Slowing of the heart by paired pulse pacemaking

Chardack, William M.; Gage, Andrew A.; Dean, David C.

doi:10.1016/0002-9149(64)90082-7

Cited by 55 publications

(8 citation statements)

References 2 publications

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“…An increase in contractile force, measured with a myocardial strain-gauge arch, was demonstrated in open-chest experi ments on the intact dog (57,58). Ross et al (65) have shown that when mean aortic pressure, stroke volume, and effective contraction rates are held con stant, a change from single to paired stimulation markedly improved the per formance of the left ventricle, as evidenced by a shortening of the ejection time; by an increase in left ventricular dp/ dt, stroke power, and peak ejection rates; and sometimes by a fall in ventricular end-diastolic pressure.…”

Section: Electrophysiologymentioning

confidence: 89%

“…This mode of stimulation has been re ferred to as "coupled pacing' . ' and ber of effective ventricular contractions per minute (57,61,62) . Among the advantages of the coupled pacing mode are that the normal temporal rela tionships between atrial and ventricular contractions are retained if the un derlying rhythm is sinus in origin, and that the first ventricular depolariza tion wave spreads over normal pathways.…”

Section: Electrophysiologymentioning

confidence: 99%

“…Among the advantages of the coupled pacing mode are that the normal temporal rela tionships between atrial and ventricular contractions are retained if the un derlying rhythm is sinus in origin, and that the first ventricular depolariza tion wave spreads over normal pathways. It is also possible to slow the ven tricular rate by delivering pairs of stimuli to the atrium (57). If the second of these reaches the atrioventricular conduction system while it is still refrac tory, the ventricular rate may be reduced without inducing pairs of ventricu lar depolarizations.…”

Section: Electrophysiologymentioning

confidence: 99%

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Heart

Braunwald¹

1966

Annu. Rev. Physiol.

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Section: Electrophysiologymentioning

confidence: 89%

Section: Electrophysiologymentioning

confidence: 99%

Section: Electrophysiologymentioning

confidence: 99%

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Heart

Braunwald¹

1966

Annu. Rev. Physiol.

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“…On the basis of experience from treatment of ventricular tachycardias in patients with atrioventricular block, pacing has been attempted against ventricular tachycardia in patients with no such block (Sowton et al, 1964;Hartel et al, 1966). In paired-pulse pacemaking (Chardack et al, 1964), the rate of ventricular contractions can be slowed down by paired electrical stimulations separated by an interval of 150 to 250 msec. Contraction will only follow after the first stimulus.…”

Section: Discussionmentioning

confidence: 99%

“…Once more the sinus rhythm returned by pacing, and now the pacemaker was switched off immediately. However, ventricular tachycardia reappeared after two hours, and subsequent conversion attempts with a pacemaker were unsuccessful, even with paired pulse pacing (Chardack, Gage, and Dean, 1964).…”

Section: Case Reportmentioning

confidence: 99%

Recurrent ventricular tachycardia.

Salokannel¹,

Waris²,

Kreus³

1969

Heart

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Ventricular tachycardia is a dangerous form of arrhythmia, and is usually a manifestation of serious heart disease, either acute ischaemia, severe heart failure, myocarditis, or sometimes drug intoxication, especially digitalis. Treatment is only rarely based on aetiology. The most effective therapy has been found to be electrical conversion (Lown et al., 1963;Castellanos, Lemberg, and Fonseca, 1965;Waris, Kreus, and Salokannel, 1967). However, defibrillation does not prevent relapses, and therefore it is often compulsory to repeat cardioversions and to use antiarrhythmic agents to retain sinus rhythm. The purpose of the present paper is to report a case of recurrent ventricular tachycardia, and to show that the key problem is how to prevent new attacks after successful electrical conversion. Case ReportA shopkeeper, aged 56, was first examined in 1964 in the Department of Medicine, University of Oulu. Two years earlier he had had a myocardial infarction, but he recovered and was able to resume work. He was admitted to our hospital for ventricular tachycardia of three days' duration despite treatment with quinidine and procainamide. On admission he was in a poor condition, being cyanotic, hypotensive, and in heart failure. The electrocardiogram revealed ventricular tachycardia, with a rate of 180. He was given quinidine sulphate (2-4 g. a day) and four doses of procainamide, 1000 mg. each, intramuscularly or intravenously. Since tachycardia persisted for 10 days after admission, a non-synchronized direct current countershock was given. This was the first defibrillation in our hospital. A single 100 wattsecond shock converted the heart to sinus rhythm. The electrocardiogram revealed sinus rhythm, the characteristics of inferior wall infarction, and ischaemic anterior wall lesions. After defibrillation he was given digoxin 0-25 mg. twice daily, quinidine bisulphate 0 4 gr. twice daily, and prednisolone 5 mg. twice daily. Twelve days after defibrillation he had the first relapse ( Fig.). Intravenous procainamide and carotid sinus massage failed, but the first shock (100 watt-seconds) again restored sinus rhythm. During the following five days there were two relapses, both converted to sinus rhythm by defibrillation.There were nine more attacks of ventricular tachycardia during the next 11 months, and each one was converted to sinius rhythm by a single 100 watt-second D-C shock. During the next year the patient had one attack in January and another in November. The following year the first relapse occurred in January.Apart from a few weeks in the summer, the patient was then permanently in hospital because of recurring attacks of ventricular tachycardia and poor condition. He died at the end of October 1966.In all, this patient was defibrillated for 47 attacks of ventricular tachycardia. The first shock of 100 wattseconds resulted in sinus rhythm in 40 attacks. On one occasion a second and on another a third 100 wattsecond discharge converted ventricular tachycardia to sinus rhythm. Four times a 200 watt-second disc...

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