Biomedical subjects

Frederick Ehlert

Publications and source records attributed to Frederick Ehlert.

4 recordsLinked to original sources

PubMed2006

Syncope, other risk factors, and the implantable defibrillator for sudden death prevention in hypertrophic cardiomyopathy.

Sudden cardiac death is the most devastating complication of hypertrophic cardiomyopathy. Since HCM may present at young age, and since the risk period for sudden arrhythmic death may be long, decision-making in HCM patients may be difficult, and have lifelong implications. Community based studies show a sudden death mortality of approximately 1%/year. Certain patients can be identified by their clinical characteristics, and through testing, to have higher annual risk, as high as 4-5%/year. Risk factors sudden cardiac death include: family history of HCM and sudden death, recurrent syncope, ventricular tachycardia, as detected by Holter monitoring or exercise testing, subnormal (<20 mmHg) increase in systolic blood pressure on maximal exercise testing and lastly marked (especially >30 mm) left ventricular hypertrophy. The implantable defibrillator has been shown to avert sudden death in selected HCM patients deemed to be at high risk.

Cardiomyopathy, Hypertrophic↗

PubMed2004

Increased incidence of life-threatening ventricular arrhythmias in implantable defibrillator patients after the World Trade Center attack.

OBJECTIVES: This study was designed to evaluate whether the destruction of the World Trade Center (WTC) on September 11, 2001 (9/11), led to an increased frequency of ventricular arrhythmias among patients fitted with an implantable cardioverter-defibrillator (ICD). BACKGROUND: The WTC attack induced psychological distress. Because ICDs store all serious arrhythmias for months, the attack provided a unique opportunity to compare pre- and post-9/11 frequencies of potentially lethal arrhythmias among ICD patients. METHODS: Two hundred consecutive ICD patients who presented for regularly scheduled follow-up to six affiliated clinics were recruited into this observational study. The electrograms stored in the ICDs for the three months before 9/11 and 13 months thereafter were scrutinized in a blinded manner (relative to date) for all ventricular tachyarrhythmias (tachycardia or fibrillation) triggering ICD therapy. RESULTS: The frequency of tachyarrhythmias increased significantly for the 30 days post-9/11 (p = 0.004) relative to all other months between May 2001 and October 2002. In the 30 days post-9/11, 16 patients (8%) demonstrated tachyarrhythmias, compared with only seven (3.5%) in the preceding 30 days, representing a 2.3-fold increase in risk (95% confidence interval 1.1 to 4.9; p = 0.03). The first arrhythmic event did not occur for three days following 9/11, with events accumulating in a progressive non-clustered pattern. CONCLUSIONS: Ventricular arrhythmias increased by more than twofold among ICD patients following the WTC attack. The delay in onset and the non-clustered pattern of these events differ sharply from effects following other disasters, suggesting that subacute stress may have served to promote this arrhythmogenesis.

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PubMed2003

Robotically assisted left ventricular epicardial lead implantation for biventricular pacing.

OBJECTIVES: Ventricular resynchronization might be achieved in a minimally invasive fashion using a robotically assisted, direct left ventricular (LV) epicardial approach. BACKGROUND: Approximately 10% of patients undergoing biventricular pacemaker insertion have a failure of coronary sinus (CS) cannulation. Rescue therapy for these patients currently is limited to standard open surgical techniques. METHODS: Ten patients with congestive heart failure (New York Heart Association class 3.4 +/- 0.5) and a widened QRS complex (184 +/- 31 ms) underwent robotic LV lead placement after failed CS cannulation. Mean patient age was 71 +/- 12 years, LV ejection fraction (EF) was 12 +/- 6%, and LV end-diastolic diameter was 7.1 +/- 1.3 cm. Three patients had previous cardiac surgery, and five patients had a prior device implanted. RESULTS: Nineteen epicardial leads were successfully placed on the posterobasal surface of the LV. Intraoperative lead threshold was 1.0 +/- 0.5 V at 0.5 ms, R-wave was 18.6 +/- 8.6 mV, and impedance was 1,143 +/- 261 ohms at 0.5 V. Complications included an intraoperative LV injury and a postoperative pneumonia. Improvements in exercise tolerance (8 of 10 patients), EF (19 +/- 13%, p = 0.04), and QRS duration (152 +/- 21 ms, p = 0.006) have been noted at three to six months follow-up. Lead thresholds have remained unchanged (2.1 +/- 1.4 V at 0.5 ms, p = NS), and a significant drop in impedance (310 +/- 59 ohms, p < 0.001) has been measured. CONCLUSIONS: Robotic LV lead placement is an effective and novel technique which can be used for ventricular resynchronization therapy in patients with no other minimally invasive options for biventricular pacing.

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PubMed2002

Ventricular pacing or dual-chamber pacing for sinus-node dysfunction.

BACKGROUND: Dual-chamber (atrioventricular) and single-chamber (ventricular) pacing are alternative treatment approaches for sinus-node dysfunction that causes clinically significant bradycardia. However, it is unknown which type of pacing results in the better outcome. METHODS: We randomly assigned a total of 2010 patients with sinus-node dysfunction to dual-chamber pacing (1014 patients) or ventricular pacing (996 patients) and followed them for a median of 33.1 months. The primary end point was death from any cause or nonfatal stroke. Secondary end points included the composite of death, stroke, or hospitalization for heart failure; atrial fibrillation; heart-failure score; the pacemaker syndrome; and the quality of life. RESULTS: The incidence of the primary end point did not differ significantly between the dual-chamber group (21.5 percent) and the ventricular-paced group (23.0 percent, P=0.48). In patients assigned to dual-chamber pacing, the risk of atrial fibrillation was lower (hazard ratio, 0.79; 95 percent confidence interval, 0.66 to 0.94; P=0.008), and heart-failure scores were better (P<0.001). The differences in the rates of hospitalization for heart failure and of death, stroke, or hospitalization for heart failure were not significant in unadjusted analyses but became marginally significant in adjusted analyses. Dual-chamber pacing resulted in a small but measurable increase in the quality of life, as compared with ventricular pacing. CONCLUSIONS: In sinus-node dysfunction, dual-chamber pacing does not improve stroke-free survival, as compared with ventricular pacing. However, dual-chamber pacing reduces the risk of atrial fibrillation, reduces signs and symptoms of heart failure, and slightly improves the quality of life. Overall, dual-chamber pacing offers significant improvement as compared with ventricular pacing.

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