基于3S技术的制图法在控制和消除疟疾中的应用

疟疾发病具有空间异质性,通过绘制疟疾地图明确防治目标是疟疾防治和研究的重要方法.近年来迅速发展的3S技术不仅可以方便、准确地反映疫情时空特征,而且通过建立发病与相关流行病学资料的数学关系,为疟疾制图提供了新的研究手段.该文对制图法及其在疟疾控制和消除中的应用进行综述.     

Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping

OBJECTIVES:

Few studies have evaluated cardiac electrical activation dynamics after cardiac resynchronization therapy. Although this procedure reduces morbidity and mortality in heart failure patients, many approaches attempting to identify the responders have shown that 30% of patients do not attain clinical or functional improvement. This study sought to quantify and characterize the effect of resynchronization therapy on the ventricular electrical activation of patients using body surface potential mapping, a noninvasive tool.

METHODS:

This retrospective study included 91 resynchronization patients with a mean age of 61 years, left ventricle ejection fraction of 28%, mean QRS duration of 182 ms, and functional class III/IV (78%/22%); the patients underwent 87-lead body surface mapping with the resynchronization device on and off. Thirty-six patients were excluded. Body surface isochronal maps produced 87 maximal/mean global ventricular activation times with three regions identified. The regional activation times for right and left ventricles and their inter-regional right-to-left ventricle gradients were calculated from these results and analyzed. The Mann-Whitney U-test and Kruskall-Wallis test were used for comparisons, with the level of significance set at p≤0.05.

RESULTS:

During intrinsic rhythms, regional ventricular activation times were significantly different (54.5 ms vs. 95.9 ms in the right and left ventricle regions, respectively). Regarding cardiac resynchronization, the maximal global value was significantly reduced (138 ms to 131 ms), and a downward variation of 19.4% in regional-left and an upward variation of 44.8% in regional-right ventricular activation times resulted in a significantly reduced inter-regional gradient (43.8 ms to 17 ms).

CONCLUSIONS:

Body surface potential mapping in resynchronization patients yielded electrical ventricular activation times for two cardiac regions with significantly decreased global and regional-left values but significantly increased regional-right values, thus showing an attenuated inter-regional gradient after the cardiac resynchronization therapy.     

3D Non-Fluoroscopic Cryoablation of Right-Sided Accessory Pathways in Children: Monocentric Study and Literature Review

Background: Cryoablation of accessory pathways (APs) is effective and very safe in children, as previously reported by our group. The aim of this retrospective study was to evaluate the current efficacy of 3D non-fluoroscopic cryoablation of right sided APs in children, comparing results obtained with the Ensite Velocity^TM and the more recent Ensite Precision^TM 3D mapping systems. Methods and Results: From January 2016 to December 2019, 102 pediatric patients [mean age 12.5 ± 2.8, 62 males (61% of total cohort)] with right APs underwent 3D non-fluoroscopic transcatheter cryoablation at our Institution. Fifteen (14.7%) patients had previously undergone catheter ablation. Acute procedural success rate was 95.1% (n = 97). No significant differences were detected in acute success rates achieved with Ensite Velocity^TM or Ensite PrecisionTM systems nor between manifest (94%) and concealed APs (100%). No permanent complications occurred. During follow-up (428 ± 286 days, median 396 days [interquartile range 179-713]), 19 patients (19.6%) had recurrences. Recurrences were more frequent for parahissian/anterior APs compared to midseptal/posterior and lateral APs (p = 0.043). Recurrences were not related to the Ensite system used. A redo ablation procedure was attempted in 13 cases, 11 cryoablation and 2 radiofrequency ablations: the former was successful in 10 cases out of 11 (90.9%). Conclusion: 3D cryoablation of right-sided APs is associated with a very high acute success rate with limited use of fluoroscopy, resulting in great benefit to the children. Recurrence rates are not high and patients can be retreated with cryo-energy with higher success rates.     

High-density activation mapping of fractionated electrograms in the atria of patients with paroxysmal atrial fibrillation

BACKGROUND: Areas of complex fractionated atrial electrograms (CFAEs) have been implicated in the atrial substrate of atrial fibrillation (AF). The mechanisms underlying CFAE in humans are not well investigated. OBJECTIVES: The purpose of this study was to investigate the regional activation pattern associated with CFAE using a high-density contact mapping catheter. METHODS: Twenty patients with paroxysmal AF were mapped using a high-density multielectrode catheter. CFAE were mapped at 10 different sites (left atrium [LA]: inferior, posterior, roof, septum, anterior, lateral; right atrium [RA]: anterior, lateral, posterior, septum). Local atrial fibrillation cycle length (AFCL) was measured immediately before and after the occurrence of CFAE, and the longest electrogram duration (CFAEmax) was assessed. RESULTS: Longer electrogram durations were recorded in the LA compared with the RA (CFAEmax 118 +/- 21 ms vs 104 +/- 23 ms, P = .001). AFCL significantly shortened before the occurrence of CFAEmax compared with baseline (LA: 174 +/- 32 ms vs 186 +/- 32 ms, P = .0001; RA: 177 +/- 31 ms vs 188 +/- 31 ms, P = .0001) and returned to baseline afterwards. AFCL shortened by >or=10 ms in 91% of mapped sites. Two different local activation patterns were associated with occurrence of CFAEmax: a nearly simultaneous activation in all spines in 84% indicating passive activation, and a nonsimultaneous activation sequence suggesting local complex activation or reentry. CONCLUSION: Fractionated atrial electrograms during AF demonstrate dynamic changes that are dependent on regional AFCL. Shortening of AFCL precedes the development of CFAE; thus, cycle length is a major determinant of fractionation during AF. High-density mapping in AF may help to differentiate passive activation of CFAE from CFAE associated with an active component of the AF process.     

