Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Patent
1997-02-27
1998-09-01
Getzow, Scott M.
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
A61N 1365
Patent
active
057993505
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a blood flow velocity measurement device. Such a device is used for the measurement of blood flow velocity characteristics within the heart and large blood vessels especially for the purpose of control of the electrotherapy.
BACKGROUND OF THE INVENTION
Physiologic cardiac pacing is very important on temporary as well on permanent basis Temporary pacing is usually applied either after cardiac surgery or during myocardial infarction because of the transient conduction disturbance or arrhythmia. Patients in rest have significantly improved cardiac output when ventricular contraction is synchronous with atrial filling of ventricles. This is very important for faster recovery after surgery or after myocardial infarction. Furthermore, some arrhythmias like supraventricular tachycardias and extrasystolies may be prevented by means of physiologic pacing.
Patients with chronic conduction and rhythm disturbance have to receive a permanent implantable pacing system. They also have a significant contribution of atria to the hemodynamic benefit. There are two basic modes of physiologic cardiac pacing: sequential and synchronous. The sequential atrio-ventricular pacing is used to restore normal atrio-ventricular physiologic sequence. In this mode, an atrium and a ventricle are paced by twin stimuli separated by an appropriate physiologic interval. However the heart rate is controlled by the pacemaker program and does not vary according to the physiological nexus. The synchronous cardiac pacing approximates most closely to the normal cardiac rhythm. The spontaneous atrial electrogram (P-wave) is sensed by an electrode usually in contact with the atrial endocardium and this is used to trigger the ventricle after an appropriate preset delay. Because the atrial rhythm is paced by our natural pacemaker sinus-atrial node, the frequency varies naturally according to the body workload. Therefore the P-wave synchronous ventricular cardiac pacing is considered to be the most physiologic rate-responsive pacing. p Accordingly, our invention disclosed in U.S. Pat. No. 5,243,976 and in U.S. Pat. No. 5,316,001 enables new method of physiologic cardiac pacing. The aim of our invention is to provide a pacemaker which will, in normal atrial rhythm, act in a synchronous mode (VDD) and maintain atrio-ventricular synchronism, yet with the need for implantation of a single lead. In carrying out the invention, the blood flow within the heart is monitored with a device for the blood flow velocity measurement mounted on a cardiac pacing lead. Particularly the flow waveform through the tricuspid valve is used for synchronization and control of ventricular cardiac pacing. The early rapid diastolic filling wave (E-wave) as well as the late atrial diastolic filling wave (A-wave) are detected and their parameters are measured. The ventricular pacing is synchronized with the A-wave. The device provides sensors for rate responsive ventricular pacing and reliable means for atrial fibrillation detection. It is another object to provide continuous monitoring of the right ventricular filling dynamics in order to estimate the ventricular muscle performance and to automatically reprogram the maximum tracking rate in such a way as to prevent the angina pectoris and the high-rate induced myocardial ischemia. Our system is capable to detect single premature ventricular contractions, as well as it is capable to discriminate the sinus tachycardia from the pathologic tachycardia. It provides confirmation of the ventricular capture and detection of right ventricular failure.
Another system, disclosed in our U.S. Pat. No. 5,318,595 monitors the ventricular filling and actually regulates the pattern of ventricular filling waveform by means of the A-V interval adjustment for the purpose of hemodynamics optimisation.
It is very important for proper function of these inventions to utilise the low power, long term reliable and accurate method of blood flow measurement, suitable for implementation in implantable device
REFERENCES:
patent: 5174289 (1992-12-01), Cohen
patent: 5243976 (1993-09-01), Ferek-Petric et al.
patent: 5318595 (1994-06-01), Ferek-Petric et al.
Breyer Branko
Ferek-Petric Bozidar
Getzow Scott M.
Pacesetter AB
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