BackgroundAtrial fibrillation (AF) is associated with myocardial infarction, and patients with AF and no obstructive coronary artery disease can present with symptoms and evidence of cardiac ischemia. We hypothesized that microvascular coronary dysfunction underlies these observations.Methods and ResultsMyocardial blood flow (MBF) at baseline and during adenosine stress and left ventricular and left atrial function were evaluated by magnetic resonance in 49 patients with AF (25 paroxysmal, 24 persistent) with no history of epicardial coronary artery disease or diabetes mellitus, before and 6 to 9 months after ablation. Findings were compared with those obtained in matched controls in sinus rhythm (n=25). Before ablation, patients with AF had impaired left atrial function and left ventricular ejection fraction and strain indices (all P<0.05 versus controls). MBF was impaired in patients both under baseline conditions (1.21±0.24 mL/min per g·[mm Hg·bpm/104]−1 versus 1.34±0.28 mL/min per g·[mm Hg·bpm/104]−1 in controls, P=0.044) and during adenosine stress (2.29±0.48 mL/min per g versus 2.73±0.37 mL/min per g in controls, P<0.001). Under baseline conditions, MBF correlated with left ventricular strain and left atrial function (all P≤0.001), so that cardiac function was most impaired in patients with the lowest MBF. Baseline and stress MBF remained unchanged postablation (both P=ns), and baseline MBF showed similar correlations with functional indices to those present preablation (all P≤0.001).ConclusionsBaseline and stress MBF are significantly impaired in patients with AF but no epicardial coronary artery disease. Reduction in MBF is proportional to severity of left ventricular and left atrial dysfunction, even after successful ablation. Coronary microvascular dysfunction may be a relevant pathophysiological mechanism in patients with a history of AF.
Introduction
Permanent His bundle pacing (PHBP) preserves physiological ventricular activation but technical difficulties have limited its widespread use. We report the first experience of PHBP performed with a new specific delivery sheath (Selectra 3D, Biotronik, Berlin, Germany) and an extendable‐retractable active screw, stylet‐driven pacing lead (Solia S 60, Biotronik).
Methods and Results
Clinical, procedural, ECG, and electrical data from consecutive patients undergoing PHBP with this system were collected at implantation, and follow‐up was performed after 1 month. Our cohort included 17 patients (71% males; mean age 76 ± 8 years) undergoing permanent pacing for sick sinus syndrome (59%) or atrioventricular block (41%). PHBP was successful in 15 (88%) procedures with mean procedure and fluoroscopy times of 63 ± 14 and 13 ± 5 min, respectively. The pacing threshold was 2.1 ± 1.1 V @1 ms and the sensed R‐wave amplitude was 5.6 ± 3.5 mV; bipolar and unipolar pacing impedances were 526 ± 115 and 369 ± 109 Ω, respectively. At discharge, neither procedure‐related complications nor lead dislodgement or pacing capture failures was reported. After 1 month, 14 (93%) patients still demonstrated His bundle stimulation and one (7%) lost His bundle capture but the lead revision was not necessary because the myocardial pacing threshold was stable. Follow‐up threshold (2 ± 1.1 vs. 2.3 ± 1.2 V@1 ms, p = .239) and sensed R‐wave amplitude (5.6 ± 3.4 vs. 6.4 ± 2.5, p = .403) was unchanged compared to the acute phase.
Conclusion
PHBP performed with a standard active fixation pacing lead and a new delivery sheath for His pacing is feasible, safe and demonstrates clinically acceptable electric performance both at implantation and after 1 month.
Background
Although radiofrequency (RF) catheter ablation of cavo‐tricuspid isthmus (CTI) is an established treatment for typical right atrial flutter (RAFL), it remains to be established whether local tissue impedance (LI) is able to predict effective CTI ablation and what LI drop values during ablation should be used to judge a lesion as effective. We aimed to investigate the ability of LI to predict ablation efficacy in patients with RAFL.
Methods
RF delivery was guided by the DirectSense™ algorithm. Successful single RF application was defined according to a defragmentation of atrial potentials (DAP), reduction of voltage (RedV) by at least 80% or changes on unipolar electrogram (UPC). The ablation endpoint was the creation of bidirectional conduction block (BDB) across the isthmus.
Results
392 point‐by‐point RF applications were analyzed in 48 consecutive RAFL patients. The mean baseline LI was 105.4 ± 12Ω prior to ablation and 92.0 ± 11Ω after ablation (p < 0.0001). According to validation criteria, absolute drops in impedance were larger at successful ablation sites than at ineffective ablation sites (DAP: 17.8 ± 6Ω vs. 8.7 ± 4Ω; RedV: 17.2 ± 6Ω vs. 7.8 ± 5Ω; UPC: 19.6 ± 6Ω vs. 10.1 ± 5Ω, all p < 0.0001). LI drop values significantly increased according to the number of criteria satisfied (ranging from 7.5Ω to 19.9). BDB was obtained in all cases. No procedure‐related adverse events were reported.
Conclusions
A LI‐guided approach to CTI ablation was safe and effective in treating RAFL. The magnitude of LI drop was associated with effective lesion formation and BDB and could be used as a marker of ablation efficacy.
Clinical trial registration
Catheter Ablation of Arrhythmias with a High‐Density Mapping System in Real‐World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.
Metformin is a frequently used anti-diabetic drug. In addition to the well-known modulating properties on glyco-metabolic control, metformin reduces cardiovascular (CV) risk partly independently of its anti-hyperglycaemic effect. The use of ‘new’ anti-diabetic drugs, inhibitors of the renal Na-glucose co-transporter (SGLTs-I or ‘gliflozines’) and GLP-1 receptor agonists (GLP1-RAs), has further contributed to challenge the strictly ‘gluco-centric’ view of diabetic CV disease. Several controlled trials have demonstrated that the cardio-renal benefits of gliflozines and GLP1-RAs are present regardless of the presence of metformin as ‘background’ therapy. The impact on the ‘cardio-renal continuum’ exerted by SGLTs-I was also noted in non-diabetic patients with heart failure and reduced or preserved ventricular function and different levels of renal function. These drugs reduced re-hospitalization, CV mortality, and progression to end-stage renal disease. These clinical acquisitions, implemented by Scientific Societies, have led to a change in the therapeutic approach to diabetic cardio-renal disease. Although metformin still represents a valid therapeutic option to be offered particularly to ‘naïve’ diabetic patients without previous cardio-renal events, SGLTs-I and/or GLP1-RAs emerge as ‘first-line’ drugs in diabetic patients with previous CV events, or at high CV risk, without having to request ‘on board’ metformin therapy.
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