Laura Plebani

Implantable Cardioverter Defibrillators and Cellular Telephones: Is There Any Interference?

The aim of our study was to consider cellular telephone interference using different cellular telephones and implantable cardioverter defibrillator (ICD) models. Thirty (26 men, 4 women) patients with ICDs were considered during follow‐up. The ICD models were: Telectronics (7), CPI (7), Medtronic (7), Ventritex (5), and Ela Medical (4). All patients were monitored with surface ECG; permanent telemetric endo‐ECG monitoring was activated. Then, the effect of two different European telephone systems were tested: TACS system (Sony CM‐R111, 2 W power) and GSM system (Motorola MG1–4A11, 2 W power). For both systems, the effect during call, reception, active conversation (dialogue), and passive conversation (listening) were observed. Cellular telephones were located first in contact with the programming head, then near the leads system, and lastly, in the hands of the patient. At the end of the evaluations, memories were interrogated again to check for false arrhythmia detections. In five of these patients during arrhythmia induction at device implant (first implant or ICD replacement), we also evaluated possible interference between cellular telephones in the reception phase and the ventricular fibrillation detection phase of the ICD. All evaluated models showed significant noise in the telemetric transmission when the cellular telephone (both TACS and GSM) was located near the ICD and the programming head; noise was particularly significant during call and reception, in most cases leading to loss of telemetry. No false arrhythmia detections have been observed during tests with cellular telephones located on the ICDs. During tests performed with cellular telephones located near the leads or in the hands of patients, no telemetric noises or false arrhythmia detections were observed. During induced ventricular fibrillation and cellular telephones in reception mode near the device, the arrhythmia recognition was always correct and not delayed. In conclusion, present ICD models seem to be well protected from electromagnetic interference caused by European cellular telephones (TACS and GSM), without under‐/oversensing of ventricular arrhythmias. However, cellular telephones disturb telemetry when located near the programming head. ICD patients should not be advised against the use of cellular telephones, but it has to be avoided during ICD interrogation and programming.

Reducing operator radiation exposure during cardiac resynchronization therapy

AIMS To quantify the reduction in equivalent dose at operators hand that can be achieved by placement of a radiation-absorbing drape (RADPAD) during long-lasting cardiac resynchronization therapy (CRT) procedures. METHODS AND RESULTS This is a prospective observational study that included 22 consecutive patients with drug-refractory heart failure who underwent implantation of a CRT device. The cases were randomly assigned to Group A (11 cases), performed without RADPAD, and to Group B (11 cases), performed using RADPAD. Dose equivalent at the examiners hand was measured as H(p)(0.07) and as a time-adjusted H(p)(0.07) rate (mGy/min) with a direct reading dosimeter. The mean fluoroscopy time was 20.8 ± 7.7 min and the mean dose area product (DAP) was 118.6 ± 45.3 Gy cm(2). No significant differences were found between body mass index, fluoroscopy time, and DAP between patients examined with or without RADPAD. The correlation between the fluoroscopy time and the DAP was high (R(2) = 0.94, P < 0.001). Mean dose and dose rate measurement without the RADPAD at the finger and hand were H(p)(0.07) = 1.27 ± 0.47 mGy per procedure and H(p)(0.07) rate = 0.057 ± 0.011 mGy/min, respectively. The dosage was reduced with the RADPAD to H(p)(0.07) = 0.48 ± 0.20 (P < 0.05) and to H(p)(0.07) rate = 0.026 ± 0.008 (P < 0.001), respectively. CONCLUSION A mean reduction of 54% in the equivalent dose rate to the operators hand can be achieved with the use of RADPAD. The use of the RADPAD in CRT devices implantation will make unlikely the necessity of limiting the yearly number of implants for high volume operators.

Long-term follow-up of DDDR closed-loop cardiac pacing for the prevention of recurrent vasovagal syncope.

