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Biomedical subjects

P Kułakowski

Publications and source records attributed to P Kułakowski.

16 recordsLinked to original sources
PubMed2001

Influence of mobile phones on accuracy of ECG interpretation algorithm in automated external defibrillator.

BACKGROUND: Automated External Defibrillators (AED) are a recommended tool for out-of-hospital emergency medical services. Mobile phones (GSM) are a potential source of electromagnetic interference which may cause failure of ECG interpretation and subsequent inappropriate action of AED's. METHODS: We evaluated the influence of 900 MHz GSM phones on the accuracy of automatic ECG interpretation with a GSM Mobile Station Tester with adjustable power and mode of transmission (Hewlett-Packard HP5515A), GSM phones (Alcatel, Ericsson, Nokia, Panasonic), ECG simulator (Metron) and four AEDs (Fore Runner-Hewlett-Packard, Heartstart 3000-Laerdal, Cardio-Aid 100-Artema, Heartstream XLT-Agilent). The protocol included 18 different ECG patterns, different ECG voltages, and different power and mode of transmission. RESULTS: The first stage of the protocol included minimal power of signal transmitted from GSM Mobile Station Tester and maximum power of GSM phone's signal--hence maximal potential interference to AED. The protocol was based on close direct contact between the GSM phone and the AED device. Regardless of the ECG pattern, with both 0.5 and 1.0 mV ECG voltage, and the GSM phone placed on various parts of AED device or at the patient cable, no failure of AED algorithm occurred. No detectable noise was seen at AED's ECG display. CONCLUSION: AEDs seems to be well protected against clinically significant failure caused by noise from 900 MHz GSM phones.

Electric Countershock↗
PubMed2001

QT interval dispersion in ventricular beats: a noninvasive marker of susceptibility to sustained ventricular arrhythmias.

Increased QT dispersion (QTd) calculated from sinus beats has been shown to identify patients prone to sustained VT. However, predictive accuracy of this parameter is limited. Electrophysiological properties of the myocardium may be altered by a premature ventricular beats, which is a well-established trigger for sustained VT. Therefore, the author hypothesised that QTd in spontaneous or paced ventricular beats may improve identification of patients with inducible sustained VT. In 28 consecutive patients (men, mean age 61 +/- 13 years) who underwent programmed ventricular stimulation, the values of QTd calculated in sinus and ventricular beats were compared between inducible and noninducible patients. The mean QTd values obtained using three different methods differed significantly, QTd in paced ventricular beats being the highest, QTd in spontaneous ventricular beats was intermediate, and QTd in sinus beats was the lowest (83.9 +/- 30 vs 63.0 +/- 29 ms vs 53.9 +/- 27 ms, P < 0.0001 and P < 0.004, respectively). In 13 (46%) patients sustained VT was induced. QTd values were significantly higher in inducible than noninducible patients (QTd sinus beats: 67.5 +/- 31 vs 42.1 +/- 11 ms, P = 0.02; QTd spontaneous ventricular beats: 79.3 +/- 35 vs 46.7 +/- 13 ms, P = 0.008, and QTd-paced ventricular beats: 104.8 +/- 32 vs 65.9 +/- 9 ms, P = 0.0009). The receiver operator characteristic curves showed that at a sensitivity level of 100%, the highest specificity for identification of inducible patients had QTd measured in paced ventricular beats (87%) followed by QTd in spontaneous ventricular beats (45%), and QTd in sinus beats (40%). In conclusion, (1) QTd in ventricular beats is greater than in sinus beats, and (2) QTd calculated from paced ventricular beats identifies patients with inducible sustained VT better than QTd measured during sinus rhythm.

Electrocardiography↗
PubMed2000

Susceptibility to neuromediated syncope after acute myocardial infarction.

BACKGROUND: Syncope after acute myocardial infarction (AMI) is a common clinical problem. It may be hypothesised that remodelling and neurohormonal changes following AMI may predispose to neuromediated syncope. DESIGN: To address this issue we prospectively evaluated the incidence of positive results of head-up tilt-table testing in 40 patients following AMI and 40 age and sex matched controls without a history of syncope. The mechanisms of tilt-induced changes in autonomic tone were assessed using spectral analysis of heart rate variability. The patients were followed-up for one year. RESULTS: Positive results of tilt-test occurred in 4 (10%) controls and 13 (33%) AMI patients (P = 0.01). No significant differences in sympathovagal interaction (assessed by a low frequency/high frequency ratio) were detected between the groups before tilting (2. 9 +/- 1.9 vs. 3.1 +/- 2.2; NS). However, dynamic changes of this parameter differed significantly during the first 5 symptomless minutes of the active phase of tilt-test. The ratio increased in the majority of controls (87%) and decreased in the majority of patients (62%) (P < 0.0001). During one year follow-up, syncope or presyncope occurred in 10 (25%) AMI patients but did not occur in any control subject (P < 0.001). The sensitivity, specificity and predictive accuracy of an early tilt-test after AMI for the prediction of syncope or presyncope was 70%, 80% and 78%, respectively. CONCLUSION: Patients after AMI are prone to neuromediated reactions. Sympathetic withdrawal seems to be the most likely mechanism of syncope. The role of tilt testing for identification of patients susceptible to syncope or presyncope after AMI needs further investigation.

