Relationship Between Catheter Forces, Lesion Characteristics, "Popping," and Char Formation: Experience with Robotic Navigation System

Introduction: Popping, char and perforation are complications that can occur following catheter ablation. We measured the amount of grams (g) applied to the endocardium during ablation using a sensor incorporated in the long sheath of a robotic system. We evaluated the relationship between lesion formation, pressure, and the development of complications.
Methods: Using a robotic navigation system, lesions were placed in the left atrium (LA) at six settings, using a constant duration (40 seconds) and flow rate of either 17 cc/min or 30 cc/min with an open irrigated catheter (OIC). Evidence of complications was noted and lesion location recorded for later analysis at necropsy.
Results: Lesions using 30 Watts (W) were more likely to be transmural at higher (>40 g) than lower (<30 g) pressures (75% vs 25%, P < 0.001). Significantly higher number of lesions using >40 g of pressure demonstrated "popping" and crater formation as compared with lesions with 20–30 g of pressure (41% vs 15%, P = 0.008). A majority of lesions placed using higher power (45 W) with higher pressures (>40 g) were associated with char and crater formation (66.7%). No lesions using 10 g of pressure were transmural, regardless of the power. Lesions placed with a power setting less than 35 W were more likely to result in "relative" sparing of the endocardial surface than lesions at a power setting higher than 35 W (62% vs 33.3%, P = 0.02) regardless of the pressure.
Conclusions: When using an OIC, lower power settings (≤35 W) and lower/medium contact pressure were more likely to show a "relative" spared endocardial surface. Overall, contact pressure between 20 g and 30 g and a power setting of 40 W appeared to achieve transmurality by preserving safety.     

Long‐Term Functional and Neurocognitive Recovery in Patients Who Had an Acute Cerebrovascular Event Secondary to Catheter Ablation for Atrial Fibrillation

PVAI and Stroke . Introduction: Cerebral thromboembolic event (CTE) is a possible complication of pulmonary vein antrum isolation (PVAI). The objective of this study was to report long‐term functional and neurocognitive recovery in patients who had a CTE during or within 48 hours of catheter ablation. Methods and Results: We screened 3,060 patients who underwent PVAI between January 2000 and June 2007. Out the 3,060 patients, 26 patients (0.8%) (61 ± 8 years, 88% males) had a CTE during or within 48 hours of the procedure. We followed these 26 patients (study group) over time and assessed their functional and neurocognitive recovery status. No preferential vascular territory for the site of obstruction was found; right anterior circulation‐5 patients (26%), left anterior circulation‐5 patients (26%), posterior circulation‐3 patients (16%), and 2 or more territories‐6 patients (32%), (P‐value = 0.8). The average international normalized ratio at the time of CTE was 1.33 ± 0.4. Two patients died during the study period. At the end of 38.4 ± 24 months follow‐up, most surviving patients had complete neurocognitive and functional recovery irrespective of the severity of periprocedural stroke. Conclusions: Periprocedural stroke in the setting of catheter ablation for atrial fibrillation is relatively rare. When it occurs, complete functional and neurocognitive recovery over time is the likely outcome for most patients. (J Cardiovasc Electrophysiol, Vol. 21, pp. 412–417, April 2010)     

Melanoacanthoma Simulating Pigmented Spitz Nevus: an Unusual Dermoscopy Pitfall

BACKGROUND: The starburst pattern is the dermoscopic hallmark of pigmented Spitz nevus, although it has been rarely observed in melanoma as well. OBJECTIVE: To describe a case of melanoacanthoma simulating pigmented Spitz nevus. MATERIAL AND METHODS: Clinical, dermoscopic, and histopathologic examinations were performed for the occurrence of a 4-mm pigmented skin lesion on the hip of a 38-year-old Caucasian woman. RESULTS: Dermoscopy examination of the lesion disclosed a stereotypical starburst pattern characterized by pigmented streaks symmetrically distributed at the periphery. A preoperative diagnosis of pigmented Spitz nevus was made, and the lesion was excised. However, subsequent histopathologic examination revealed a melanoacanthoma. CONCLUSION: The starburst pattern, although diagnostic for pigmented Spitz nevus, can be rarely observed in other benign or malignant pigmented skin lesions. Accordingly, all lesions in adults exhibiting a starburst pattern or other spitzoid features should be excised for histopathologic evaluation.     