Aims Vasovagal syncope (VVS) is a common disorder characterized by a drop in blood pressure accompanied with bradycardia; although it is generally considered a benign condition, some patients may be highly symptomatic despite general counselling and/or pharmacological therapy. Closed-loop stimulation (CLS), responding to myocardial contraction dynamics, demonstrated effectiveness in short-term prevention of recurrent VVS. The aim of this study was to evaluate CLS pacing in a long-term follow-up. Methods The study involved 35 patients (mean age 59 ± 15 years) with 3 years’ follow-up (mean 61 ± 35 months). We compared syncopal events and presyncopes before and after CLS implantation. Mean number of syncopes for patients was six (range 1–24; 212 syncopal spells registered) before pacemaker implantation. Results At follow-up, 29 of 35 patients (83%) were asymptomatic; one patient experienced recurrent loss of consciousness but reported an improvement in the quality of life (one syncope or presyncope per month after CLS, vs. one syncope per week and daily presyncopes before CLS). Five patients experienced syncopal recurrences after CLS (range: 1–7, with a total of 15 episodes); in all the cases, the number of post-CLS syncopes was significantly lower. Conclusion Our study seems to confirm previous results of short-term trials: DDDR-CLS pacing is an extremely useful tool in the prevention of recurring VVS, even in long-term follow-up.

Persistence of ICD indication at the time of replacement in patients with initial implant for primary prevention indication: Effect on subsequent ICD therapies

Background Indication to implantable cardioverter defibrillator (ICD) for primary prevention of sudden death relies on left ventricular ejection fraction (LVEF). We measured the proportion of patients in whom indication to ICD persisted at the time of generator replacement (GR) and searched for predictors of appropriate therapies after GR. Methods We identified all consecutive patients who had received an ICD at our hospital, for LVEF ≤35% and no previous arrhythmias or unexplained syncope. Then, we included the 166 patients who outlived their first device and underwent GR. Results At the time of GR (mean follow-up 59 ± 20 months), ICD indication (i.e. LVEF ≤35% or previously treated ventricular arrhythmias) persisted in 114 (69%) patients. After GR, appropriate ICD therapies were delivered in 30 (26%) patients with persistent ICD indication and in 12 (23%) of the remaining patients (p = 0.656). Nonetheless, the annual rate of therapies was higher in the first group (1.08 versus 0.53 events/year; p < 0.001), as well as the rate of inappropriate therapies (0.03 versus 0 events/year; p = 0.031). The only independent predictor of appropriate ICD therapies after GR was the rate of shocks received before replacement (Hazard Ratio: 1.41; 95% confidence interval: 1.01–1.96; p = 0.041). Conclusion In heart failure with reduced LVEF, ICD indication persisted at the time of GR in 69% of patients. However, even in the absence of persistent ICD indication at GR, the risk of recurrence of arrhythmic events was not null.

Non Invasive Cardiac Output Evaluation with CO2 Rebreathing Method for CRT Patients

Background : Cardiac resynchronization therapy with ICD (CRT-D) or pacemaker (CRT-P) is useful to reverse the deleterious effects of ventricular dyssynchronia in heart failure (HF) patients. To determinate the responders patients, hemodynamic parameters are difficult to evaluate during follow-up, due to the invasivity of the procedures. We compare hemodynamic response to CRT with cardiac output, not invasively detected (CO2 rebreathing method, Innocor system), with conventional clinical, functional and echocardiographic parameters. Methods : We enrolled 29 patients affected by end-stage dilated cardiomyopathy treated with CRT-P/CRT-D according to the latest guidelines (NYHA class II-IV, left ventricular ejection fraction [LVEF] ≤ 35%, QRS ≥ 120 ms, sinus rhythm, optimal medical therapy). Patients were evaluated before and after CRT (3 months), considering: NYHA class, Quality of Life score (Minnesota Living with Heart Failure questionnaire), QRS width, echocardiographic parameters (diastolic and systolic left ventricular volumes and related LVEF), six minutes walking test (6MWT) and cardiac output (detected with Innocor system). Results : Our data showed a significant improvement in Innocor cardiac output 3 months after CRT implant compared to baseline (4.01±0.72 vs 4.48±0.59 l/min, p=0.001). The percentage improvement in cardiac output correlates with the percentage increase in LVEF (25±6% vs 30±7%; r=0.541). The correlation is not statistically significant with NYHA class (from 2.52±0.73 to 1.78±0.60; r=0.098), QoL (from 22.57±15.37 to 9.91±9.14 score; r=0.231) and exercise tolerance (from 390±50 to 437±54 meters; r=0.144). Conclusions : The Innocor system is a promising non-invasive method to assess the cardiac output at baseline and during follow up in HF patients treated with CRT.