J.M. Morgan

Comparison of Coronary Venous Defibrillation with Conventional Transvenous Internal Defibrillation in Man

AbstractObjective: Animal studies have shown that defibrillation in coronary veins is more effective than in the right ventricle. We aimed to assess the feasibility of placing defibrillation electrodes in the middle cardiac vein (MCV) in man and its impact on defibrillation requirements. Methods: A prospective randomised study conducted in a tertiary referral centre. 10 patients (9 male) undergoing ICD implantation (65 (12) yrs) for NASPE/BPEG indications were studied. Defibrillation thresholds (DFT) were measured, using a binary search and an external defibrillator after 10 seconds of ventricular fibrillation, for the following configurations in each patient (order of testing randomised): RV + MCV → Can and RV → SVC + Can. Interventions: A dual coil defibrillation electrode was placed transvenously in the right ventricle (RV) in the conventional manner. Using a guiding catheter a 3.2 Fr (67.5 mm length) electrode was placed transvenously in MCV. A test-can was placed subcutaneously in the left pectoral region. Results: Lead placement was possible in 8/10 pts. Time to perform a middle cardiac venogram and place the electrode was 21 (23) mins. No adverse events were observed. Defibrillation current was less (6.7 (2.7) A) with RV + MCV → Can compared to the conventional RV → SVC + Can configuration (8.9 (3.4) A, p = 0.03). There was no significant difference in defibrillation voltage or energy. However, shock impedance was higher in the former configuration (57 (10) v. 43 (6) Ω, p = 0.001). Conclusions: In the majority of cases placement of a defibrillation lead in MCV is feasible. Defibrillation current requirements are 25% less when the shock is delivered using a MCV electrode.

Radiation Peak Skin Dose to Risk Stratify Electrophysiological Procedures for Deterministic Skin Damage

Ionising radiation is has the potential to cause harm both by increasing the probability future malignancy (stochastic mechanisms) and by direct physical injury (deterministic mechanisms). Several measures have been developed to quantify radiation exposure during a procedure and cardiologists usually refer to fluoroscopic screening time (FST). FST, however, has limitations for predicting deterministic injury which is directly dependant on peak skin dose (PSD). We compared FST to PSD for a range of interventional cardiac electrophysiology procedures. Methods: All patients undergoing electrophysiology procedures during a 2-month period in our institution were studied. Demographic details, nature of procedure, FST and PSD were measured. The FST to PSD ratio was calculated and compared between patient and procedural factors. Results: 67 procedures on patients (23 female) with body mass index (BMI) of 28 (SD 5)Kg/m2 were studied. Screening times ranged from 0.2 to 96.6 min (median 11.2). PSD ranged from <0.1 to 1108 mGy (median 141). There was a positive correlation between PSD to FST ratio and BMI (r= 0.59, p < 0.001). The PSD to FST ratio was higher in cardiac resynchronization therapy (CRT) devices than single or dual chamber ICDs (p= 0.002). Conclusion: FST is not a reliable predictor of deterministic skin injury and in high-risk procedures such as CRT devices and those on individuals of high BMI PSD should be measured.

Does the interval between a pre-shock and primary biphasic shock effect defibrillation thresholds?

15th World Congress in Cardiac Electrophysiology and Cardiac Techniques: Cardiostim 2006, Nice–French Riviera, France, 14-17 June 2006. In Europace, 2006, v. 8 Supplement 1, p. 43/5

Defibrillator and cardiac resynchronization therapy after mustard surgery for trans position of the great arteries

15th World Congress in Cardiac Electrophysiology and Cardiac Techniques: Cardiostim 2006, Nice–French Riviera, France, 14-17 June 2006. In Europace, 2006, v. 8 Supplement 1, p. 43/5

Value of pre-discharge defbrillator testing

15th World Congress in Cardiac Electrophysiology and Cardiac Techniques: Cardiostim 2006, Nice–French Riviera, France, 14-17 June 2006. In Europace, 2006, v. 8 Supplement 1, p. 43/5