Adrenergic beta-Antagonists↗
PubMed2000

Effects of intravenous amiodarone on ventricular refractoriness, intraventricular conduction, and ventricular tachycardia induction.

AIMS: Intravenous amiodarone has recently emerged as an important drug for the acute treatment of ventricular tachyarrhythmias. However, electrophysiological actions and the efficacy of the drug in the suppression of ventricular tachycardia inducibility have not yet been fully established. The present study was designed to address these issues. METHODS AND RESULTS: The study group consisted of 18 patients (all males, mean age 75 +/- 14 years), who underwent electrophysiological study due to a history of sustained ventricular tachyarrhythmia or syncope with non-sustained ventricular tachycardia detected on ambulatory ECG monitoring. The effects of 5 mg.kg(-1) or 10 mg.kg(-1) of intravenous amiodarone on (1) ventricular refractoriness (QTc interval, right ventricular effective refractory period and monophasic action potential duration), (2) intraventricular conduction (paced-QRS and signal-averaged QRS duration), and (3) ventricular tachycardia inducibility, were examined. The drug had no significant effect on ventricular refractoriness. However, a relatively small but significant slowing of intraventricular conduction was seen (paced-QRS duration: 182 +/- 27 ms vs 191 +/- 28 ms, P<0.0007; 183 +/- 32 ms vs 195 +/- 33 ms, P<0.0007; and 177 +/- 21 ms vs 192 +/- 24 ms, P<0.003, at the cycle lengths of 600, 500 and 400 ms, respectively). This effect was more evident during extrasystolic beats than during stable pacing (for example, at the cycle length of 600 ms, the magnitude of amiodarone-induced lengthening of QRS duration was 23.9 +/- 17.6 ms vs 9.7 +/- 7.2 ms, P<0.009, respectively). Intravenous amiodarone did not prevent induction of sustained ventricular tachycardia in any of five patients inducible at baseline. Of six patients with non-sustained ventricular tachycardia, five had sustained ventricular tachycardia or fibrillation induced after amiodarone infusion. CONCLUSION: Intravenous amiodarone does not prolong ventricular refractoriness, slows intraventricular conduction and may facilitate inducibility of sustained ventricular arrhythmias.

Aged↗
PubMed2000

Passive-fixation J-shaped versus straight leads in atrial position: comparison of efficacy and safety.

To compare the efficacy and safety of straight and J-shaped passive-fixation atrial leads we retrospectively analyzed the results of 100 consecutive implantations of atrial leads at one institution. There were seven cases of upgrades of VVIR to DDDR systems and in one case an active-fixation lead was chosen as a primary approach. These eight patients were excluded from the analysis. The final study group consisted of 92 cases (69 DDDR, 23 AAIR), 69 were J and 23 straight leads. The stimulation threshold, slew rate, impedance, P wave amplitude, and procedural time did not differ significantly between the two types of leads used. During the long-term follow-up of 6-53 months (30 +/- 11.9 months), replacements using active-fixation leads were required in two patients with straight leads and three patients with J leads (P = NS). In addition, one J lead showed signs of damage (impedance > 3,000 Ohm). Long-term follow-up values of the stimulation thresholds and P wave amplitudes did not differ between the groups (P = NS). Transesophageal echocardiography performed in 13 patients revealed a trend toward more distal placement of straight leads within the right atrial appendage. In conclusion, J-shaped leads do not seem to be superior to the straight leads for atrial implantations.

Adolescent↗
PubMed1996

Intravenous amiodarone is safe and seems to be effective in termination of paroxysmal supraventricular tachyarrhythmias.

