Alhadi, Abdulmueti

Abstract Objective This report describes the first use of the Affera Sphere-9 dual-energy catheter for slow pathway modification in atrioventricular nodal re-entrant tachycardia (AVNRT) during atrial fibrillation (AF) ablation in a patient with a dual-chamber pacemaker, illustrating a streamlined single-catheter approach. Case presentation A 74-year-old man with prior cryoablation for AF, mitral valve repair, and a recently implanted dual-chamber pacemaker was referred for repeat AF ablation due to symptomatic, recurrent AF (30% burden). Left atrial mapping with the Sphere-9 catheter revealed reconnection at the right superior pulmonary vein, right carina, and across prior roof and floor lines. Using pulsed field (4-s lesions, 8 mm spacing) and supplemental radiofrequency (RF) energy, the left atrial posterior wall was re-isolated. Cavo-tricuspid isthmus ablation was performed with RF and pulsed field applications, achieving bidirectional block. During subsequent testing, typical AVNRT was induced. To maximize efficiency, slow pathway modification was performed with the same Sphere-9 catheter, using shortened RF applications (3 s), a lower target temperature (60°C), and an 80% current limit, at an inferior-posterior site 1.3–2.5 cm from the His signal. Junctional acceleration was observed without atrioventricular block, indicating successful slow pathway modification. The procedure was completed without fluoroscopy or complications, and follow-up device interrogation showed no recurrence of AF or AVNRT. Conclusion This case demonstrates the feasibility and acute safety of using a single dual-energy lattice-tip catheter for combined AF and AVNRT ablation, potentially reducing procedure time, catheter exchanges, and cost; larger studies are needed to assess long-term outcomes.

Key Points Genetic testing of individuals suspected of monogenic urinary stone disease resolved 34% of families with 22 different genes detected. Resolved individuals had a lower baseline and last visit eGFR and earlier age of stone presentation than the unresolved group. Specific phenotypes and younger diagnostic age were associated with a monogenic cause, allowing refinement of future screenings. Background Urinary stone disease with a clear genetic cause, monogenic stone disease (MSD), is increasingly recognized as a significant proportion of the total population. When MSD is suspected, genetic testing provides a firm diagnosis that can alter management and treatment. Here, we present testing results from a large cohort with suspected MSD. Methods Patients with features suggestive of MSD (early onset, family history, frequent stones, nephrocalcinosis [NC], and/or CKD) were recruited by the Rare Kidney Stone Consortium and genotyped for up to 160 known or candidate MSD genes via a targeted massively parallel sequencing panel. We compared clinical and biochemical features between genetically resolved MSD and unresolved individuals. Results Of 426 families (657 patients) enrolled, 145 (34%) were resolved with identified disease associated variants in 22 known MSD genes. Ninety-nine families were biallelic, 37 monoallelic, and two digenic. An additional 21 of the 231 screened family members were resolved. Genes identified in ten or more families include the following: AGXT , HOGA1 , SLC34A3 , CYP24A1 , SLC3A1 , and CLCN5 . Compared with the unresolved group, MSD probands had a lower baseline and last visit eGFR, earlier age of stone presentation, and more stone events and procedures/year of life. The resolve rate was higher in those <16 years, and NC was seen earlier in the MSD group. Overall, NC was a risk factor for lower eGFR. Among the specific disorders, patients with primary hyperoxaluria had the earliest age of stone and NC diagnosis, and as expected, the highest urinary oxalate level. Conclusions Our study emphasizes the value of selecting patients enriched for factors associated with MSD, and comprehensive genetic testing to achieve a high yield of genetic diagnoses. Significant clinical and biochemical characteristics of patients with MSD were defined. A definitive MSD diagnosis facilitates individualized management and strategies to delay disease progression in probands and affected family members.