Characterization of human coronary sinus valves by direct visualization during biventricular pacemaker implantation.

BACKGROUND: The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus. OBJECTIVES: The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices. METHODS: The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC). RESULTS: The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization. CONCLUSIONS: Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.

The effect of gender on mortality or appropriate shock in patients with nonischemic cardiomyopathy who have implantable cardioverter-defibrillators.

BACKGROUND: As heart disease is increasingly recognized in women and as important studies have elucidated the benefit of implantable cardioverter defibrillators (ICDs) in patients with nonischemic cardiomyopathy (NICM), little is known regarding the effect of gender difference on arrhythmic risk in this population. We sought to determine if there are gender differences in arrhythmic risk and potential defibrillator benefit in patients with NICM. METHODS: The records of 767 consecutive patients who underwent ICD implant at the Stanford Medical Center from 1984 to 2002 were reviewed. Only patients with NICM were considered (n = 201, 26.2%). Of these, 140 patients had clinical follow-up information available. Baseline variables were examined, including age, baseline heart rate, ejection fraction, and medications. We evaluated the time to first shock as well as all-cause mortality in this patient population. Kaplan-Meier survival curves were plotted, a log-rank test was used to evaluate significance, and Cox-proportional hazards test was used for multivariate analysis. RESULTS: There were 88 (62.9%) men and 52 (37.1%) women. Between male and female patients, there were no significant differences in baseline mean age (54.8 +/- 1.9 years vs 53.1 +/- 2.3 years, respectively), ejection fraction (35.2 +/- 2.0% vs 33.3 +/- 2.3%, respectively), and mean left ventricular end-diastolic dimension (6.4 +/- 0.3 cm vs 5.9 +/- 0.2 cm, respectively). Mean follow-up time was 30.8 months. Thirty-two male patients (36.4 +/- 0.05%) received appropriate shocks compared with 20 female patients (38.5 +/- 0.07%). Mean time to the first appropriate shock was 11.9 +/- 3.9 months for male patients and 21.3 +/- 5.8 months for female patients (P = 0.2). Nineteen male patients (21.6 +/- 0.05%) died or received heart transplant during the follow-up period compared with 6 female patients (11.5 +/- 0.04%) (P = 0.11). CONCLUSION: Male and female patients with NICM who received ICDs had similar rate of appropriate shock and mortality. In this population gender does not appear to be an important risk factor for mortality or arrhythmic events.

Early human experience with use of a deflectable fiberoptic endocardial visualization catheter to facilitate coronary sinus cannulation.

BACKGROUND: Despite improvements in cardiac resynchronization therapy (CRT) implantation techniques, a significant minority of CRT attempts are unsuccessful. Inability to cannulate the coronary sinus (CS) because of difficult anatomy is a major reason for unsuccessful CRT implantation. Direct visualization of intracardiac structures during the implant may facilitate access into the CS. The present study describes CRT implantation with the aid of an endocardial visualization catheter (EVC). METHODS: Fifty-eight consecutive patients (mean age 72 +/- 12 years; ejection fraction 26.2% +/- 7.0%; New York Heart Association [NYHA] class 2.9) underwent CRT implantation using a steerable fiberoptic EVC (Acumen Medical, Inc., Sunnyvale, CA). RESULTS: The EVC was able to visualize the CS ostium in all cases. The CS was successfully cannulated in 57 (98.3%) of 58 patients. The time from vascular access to CS visualization was 6 +/- 5 minutes, and the total time to CS access was 8 +/- 6 minutes. Successful left ventricle (LV) lead implantation was accomplished in 55 (94.8%) of 58 patients. Three patients who had a previous history of failed LV lead implantation were successfully implanted using the EVC. CONCLUSION: Fiberoptic imaging of intracardiac structures during CRT implantation may be performed rapidly in a wide range of patients with an EVC. The ability to visualize right atrial anatomy may aid CS access and LV lead implantation.

Electrocardiographic arrhythmia risk testing.

Among the most compelling challenges facing cardiologists today is identification of which patients are at highest risk for sudden death. Automatic implantable cardioverter-defibrillators are now indicated in many of these patients, yet the role of noninvasive risk stratification in classifying patients at high risk is not well defined. The purpose of this review is to evaluate the various electrocardiographic (ECG) techniques that appear to have potential in assessment of risk for arrhythmia. The resting ECG (premature ventricular contractions, QRS duration, damage scores, QT dispersion, and ST segment and T wave abnormalities), T wave alternans, late potentials identified on signal-averaged ECGs, and heart rate variability are explored. Unequivocal evidence to support the widespread use of any single noninvasive technique is lacking; further research in this area is needed. It is likely that a combination of risk evaluation techniques will have the greatest predictive power in enabling identification of patients most likely to benefit from device therapy.