Cardiac sequelae in Brooklyn after the September 11 terrorist attacks.

BACKGROUND: Terrorism, such as the attacks on the World Trade Center (WTC) on September 11, 2001, result in higher stress-related disorders, especially in those persons in close proximity. HYPOTHESIS: Cardiac events resulting from the September 11, 2001 tragedy have not been detailed near the WTC. METHODS: Patients admitted to the Telemetry and Coronary Care Units at New York Methodist Hospital 4 miles from the WTC 60 days prior to and after the September 11 attacks were analyzed. In all, 1,653 admissions were reviewed: 427 records pre 9/11/2001 and 422, 393, and 411 records in the post-9/11/2001, pre-9/11/2000, and post-9/11/2000 data sets, respectively. Patients were categorized based on diagnosis: acute myocardial infarction (MI), unstable angina (UA), tachyarrhythmia (TA), and others (including syncope and congestive heart failure). RESULTS: There was a significant difference in the proportion of the various cardiac diagnoses post 9/11/01 (p = 0.008 by chi-square analysis). Compared with pre 9/11/2001, there were significantly more patients with acute MI (15.5 vs. 11.2%) and TA (19.9 vs. 13.6%) but fewer with UA (39.6 vs. 47.3%) after the terrorist attacks. The distribution of cardiac events during a similar period of time in 2000 revealed no such pattern. CONCLUSIONS: There was a significant increase in acute MI and TA and a smaller increase in UA after the September 11 attacks. The difference did not appear to be due to temporal variation. It appears that stress likely contributed to an increase in TA by itself or with ischemia, resulting in progression of UA to acute MI.

Feasibility of dual-chamber (DDD) pacing via a single-pass (VDD) pacing lead employing a floating atrial ring (dipole): case series, future considerations, and refinements.

The objective of this study was to assess the feasibility of DDD pacing from a standard single-pass VDD pacemaker system. Over the past 2 decades significant advances have been made in the development of single-pass VDD pacing systems. These have been shown in long-term prospective studies to effectively preserve atrioventricular (AV)synchrony in patients with AV block and normal sinus node function. What remains problematic is the development of a single-pass pacing system capable of DDD pacing. Such a lead configuration would be useful in those patients with peripheral venous anomalies and in younger patients with congenital anomalies, which may require lead revisions in the future. In addition, with the increased use of resynchronization (biventricular pacing) therapy, the availability of a reliable single-pass lead will minimize operative time, enhance patient safety, and minimize the amount of hardware within the heart. The feasibility of DDD pacing via a Medtronic Capsure VDD-2 (Model #5038) pacing lead was evaluated. Twenty patients who presented with AV block and normal sinus node function were recruited for this study. Atrial pacing thresholds and sensitivities were assessed intraoperatively in the supine position with various respiratory maneuvers. Five patients who agreed to participate in long-term follow-up received a dual-chamber generator and were evaluated periodically over a 12-month period. Mean atrial sensitivity was 2.35 +/- 0.83 mV at the time of implantation. Effective atrial stimulation was possible in all patients at the time of implantation (mean stimulation threshold 3.08 +/- 1.04 V at 0.5 ms [bipolar], 3.34 +/- 0.95 V at 0.5 ms [unipolar]). Five of the 20 patients received a Kappa KDR701 generator, and atrial electrical properties were followed up over a 1-year period. There was no significant change in atrial pacing threshold or incidence of phrenic nerve stimulation over the 1-year follow-up. A standard single-pass VDD pacing lead system was capable of DDD pacing intraoperatively and during long-term follow-up. Despite higher than usual thresholds via the atrial dipole, pacemaker telemetry revealed < 10% use of atrial pacing dipole over a 12-month period, which would minimally deplete the pacemaker's battery. In addition, the telemetry confirmed appropriate sensing and pacing of the atrial dipole throughout the study period. At this time such systems can serve as back-up DDD pacing systems with further refinements required to optimize atrial thresholds in all patients.

Profound thrombocytopenia associated with tirofiban: case report and review of literature.

Platelet glycoprotein (GP)IIb/IIIa inhibitors prevent fibrinogen binding and platelet aggregation. Inhibition of platelet activity at the injured coronary plaque is a target for novel therapeutic strategies. They decrease ischemic complications associated with non-ST-segment elevation acute coronary syndromes and percutaneous coronary intervention. Thrombocytopenia is a serious complication well described with the use of the prototype GP IIb/IIIa inhibitor abciximab. Its association with other agents of this class has been underemphasized. It is important to monitor platelet counts closely after initiation of GP IIb/IIIa inhibitor therapy, not only for abciximab, but also for small molecule inhibitors such as eptifibatide and tirofiban. Monitoring of platelet counts at 2 to 6 hours and 24 hours will detect most cases of acute thrombocytopenia. Adverse events may be prevented by prompt discontinuation of GP IIb/IIIa inhibitor therapy. The authors present a case of profound thrombocytopenia after the administration of tirofiban in the treatment of a patient with an acute coronary syndrome.