BACKGROUND: Paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) leading to hemodynamic compromise are among the most common reasons for admission to the coronary care unit (CCU) and need prompt and efficient therapy. Direct current cardioversion is the therapy of choice, but if found contraindicated or unavailable some antiarrhythmic agents are usually given to restore sinus rhythm. Many of these drugs have obvious limitations, especially in patients with acute myocardial infarction and/or heart failure. HYPOTHESIS: The aim of the present study was to assess the safety and efficacy of intravenous amiodarone in the acute termination of PAF or PSVT refractory to other antiarrhythmic agents in a large group of patients consecutively admitted to our CCU. METHODS: In the present study, we evaluated the safety and efficacy of amiodarone given intravenously in 142 consecutive patients with PAF or PSVT lasting < 24 h. In 37% of patients no evidence of underlying heart disease which may have caused arrhythmias were defined. A median of two other antiarrhythmic agents given prior to the first amiodarone injection had been ineffective. RESULTS: Sinus rhythm was restored in 91 patients (64%) (65% in the PAF group and 61% in the PSVT group). The mean time to rhythm conversion was 5.5 +/- 6.1 h for patients with PAF and 1.2 +/- 1.2 h for patients with PSVT. The mean dose of amiodarone administered up to conversion was 340 +/- 220 mg for PAF and 220 +/- 105 mg for PSVT. Except for transient first-degree atrioventricular block in two patients, no adverse effects possibly related to amiodarone were observed (including proarrhythmia and incidence or aggravation of heart failure symptoms). CONCLUSION: Amiodarone given intravenously for acute termination of supraventricular tachyarrhythmias is completely safe and seems effective. The results of this study, which is the largest ever made, indicate a need of randomized, controlled trials for the ultimate assessment of the efficacy of amiodarone in this clinical setting.

Aged↗
PubMed1995

Exercise producing alterations in the signal-averaged electrocardiogram in patients after myocardial infarction.

Late potentials are considered to be a marker for regional slow conduction which might predispose to reentrant ventricular arrhythmias. Since these arrhythmias may be induced by ischaemia it may be speculated that exercise-induced myocardial ischaemia may trigger late potentials. Exercise testing was performed in 53 patients early after myocardial infarction and in 20 healthy controls. Typical 12 lead ECG and signal averaged ECG (SA-ECG) from 12 leads were recorded before and after exercise testing. Changes in filtered QRS (QRS) and low amplitude signal durations, and in the root mean square voltage of the last 40 ms of the QRS complex (RMS40) were analysed. Thirty patients developed ST changes, consistent with transient ischaemia, that persisted during the SA-ECG recording after exercise. There were significant differences between baseline SA-ECG and SA-ECG after exercise in patients with positive exercise tests (QRS, 102 +/- 15 ms vs 114 +/- 15 ms (P < 0.01). LAS, 36 +/- 12 ms vs 42 +/- 11 ms (P < 0.05), and RMS40, 29 +/- 14 microV vs 20 +/- 13 microV (P < 0.01). No differences were observed in SA-ECG parameters in either patients with negative exercise tests or in controls. During follow-up, four patients died suddenly; all four had positive exercise tests and in three of them late potentials were induced by exercise. We conclude, that in post-infarction patients with positive exercise tests SA-ECG parameters deteriorate after exercise. This suggests that exercise-induced ischaemia triggers development of late potentials.

Adolescent↗
PubMed1988

Late potentials in the acute phase of myocardial infarction indicate the risk of early ventricular fibrillation.

Late potentials occurring at the end of or after the QRS complex were recorded from the body surface by means of a high-gain ECG and the signal-averaging technique in 75 patients, within 24 h from the onset of symptoms of acute myocardial infarction. Late potentials were found in 20 patients (26.7%). Out of this group, eight (40%) developed ventricular fibrillation. There was only one incident of ventricular fibrillation among 55 patients without late potentials (1.8%, P less than 0.001). The three-month mortality after myocardial infarction was slightly higher in individuals with late potentials: 15% vs. 11.5%, but this difference was not statistically significant. We conclude that the presence of late potentials recorded in the acute phase of myocardial infarction indicates a risk of ventricular fibrillation, but this was not associated with an increased mortality rate during the three-month follow-up.

Action Potentials↗
PubMedDate not supplied

[The effect of work-related stress on the occurrence of increased blood pressure].

In 546 officials the arterial blood pressure was measured twice at the beginning and at the end of a working day, filling also an inquiry form. As hypertension systolic BP over 160 mm Hg (21.3 kPa) or more, and diastolic BP 96 mm Hg (12.7 kPa) or more were accepted. In 90 subjects (16.5%) above normal pressure values were found. Hypertension had been diagnosed previously in 50 subjects in this group (55.5%) but only 13 of them (26%) were treated systematically. Excessive stress of work was complained of by 62.6% of the subjects. Increased blood pressure was found significantly more frequently in the group perceiving excessive stress of work (19.9%) as compared to those not experiencing this stress (10.8%, p less than 0.1). In the group in managerial posts these proportions were 24.8% and 14.4% respectively (p less than 0.1). Blood pressure rise to abnormal levels during the working day occurred also significantly more frequently in the group experiencing it this was noted only in 1.6% of cases (p less than 0.5). The knowledge of own hypertension was very low in this group. These results indicate the necessity of increasing prophylactic measures in the form of greater frequency of control measurements of the blood pressure, better health education, and limitation of stress situations in working environment.

Adult↗