Postnatal development of intestinal endocrine cell populations in the water buffalo

The frequency and distribution of 11 endocrine cell populations were studied in the intestine of differently aged buffalo, grouped on the basis of diet: 2-d-olds (suckling), 5-mo-olds (weaning) and 5-y-olds (ruminant adult diet). The endocrine cell populations were identified immunocytochemically using antisera against 5-hydroxytryptamine (5-HT), somatostatin, gastrin, cholecystokinin (CCK), COOH-terminal octapeptide of gastrin/CCK, neurotensin, motilin, gastric inhibitory polypeptide (GIP), secretin, glucagon/glicentin (GLU/GLI) and polypeptide YY (PYY). In adult buffalos the regional distribution of endocrine cells is similar to that of other adult ruminants. During postnatal development, these cell types showed the following changes in their frequency and distribution: (1) 5-HT, neurotensin and gastrin/CCK immunoreactive cells (i.c.) showed a decrease in frequency with age; (2) somatostatin i.c. frequency remained stable with age; (3) motilin, GIP, secretin and CCK i.c. showed a slight increase in frequency with age; (4) GLU/GLI and PYY i.c. decreased in frequency with age in the small intestine, caecum and proximal colon and an increase in frequency in the rectum. It was hypothesised that the endocrine cell types, whose presence and localisation is substantially stable in all examined ages, probably contain substances that are strictly necessary for intestinal function. In contrast the hormones contained in the cell populations that decreased with age, are probably involved in physiological needs during the milk and weaning diet or play a role in intestinal growth.     

Feasibility and Safety of Using an Esophageal Protective System to Eliminate Esophageal Thermal Injury: Implications on Atrial-Esophageal Fistula Following AF Ablation

Background: Ablation for atrial fibrillation (AF) requires energy delivery in close proximity to the esophagus (Eso) which has accounted for the LA-Eso fistula, a rare but life-threatening complication.
Purpose: We evaluated an Eso cooling system to protect the Eso during RF ablation.
Methods and Results: An " in vitro " heart-Eso preparation was initially used to test a temperature-controlled fluid-circulating system (EPSac [esophageal protective system]—RossHart Technologies Inc.) and an expandable compliant Eso sac during cardiac RF delivery (4 mm tip, perpendicular to the heart, 15 g pressure) at 25, 35, and 45 W, 100 ± 5 Ω for 30 seconds with the EPSac at 25, 15, 10, and 5°C. All cardiac lesions were transmural. Eso thermal injury could only be avoided with the EPSac at 10 and 5°C. The system was then tested in 6 closed chest dogs, each receiving 12 RFs (LA aiming at the Eso) for 30 seconds: without EPSac (control) at 35 W (1 dog); at 45 W with EPSac at 25°C (1 dog), 10°C (2 dogs), and 5°C (2 dogs). The EPSac volume was intentionally increased to displace the Eso toward the LA (2 dogs 5 and 10°C). Eso injured control and EPSac at 25°C; Eso spared EPSac at 5 and 10°C, without Eso displacement. Shallow external Eso injury noted when intentionally displacing the Eso toward the LA.
Conclusions: The EPSac spares the Eso from collateral thermal injury. It requires circulating fluid at 5 or 10°C and a compliant sac to avoid displacement of the Eso. Its safety and efficacy remain to be demonstrated in patients undergoing AF ablation.     

Improvement of Cardiac Function in Patients with Severe Congestive Heart Failure and Coronary Artery Disease by Dual Chamber Pacing with Shortened AV Delay

Medical therapy often fails to control symptoms of severe heart failure. The possibility of modifying to some degree the global ventricular performance with the implantation of a physiological dual chamber pacemaker, set with a short atrioventricular delay (100 msec), has been adopted in two patients with severe heart failure due to coronary artery disease. The baseline clinical condition of both patients was characterized by leg edema, ascites, dyspnea at rest, or even orthopnea with a functional New York Heart Association (NYHA) class III-IV. Acute measurements of hemodynamic and echocardiographic parameters during stepwise shortening of AV interval guided the pacemaker implantation and setting of AV delay in the chronic phase. Within a few days after pacemaker implantation, both patients considerably improved their clinical status as well as their functional NYHA class, improving to class U in one patient and to class II-III in the other patient. In addition, modification of systolic and diastoJic parameters paralleled these improvements functional class and clinical condition. Pacemaker therapy in severe heart failure refractory to medical therapy can be of considerable benefit in patients whose quality-of-life is severely compromised when pharmacological therapy is no longer effective. Acute hemodynamic and echocardiographic testing is useful in assessing the most appropriate AV delay and pacing mode.