Adenosine-sensitive wide-complex tachycardia: an uncommon variant of idiopathic fascicular ventricular tachycardia--a case report.

Most wide-complex tachycardias encountered in the emergency department (ED) are ventricular in origin, most commonly associated with structural heart disease. Ventricular tachyarrhythmias range in severity from life-threatening rhythms (eg, ventricular fibrillation and hemodynamically compromising ventricular tachycardia [VT]) to idiopathic forms of VT, which have a benign clinical course and a more favorable prognosis. The authors present the case of a 34-year-old woman who presented to the ED, with a wide-complex tachycardia with a right-bundle-branch block (RBBB) morphology and a right inferior axis, which was terminated with adenosine. The patient was previously misdiagnosed as suffering from a paroxysmal supraventricular tachycardia (SVT), which was unresponsive to beta-blocker therapy. Although the tachycardia responded to adenosine, suggestive of an SVT, the patient was referred to the arrhythmia service, where further work-up revealed an uncommon form of an idiopathic VT, originating from the left anterior fascicle. The authors discuss the unique electrocardiographic and electrophysiologic properties and useful diagnostic maneuvers required to properly identify this form of VT.

Correction of AV-nodal block in a 27-year-old man with severe obstructive sleep apnea--a case report.

A 27-year-old morbidly obese man diagnosed with severe obstructive sleep apnea (OSA) and experiencing significant ventricular asystoles at times exceeding 8 seconds, during polysomnography. The bradyarrhythmias were successfully corrected with the application of a nasal continuous positive airway pressure (CPAP) mask. Follow-up 24-hour ambulatory Holter monitoring without the aid of a nasal CPAP mask and repeat polysomnography with a CPAP mask after several weeks of continuous CPAP therapy during sleep revealed no evidence of ventricular asystole, despite no change in the patient's body mass index. We discuss several mechanisms explaining the findings in this particular patient.

Effects of angiotensin-converting enzyme inhibitor therapy on QT dispersion post acute myocardial infarction.

The aim of this study was to determine the effect of an angiotensin-converting enzyme inhibitor (ACEI), initiated within 24 hours of an acute myocardial infarction (AMI), on the QT dispersion (QTd). ACEIs have proven beneficial in improving left ventricular remodeling, following an AMI while contributing to a reduction in sudden cardiac death (SCD). A prolonged QTd is a marker of electrical instability predisposing to ventricular arrhythmias and SCD. No one has looked at the effects on the QTd of ACEI therapy initiated within 24 hours of an AMI. The study included 239 consecutive patients who presented with an AMI between January 1, 1998 and December 31, 1998. A total of 105 patients had never been treated with an ACEI, and 51 patients were started on enalapril within 24 hours of presentation. Patient demographics were similar in both groups. All patients were treated with aspirin and beta-blocker therapy. A baseline QTd was determined and recalculated on days 3-4 and 6-7 following the AMI. There was no significant difference in the baseline QTd, heart rate, QTc(min), and QTc(max) between the two groups. On days 3-4 the QTd in the treatment group (A) was 39.2 +/- 19.4 ms, as opposed to 84.4 +/- 31.2 ms in the control group (B) (P = 1.0E-06). This reduction in QTd was accounted for by a significant difference in the QTc(max). The QTd shortened in both groups on days 6-7 with a QTd of 30.0 +/- 17.5 in group A and a QTd of 54.1 +/- 26.3 in group B (P = 1.0E-05). There was a significant difference in ejection fraction (EF) between the two groups with the ACEI treated group exhibiting a lower EF, (0.403 (A), 0.494 (B), P < 0.043). The mean dose of enalapril was 6.45 mg daily in the treatment group. ACEIs have been previously shown to reduce the QTd after two months of therapy following an AMI. This study shows that the beneficial effects of ACEI occur early following administration of the drug. The authors speculate that the reduction in SCD conferred by ACEI therapy may be attributed to its effect on reducing the degree of ventricular dispersion of repolarization following a myocardial infarction.

Inappropriate mode switching in a dual chamber pacemaker due to oversensing of a high frequency signal from a conductor/ring discontinuity (loose set screw).

Two unusual cases are reported of pacemaker oversensing of the impedance pulse by the atrial channel attributed to a loose set screw.