Evaluation of continuous monitoring of stroke volume and cardiac output in patients supported by an intra-aortic balloon pump.

BACKGROUND: Currently available minimally invasive devices cannot provide continuous determination of stroke volume (SV) or cardiac output (CO) in patients supported with an intra-aortic balloon pump (IABP). Our aim was to evaluate the accuracy of Dat-con™ monitor for continuous SV and CO determination in such patients. METHODS: SV (SVdat-con) and CO (COdat-con) were determined by Dat-con™ monitor in 35 patients supported by IABP, at baseline and after 103 therapeutic interventions. Echocardiography was used to measure SV (SVecho) and CO (COecho) from velocity time integral and cross-sectional area of left ventricular outflow tract. Monitored and echocardiographic values were compared using Bland-Altman's statistics. RESULTS: Bias in baseline SVdat-con compared to SVecho was 0.2 mL, with 1.96 limits of agreement (SD) of ±4.8 mL and with percentage error of 11%. Bias of baseline COdat-con compared to COecho was 0.03 l/min, with 1.96 SD of ±0.435 l/min with percentage error of 10.9%. After therapeutic interventions, bias of SVdat-con compared to SVecho was -0.3 mL, with 1.96 SD of ±4.8 mL and with percentage error of 10.5%. Agreement for SV changes was >95% (exclusion zone: changes <10%). Bias of COdat-con compared to COecho after therapeutic interventions was -0.03 L/min, with 1.96 SD of ±0.45 L/min. CONCLUSION: The accuracy and trending of continuous determination of SV and CO with Dat-con™ monitor in patients supported by IABP is equivalent to echocardiography.

Cardiogenic shock following a single therapeutic oral dose of verapamil.

Cardiogenic shock and apnoea appeared in a 78-year-old woman with a history of biventricular heart failure, following ingestion of a single 80 mg verapamil tablet. She was resuscitated with artificial ventilation, dobutamine, norepinephrine and calcium gluconate. Toxicological analysis revealed unexpectedly high plasma verapamil concentration, which was attributed to the patient's liver failure. In patients with advanced heart failure a single oral therapeutic dose of verapamil may have a severe toxic effect.

Spectral components of heart rate variability determined by wavelet analysis.

Spectral components of heart rate variability (HRV) are determined in the time-frequency domain using a wavelet transform. Based on the finer estimation of low-frequency content enabled by the logarithmic resolution of the wavelet transform, corrections of spectral intervals, already defined by Fourier and model based methods, are proposed. The characteristic peaks between 0.0095 and 0.6 Hz are traced in time and four spectral intervals are defined, I (0.0095-0.021 Hz), II (0.021-0.052 Hz), III (0.052-0.145 Hz) and IV (0.145-0.6 Hz), within which peaks are located for all subjects included. These intervals are shown to be invariant regardless of the age and the state of the system. We also show that the frequency and power of the spectral components are related to age, AMI and particularly to type II diabetes mellitus.

Recurrent sepsis and seronegative arthritis in a patient with a selective IgG3 deficiency.

In a sixty-one-year-old patient with chronic polyarthritis, two life-threatening septic events were observed over a period of 6 months. The patient also had a selective IgG3 deficiency. The susceptibility to infection and chronic polyarthritis observed in this patient were very likely a consequence of the selective IgG3 deficiency.

Ventricular septal rupture following blunt chest trauma after a long delay: a case report.

We observed a patient with ventricular septal rupture occurring 33 days after a blunt chest trauma. The presumed mechanism was interventricular septal dissection and formation of a pseudoaneurysm that ruptured after a delay. Echocardiography enabled a non-invasive diagnosis and follow-up of the patient.

Correlation between QTc interval duration and left ventricular systolic dysfunction in patients with acute myocardial infarction.

QTc interval and left ventricular regional wall motion abnormality score (WMS) were assessed in 61 consecutive patients with 4-day-old acute myocardial infarction (AMI). There were 45 men and 16 women, aged 60.6 +/- 8.7 years; 24 had anterior wall AMI and 37 had inferior wall AMI. Twenty-nine patients received thrombolytic treatment, which was presumably successful in 19. The longest QTc interval from a standard 12-lead electrocardiogram, corrected by Bazett's formula, was considered for the study. The WMS was evaluated echocardiographically. The authors found a statistically significant correlation between WMS and QTc interval duration; the correlation was stronger in patients with anterior AMI (r = .9, P < .001) than in those with inferior AMI (r = .66, P < .001). The WMS and QTc values were significantly lower in patients with successful thrombolytic treatment compared to those with unsuccessful thrombolysis (P < .003 and P < .002, respectively). The authors could demonstrate no significant correlation between serum potassium concentration and the QTc interval. In patients with anterior AMI, QTc interval duration might represent an additional marker of left ventricular systolic dysfunction. It could also be used as an additional noninvasive criterion of coronary artery reperfusion in patients with AMI.

Value of signal averaged electrocardiogram for prediction of successful coronary artery thrombolysis.

In 60 patients with acute myocardial infarction (AMI) treated with brief i.v. infusion of streptokinase, signal averaged surface ECG as well as 24-hour ECG were recorded within the first 6 hours after admission and 5 to 10 days later. Results obtained from a group with presumed reperfusion (early plasma creatine kinase activity peak, cessation of pain, decrease in ST segment elevations, the appearance of "reperfusion arrhythmias"), were compared to those from patients with no reperfusion. The first recording showed a higher incidence of ventricular late potentials (VLP) in the group with reperfusion (77% vs. 44%, p less than 0.01), and a smaller difference in the incidence of complex ventricular arrhythmias (89% vs. 68%, p = 0.06). In the period between the two recordings, the incidence of VLP decreased in higher proportion in the same group (p less than 0.025). The incidence of complex ventricular arrhythmias was similar in both groups in the second recording. The authors conclude that complex ventricular arrhythmias following successful thrombolytic therapy occur together with "reperfusion VLPs", which are a better marker for successful thrombolysis in patients with AMI than a high grade of ventricular ectopic activity.

Romano-Ward syndrome: case report, family study and signal averaged electrocardiogram.

A family with the Romano-Ward syndrome is described. A 28-year-old woman had episodes of syncope due to self-terminating ventricular tachycardia torsades de pointes. During lidocaine treatment she developed a sustained ventricular tachycardia and cardiopulmonary resuscitation was necessary. Propranolol reduced ventricular ectopic activity, but the QTc interval remained prolonged. A "threshold" in QT duration for the generation of complex ventricular arrhythmias was observed in the patient. There were no late ventricular potentials noted in the signal averaged ECG in the patient and in members of her family.