Progression of aortic valve dysfunction in 51 adult patients with congenital bicuspid aortic valve: assessment and follow up by Doppler echocardiography.

OBJECTIVE: To assess the pattern and progression of aortic valve dysfunction by serial Doppler echocardiographic examinations in ambulatory adult patients with congenital bicuspid aortic valve. DESIGN AND SETTING: Retrospective analysis of patients referred for Doppler echocardiography over a four year period. SUBJECTS: Fifty one adult patients with echocardiographic diagnosis of congenital bicuspid aortic valve had serial Doppler echocardiographic studies at least six months apart. There were 40 men and 11 women with a mean age of 36 years. MAIN OUTCOME MEASURE: Doppler echocardiographic values of aortic valve dysfunction. Cardiac events including endocarditis and aortic valve replacement were also evaluated. RESULT: Coarctation was present in five patients. 31 (61%) patients had a functionally normal bicuspid aortic valve defined as a mean gradient < 25 mm Hg and mild regurgitation. Significant aortic regurgitation was present in 15 patients (moderate in 12 and severe in three). Three patients had isolated aortic stenosis and two patients had combined aortic valve dysfunction. At a median follow up of 21 months (range six to 46 months), six patients had aortic valve surgery (one for aortic stenosis, three for aortic regurgitation, and two for endocarditis). Only 22 patients (43%) continued to have a functionally normal aortic valve. CONCLUSION: In this cohort of fairly young patients, aortic regurgitation is more common than aortic stenosis. Progression of aortic valve dysfunction occurs in patients with pre-existing valve dysfunction and even in those with normal aortic valve function at the initial echocardiographic examination.

Conscious sedation with intermittent midazolam and fentanyl in electrophysiology procedures.

OBJECTIVES: To determine the safety and efficacy of intermittent midazolam and fentanyl conscious sedation for electrophysiology procedures (EP). BACKGROUND: Intermittent midazolam and fentanyl conscious sedation was administered in 700 consecutive cases (175 radiofrequency ablations, 163 EP studies, 261 pacemakers, and 101 implantable cardioverter-defibrillators) for 471 patients (239 males, 51%) mean age 65 +/- 15 years. The mean dose of midazolam was 0.063 mg/kg/hr and fentanyl was 0.591 microgram/kg/hr. METHODS: Cardiac rate and rhythm were monitored continuously, while blood pressure and arterial oxygen saturation were noninvasively assessed every 5 minutes. Drugs were administered in aliquots of 0.5 to 2.0 mg of midazolam and 6.25 to 25 micrograms of fentanyl as determined by clinical condition every 15 to 30 minutes. RESULTS: There were no deaths. In no case was endotracheal intubation required. Mild hypoxemia (SaO2 > 80%, but < 90%) occurred in 17 cases (2.4%) and was easily reversed with verbal stimulation and oropharyngeal repositioning (12 cases, 1.7%), increased F1O2 (3 cases, 0.4%), or intravenous naloxone (2 cases, 0.3%). Reversible hypotension (systolic blood pressure < 90, but > 60 mmHg) occurred in 14 patients (2.0%) and was corrected with intravenous crystalloid bolus or flumazenil (10 cases, 1.4%) or inotrope infusion (4 cases, 0.6%). No patient stay was prolonged due to sedation. Only five patients (0.7%) had any recollection of the procedure, while two (0.3%) were aware of pain. All hypoxemic episodes occurred during the first hour, whereas 43% (6/14) of hypotensive episodes occurred after the first hour. CONCLUSION: Conscious sedation with intermittent midazolam and fentanyl is safe and efficacious for a broad range of EP procedures.

High incidence of Pellethane 90A lead malfunction.

AIMS: The long-term performance of Pellethane 80A (P80A) endocardial pacing leads has previously been called into question. We report our experience with an endocardial pacemaker lead with silicone outer and Pellethane 2363-90A (P90) inner insulator. METHODS: Between November 1993 and March 1998, 129 P90A and 189 non-P90A ventricular leads were implanted. Lead malfunction was defined as > or = 25%) deviation in lead impedance or a two-fold reduction in sensing threshold during follow-up. Sensing and capture thresholds and lead impedance were assessed intraoperatively, immediately postoperatively, at 24 h and 6-12 weeks following implant and semiannually thereafter. Adequacy of lead positioning and lead-header interface were documented radiographically in each case. RESULTS: During 204 patient years of follow-up, 10/129 (8%) Oscor RX P90A leads malfunctioned. Average time to malfunction was 14 +/- 11 months. During 166 patient years of follow-up, none of the 189 non-P90A ventricular leads met criteria for malfunction (P < 0.05). There was no difference in patient age, sex, and arrhythmia indication between groups. Sensing problems were overcome with pacemaker reprogramming. CONCLUSION: We conclude that Oscor RX passive fixation ventricular leads with external silicone and inner P90A insulation exhibit an 8%, insulation malfunction rate within 14 +/- 11 months of implant. This is significantly higher than non-P90A leads implanted with identical technique and follow-up regimen. More frequent follow up may be warranted in patients with P90A containing leads.

Failure of defibrillator paddle as mimic for subcutaneous patch lead during nonthoracotomy implantable cardioverter defibrillator lead configuration assessment.

It is a common, although virtually unsubstantiated, practice to assess the efficacy of nonthoracotomy lead systems for implantable cardioverter defibrillators using a defibrillator paddle as mimic for the subcutaneous patch lead. We report a case in which an adequate defibrillation threshold was documented with the nonthoracotomy lead system using a defibrillator paddle but not following implantation of the true subcutaneous patch lead. This case suggests that the substitution of a defibrillator paddle for the subcutaneous patch lead during nonthoracotomy lead system evaluation may have significant limitations in assessing lead configuration efficacy.