Antonio Ciccaglioni

Efficacy of ivabradine administration in patients affected by inappropriate sinus tachycardia

BACKGROUND Inappropriate sinus tachycardia (IST) is characterized by an elevated heart rate (HR) at rest and an exaggerated HR response to physical activity or emotional stress. Beta-blockers and calcium channel blockers are the first-line therapy but sometimes are poorly tolerated due to side effects. OBJECTIVE The purpose of this study was to evaluate the efficacy and safety of ivabradine, a selective inhibitor of the I(f) current of the sinoatrial node, in patients affected by IST. METHODS Eighteen consecutive symptomatic patients (2 men and 16 women; mean age 45 +/- 15 years) affected by IST were enrolled in the study. Every patient underwent resting ECG, 24-hour Holter ECG, and exercise ECG at baseline and at 3-month and 6-month follow-up. RESULTS Sixteen patients (14 women; mean age 41 +/- 14 years) completed the study. Holter ECG assessment showed a significant reduction of medium HR (P <.001) and maximal HR (P <.001, basal vs 3-6 months; P = .02, 3 vs 6 months). Minimal HR slightly decreased at 3 months and then stabilized (P = .49, 3 vs 6 months) despite an increased drug dose. Stress test showed a significant decrease at rest (P <.001) and maximal HR (P <.05), suggesting an increased tolerance to physical stress, which was confirmed by a progressive increase of maximal load reached (>100 W) during stress test at 3 months (75%) and 6 months (85%). One patient was excluded because of phosphenes despite dose lowering, and another patient did not complete the protocol. CONCLUSION Ivabradine could represent an effective and safe alternative to calcium channel blockers and beta-blockers for treatment of IST.

Retrospective case-control analysis of patients with staphylococcal infections receiving daptomycin or glycopeptide therapy

Glycopeptides have been considered the antimicrobials of choice for serious meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-resistant coagulase-negative staphylococci (MR-CoNS) infections for several years. Daptomycin is a new option for the treatment of these infections, including those exhibiting reduced susceptibility to glycopeptides. The aim of this study was to compare glycopeptides and daptomycin for the treatment of infections caused by MRSA or MR-CoNS. Data for 106 patients with bloodstream infections (bacteraemia or infective endocarditis) or skin and soft-tissue infections (SSTIs) were retrospectively reviewed, of which 43 were treated with daptomycin (DAP group) and 63 were treated with vancomycin or teicoplanin (GLYCO group). Patients included in the two comparison groups were homogeneous in terms of age, risk factors and clinical severity. Aetiology was mainly represented by MRSA in both groups, followed by various species of MR-CoNS. Daptomycin was used more frequently in patients with central venous catheter-associated bacteraemia or pacemaker-associated infection. Patients with SSTIs included in the GLYCO group had a longer mean duration of antibiotic therapy (18.2 days vs. 14.6 days; P=0.009) and a longer mean length of hospital stay (28.2 days vs. 19.6 days; P=0.01) compared with those included in the DAP group. A longer mean duration of antibiotic therapy was also observed in patients with bloodstream infections receiving glycopeptide therapy (25.6 days vs. 18 days; P=0.004). In conclusion, the good clinical efficacy of daptomycin is associated with a more rapid resolution of the clinical syndrome and a reduced length of hospitalisation. This latter aspect may have important pharmacoeconomic implications, promoting the use of daptomycin in the clinical setting.

Sonication of Explanted Cardiac Implants Improves Microbial Detection in Cardiac Device Infections

ABSTRACT The sonication technique has been shown to be a promising tool for microbiological diagnosis of device-related infections. We evaluated the usefulness of the sonication method for pathogen detection in 80 explanted cardiac components collected from 40 patients, and the results were compared with those of conventional cultures. Forty subjects undergoing cardiac device removal were studied: 20 had cardiac device infection, and 20 subjects underwent elective generator replacement or revision in the absence of infection. Sonication of explanted devices was more sensitive than traditional culture for microbial detection (67% and 50%, respectively; P = 0.0005). The bacterial count detected in sonication fluid culture was significantly higher than that detected in traditional culture in both infected (P = 0.019) and uninfected (P = 0.029) devices. In the infected patients, sonication fluid culture yielded a significantly higher rate of pathogen detection in explanted electrodes than traditional culture (65% versus 45%; P = 0.02), while no differences were found in the generators. Ten strains were detected only through sonication fluid culture: 6 Staphylococcus epidermidis strains, 1 Staphylococcus hominis strain, 2 Corynebacterium striatum strains, and 1 Brevundimonas sp. Neither the type nor the duration of antimicrobial therapy before device removal had an effect on the diagnostic performance of sonication fluid culture (P = 0.75 and P = 0.56, respectively). In the patients without infection, sonication fluid culture was positive in 8 cases (40%), whereas conventional culture was positive in only 4 (20%). In summary, the sonication technique improves the microbiological diagnosis of explanted cardiac devices.

