cryoballoons for PVI in Patients With Symptomatic Paroxysmal AF [COMPARE-CRYO]; NCT04704986).

Incidence of phrenic nerve injury during pulmonary vein isolation using different cryoballoons: data from a large prospective ablation registry.

AIMS: Phrenic nerve injury (PNI) is the most common complication during cryoballoon ablation. Currently, two cryoballoon systems are available, yet the difference is unclear. We sought to compare the acute procedural efficacy and safety of the two cryoballoons. METHODS: This prospective observational study consisted of 2,555 consecutive atrial fibrillation (AF) patients undergoing pulmonary vein isolation (PVI) using either conventional (Arctic Front Advance) (AFA-CB) or novel cryoballoons (POLARx) (POLARx-CB) at 19 centers between January 2022 and October 2023. RESULTS: Among 2,555 patients (68.8 ± 10.9 years, 1,740 men, paroxysmal AF[PAF] 1,670 patients), PVIs were performed by the AFA-CB and POLARx-CB in 1,358 and 1,197 patients, respectively. Touch-up ablation was required in 299(11.7%) patients. The touch-up rate was significantly lower for POLARx-CB than AFA-CB (9.5% vs. 13.6%, p = 0.002), especially for right inferior PVs (RIPVs). The touch-up rate was significantly lower for PAF than non-PAF (8.8% vs. 17.2%, P < 0.001) and was similar between the two cryoballoons in non-PAF patients. Right PNI occurred in 64(2.5%) patients and 22(0.9%) were symptomatic. It occurred during the right superior PV (RSPV) ablation in 39(1.5%) patients. The incidence was significantly higher for POLARx-CB than AFA-CB (3.8% vs. 1.3%, P < 0.001) as was the incidence of symptomatic PNI (1.7% vs. 0.1%, P < 0.001). The difference was significant during RSPV (2.5% vs. 0.7%, P < 0.001) but not RIPV ablation. The PNI recovered more quickly for the AFA-CB than POLARx-CB. CONCLUSIONS: Our study demonstrated a significantly higher incidence of right PNI and lower touch-up rate for the POLARx-CB than AFA-CB in the real-world clinical practice.

Cuando la retirada de la ventilación mecánica es dificultosa en la UCIP: caso clínico / When the weaning from mechanical ventilation is difficult in the UCIP: report of a case

Paciente de 22 meses que presenta como complicación postquirúrgica, de cirugía torácica, sección del nervio frénico derecho con la consiguiente parálisis hemidiafragmática. Se comentan algunos aspectos fisiopatológicos de tal afección y se discuten las estrategias ante un weaning dificultoso

Relación entre arteria torácica interna y nervios frénico y frénicos accesorios / Relation between the internal thoracic artery and the phrenic and accessory phrenic nerves

La revascularización directa del miocardio, usando la arteria torácica interna puede provocar aproximadamente en el 10,0 por ciento de los pacientes parálisis hemidiafragmática como complicación clínica postoperatoria según Wilcox et al., 1990. Las injurias físicas del nervio frénico, pueden ser causadas por su proximidad con el corazón, por el desconocimiento de su distribución anatómica y de su relación con la arteria torácica interna según Abd et al., 1989. Esto nos movió a efectuar un estudio anatómico del nerivio frénico y frénicos accesorioa en 100 cadáveres de individuos brasileños, adultos de ambos sexos, con edades variables entre 20 y 84 años, procedentes del Servicio de Obitos de la Escola Paulista de Medicina, Sao Paulo, Brasil. El nervio frénico (NF) fue observado en el 100 por ciento de los casos. En el 81,0 por ciento encontramos el NF en ambos lados; en 9,0 por ciento el NF al lado derecho y el NF y un nervio frénico accesorio (NFa) en el lado izquierdo; en el 6,0 por ciento el NF y un NFa en el lado derecho y el NF en lado izquierdo; en 3,0 por ciento el NF y un NFa a ambos lados y en 1,0 por ciento el NF en el lado derecho y el NF y dos NFa en el lado izquierdo. En su relación con la arteria torácica interna, ambos nervios frénicos son anteriormente a la arteria (56,0 por ciento), el derecho es anterior y el izquierdo posterior (20,0 por ciento), el derecho es posterior y el izquierdo anterior (10,0 por ciento) y ambos frénicos son posteriores a la arteria (14,0 por ciento). La distancia entre el origen de la arteria torácica interna y el cruzamiento del nervio frénico, varió entre 0,3-4,5 cm con una media de 1,6 ñ 0.77 cm

Paresia diafragmática adquirida como complicación del drenaje de neumotórax por toracotomía cerrada / Diaphragmatic paresia acquired as complication of pneumothorax drainage by closed thoracotomy

La parálisis diafragmática traumática secundaria al drenaje pleural para la evacuación de un neumotórax hipertensivo es una rara complicación pero que debe ser tenida en cuenta ya que agrava la insuficiencia respiratoria del paciente, prolonga el tiempo de asistencia respiratoria e incrementa los riesgos relacionados a internaciones prolongadas. Es importante la comprobación de la ubicación del catéter en la radiografía post drenaje y la inmediata corrección de la misma en caso que ésta sea inadecuada. Si se comprueba paresia/parálisis diafragmática debe colocarse al paciente en Trendelenburg invertido. De persistir la parálisis la consulta quirúrgica determinará la oportunidad y beneficio de la plicatura.