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C Gottfridsson

Publications and source records attributed to C Gottfridsson.

7 recordsLinked to original sources
PubMed1998

Full ventricular capture indicated by the QT interval function.

UNLABELLED: The atrioventricular (AV) interval is critical in dual chamber (DDD) pacing in patients with hypertrophic obstructive cardiomyopathy (HOCM) to obtain full ventricular capture (FVC) with maximal reduction of the left ventricular (LV) outflow gradient and optimal LV diastolic filling. We studied the relationship of FVC, fusion, spontaneous AV conduction, and the QT interval. METHODS: 11 patients with various cardiac diseases and stable AV conduction received a QT sensing Diamond, Vitatron, DDD pacemaker. Software was downloaded into the pacemaker. In the DDD pacing mode, with the QT interval measured from the ventricular pacing stimulus to the end of the T wave, the AV interval was shortened from 400 ms, in 20-ms steps, to 90 ms. At 90 ms the stimulation rate was increased by 30 beats/min and the AV interval was increased stepwise. FVC and fusion was examined on the surface ECG. RESULTS: At 400 ms interval, spontaneous AV conduction inhibited the pacemaker. Shortening the AV interval resulted in pacing with a short QT interval. Further reduction of the AV interval resulted in a longer QT interval up to a point where the QT interval became stable. This point, the bending point in the plot of measured QT interval versus shortened AV intervals, coincided with the point of FVC. The relation of the QT-AV interval plot and the point of fusion was comparable when lengthening the AV interval at a 30 beats/min faster stimulation rate. CONCLUSION: The bending point in the QT interval versus AV interval plots showed a good correlation with the FVC and fusion points observed on ECG. The results suggest that automatic discrimination between fusion and full capture using QT interval measurements may be feasible.

Aged↗
PubMed1995

Tolerance and effects of almokalant, a new selective Ik blocking agent, on ventricular repolarization and on sino-atrial and atrioventricular nodal function in the heart: a study in healthy, male volunteers utilizing transesophageal atrial stimulation.

Almokalant, (4-(3-ethyl(3-propylsulfinyl)propyl)amino)-2-hydroxy-propoxy)- benzonitrile), is a newly developed Ik channel blocker that exhibits pure class III effects. Using a noninvasive approach with transesophageal atrial stimulation (TAS), we wished to identify the dose of almokalant, given as an intravenous bolus infusion, that prolonged ventricular repolarization in the healthy human heart to an extent of potential clinical interest. Furthermore, we defined the electrophysiological effects of this dose on the heart, as well as the pharmacokinetics, safety, and tolerance throughout a wide dosing range. In the titration part, increasing doses were given to identify the dose that produced a reproducible QTend prolongation of approximately 20%. This dose (12.8 mumol) was then given in a placebo-controlled, double-blind, cross-over fashion. In the double-blind part, almokalant significantly prolonged the QTend intervals during sinus rhythm and during TAS at 100 beats/min and increased the effective refractory period of the atria (AERP). There was no alteration in either the cardiac conduction (PQ and QRS), or blood pressure (BP) sinus node function, or the ERP of the atrioventricular (AV) node. Therefore, almokalant exhibited pure class III effects with no signs of beta-blockade or unwanted hemodynamic effects. The plasma concentration-time curve showed a biexponential decrease with a terminal half-life (t1/2) of approximately 3 h. There was a large interindividual variation in the plasma concentration at the end of infusion, Cmax. This variability diminished considerably 60 min after infusion, and the pharmacokinetic characteristics studied appeared to be proportional to the dose. The drug was well tolerated, and the only side effect noted was a brief metallic taste after a dose of 25.6 mumol. Corresponding to high plasma peak values, T-wave morphology changes of short duration were observed, sometimes with the development of pronounced, biphasic T waves.

Adult↗
PubMed1991

Early treatment with thrombolysis and beta-blockade in suspected acute myocardial infarction: results from the TEAHAT Study.

Independent trials of early administration of beta-blockers and thrombolytic agents have shown beneficial effects on both short- and long-term prognoses in acute myocardial infarction (AMI). The effects of a combination of the two strategies have not been thoroughly documented. Three hundred and fifty-two patients, of less than 75 years of age, with chest pain indicative of AMI, and onset less than 2 h and 45 min before first examination, were randomized to treatment with rt-PA or placebo. All patients without contraindication were given intravenous metoprolol 15 mg acutely and then 200 mg orally daily. Treatment was started either at the prehospital stage or in hospital. Thirty-seven per cent of patients had contraindications to beta-blockade, the most frequent of which were heart rate less than 60 beats min-1 and hypotension. The remaining 63% were given intravenous beta-blockade. No side-effects of metoprolol, alone or in combination with rt-PA, were observed during the prehospital phase. Overall, toleration of the treatment was good. Reduction in enzymatically estimated infarct size by rt-PA was more pronounced in patients who were also treated with metoprolol (41%, P less than 0.001) than in those with contraindications to beta-blockade (15%, NS). Patients who were also treated with metoprolol also had a lower incidence of Q-wave infarctions, congestive heart failure and ventricular fibrillation than those who were not given intravenous beta-blockade. In conclusion, toleration of intravenous administration of rt-PA and metoprolol was good, and this was also the case in the prehospital phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