Radiofrequency ablation of left atrial flutter mediated with double potentials in a seemingly normally structured heart

Background

Left atrial flutter (left AFL) is common in patients who undergo atrial fibrillation ablation and cardiac surgery; however, few reports describe left AFL in detail in a seemingly normally structured heart, and the mechanisms of the occurrence of such arrhythmia are still not clear. We describe left AFL in patients without prior cardiac surgery or catheter ablation and discuss the electrophysiological characteristics that may explain the preferential generation and perpetuation of such tachycardia.

Methods and results

Eleven patients with left AFL, who had no history of cardiac surgery or interventions, underwent electrophysiological studies and 3-dimensional electroanatomic mapping studies. Echocardiography revealed a relatively mild dilation of the left atrium, mild to moderate mitral regurgitation, and a normal left ventricular ejection fraction. The electroanatomic mapping during tachycardia showed a “reentrant” activation pattern in all patients. The mean tachycardia cycle length was 266 ± 17 ms. A single-loop reentrant circuit was identified in 7 patients. A counterclockwise left atrial flutter evolved around the mitral valve annulus in 6 patients. The tachycardia rotated around the left atrial anterior wall in 1 patient. Four patients exhibited a double-loop reentrant circuit with a “figure of 8” pattern reentry. Double potentials as the critical isthmus of the circuit were identified in the left atrial anterior wall near the mitral annulus which displayed a low-voltage area matched with the left atrium–aorta contiguity. The conduction velocity was significantly slower in the double-potential recording area than in the lateral mitral annulus (0.36 ± 0.03 m/s vs 0.74 ± 0.12 m/s; P < 0.05). Successful ablation around the double-potential recording site caused an interruption of the tachycardia, and remained free of recurrence during a 12-month follow-up in all patients.

Conclusion

Left AFL in patients without a history of surgery or ablation is rarely observed in clinical practice. The successful site of ablation was within the anterior wall near the mitral annulus showing the double potentials as the critical part of the reentrant circuit. This suggests that perhaps a double potential-targeted ablation may be effective for these patients.     

Ablação epicárdica para prevenção da fibrilhação ventricular em doente com síndrome de Brugada

We present the case of a 60‐year‐old woman with Brugada syndrome, permanent type 1 electrocardiographic pattern, who had previously received an implantable cardioverter‐defibrillator. She suffered frequent syncopal episodes and multiple appropriate shocks (around five per month) due to polymorphic ventricular tachycardia/ventricular fibrillation, refractory to quinidine therapy. Combined epicardial and endocardial electroanatomical mapping was performed with a view to substrate ablation. An area of abnormal fractionated electrograms, lasting up to 370 ms and up to 216 ms after the end of the surface QRS, was identified in the epicardium in the lower anterior part of the right ventricular outflow tract. Extensive epicardial ablation of this area, which eliminated the fractionated electrograms, led to the disappearance of the Brugada electrocardiographic pattern six weeks after ablation. Despite discontinuation of quinidine, no further ventricular arrhythmias occurred during follow‐up, which is still of short duration.     

Le diagnostic de l’amylose cardiaque par résonance magnétique : les éléments discriminants

Infiltrative cardiomyopathies refers to deposits of substances in the myocardial tissue resulting in a structural abnormality and/or alteration of cardiac function. Cardiac amyloidosis is an extracellular infiltration of amyloid fibril. Cardiac magnetic resonance imaging (MRI) is essential (in the) for its diagnosis. MRI sequences (morphological, viability and parametric mapping) allow a structural and dynamic analysis of the cardiac function as well as a characterization of the myocardial tissue: edema, fatty infiltration, fibrosis. In cardiac amyloidosis, the morphological sequences classically highlight ventricular hypertrophy and thickening of the heart valves. Ventricular functions are assessed by the cine sequences (The cine sequences make it possible to evaluate the ventricular functions.) The viability sequences show (a more diffuse distribution of hypersignals) an abnormal pattern of late gadolinium enhancement in both circumferential and sub-endocardial distribution. The relaxometry sequences or parametric T1 and/or T2 mapping allow the spatial visualization of quantitative changes of the myocardium. The presence of macroscopic myocardial edema or fibrosis causes a prolongation of the native T1 and an increase of the extracellular volume.     

Spatiotemporal analysis,hotspot mapping,and clustering of confirmed cases of COVID-19 in the initial phase of the pandemic in Qom province,Iran

Objective: To identify the incidence rate, relative risk, hotspot regions and incidence trend of COVID-19 in Qom province, northwest part of Iran in the first s...