Curative Radiofrequency Catheter Ablation for Permanent Junctional Reciprocating Tachycardia

Two patients with the permanent form of junctional reciprocating tachycardia successfully treated with the radiofrequency catheter ablation technique are described. In both patients a reentrant tachycardia utilizing a conceoled slow conducting posterior septal accessory pathway for retrograde conduction was demonstrated. Radiofrequency current was delivered below the coronary sinus orifice. The procedure resulted in ablation of the accessory pathway conduction in both patients. During the follow‐up, both patients remained free from tachycardia on no medication. This report demonstrates that the arrhythmogenic substrate of the permanent junctional reciprocating tachycardio can be easily suppressed by means of the radiofrequency catheter technique.

Detection of biofilm-associated implant pathogens in cardiac device infections: High sensitivity of sonication fluid culture even in the presence of antimicrobials

Introduction: Sonication showed more sensitivity than traditional culture in the diagnosis of device infections. Aims of the study were to assess the role of sonication in the microbiological diagnosis and management of cardiac device infections (CDIs), to evaluate the sensitivity of sonication in patients on antimicrobial therapy at the time of device removal, and to analyze biofilm formation of the isolated strains. Materials and Methods: A total of 90 devices (31 generators and 59 electrodes) collected from 31 patients with infection underwent sonication before culture. Devices were sonicated for 5 min and centrifuged at 3200 rpm for 15 min. Intraoperative traditional cultures were performed in 26 patients. Microorganisms were identified using conventional methods. Staphylococcal strains were tested for slime production. Results: Microbiological diagnosis was achieved in 28 patients (90%). Sonicate fluid was positive in 68/90 (76%) of devices (27/31 [87%] generators and 41/59 [69%] electrodes), whereas intraoperative pocket swabs grew bacteria in 10/26 patients (38%, P= 0.0007). Among leads, 37/59 (62.7%) yielded bacteria even in the absence of vegetation. Coagulase-negative Staphylococci accounted for 83.8% (57/68) of the total; Staphylococcus aureus and Gram-negative bacilli were found in 4.4% (3/68) and 5.8% (4/68), respectively. Biofilm production was present in 15/22 (69%) staphylococcal strains. Overall, patients on therapy (n = 23) had a microbiological diagnosis in 20/23 (86.9%) and 7/22 (30.4%) through sonication and intraoperative cultures, respectively (P = 0.0002). Discussion: Our data showed the high sensitivity of sonication in the diagnosis of CDIs, even in patients under antimicrobial therapy. Conclusion: Sonication represents an essential tool for both diagnosis and management of CDIs.

Bidirectional Tachycardia after an Acute Intravenous Administration of Digitalis for a Suicidal Gesture

Acute digoxin intoxication is a life-threating condition associated with severe cardiotoxicity. Female gender, age, low lean body mass, hypertension, and renal insufficiency may worsen the prognosis. Arrhythmias caused by digitalis glycosides are characterized by an increased automaticity coupled with concomitant conduction delay. Bidirectional tachycardia is pathognomonic of digoxin intoxication, but it is rarely observed. An 83-year-old woman was admitted to the Emergency Department after self-administration of 5 mg of digoxin i.v. for suicidal purpose. Her digoxin serum concentration was 17.4 ng/mL. The patient developed a bidirectional tachycardia and the Poison Control Center of the hospital provided digoxin immune fab. Bidirectional tachycardia quickly reversed and the patient remained stable throughout the hospital stay. This case shows that a multiple disciplinary approach, involving cardiologists and toxicologists, is essential for the management of digoxin intoxication. The optimal treatment of this rare event depends on the clinical conditions and on the serum drug concentration of the patient. Digoxin immune fab represents a safe, effective, and specific method for rapidly reversing digitalis cardiotoxicity and should be started as soon as the diagnosis is defined.