Abstract: An implantable atrial defibrillator applies cardioverting electrical energy to the atria of a human heart in need of cardioversion and thereafter paces the heart in a demand mode. The atrial defibrillator includes a first detector for detecting atrial activity of the heart, an atrial fibrillation detector responsive to the atrial activity detected by the first detector for determining when the atria of the heart are in need of cardioversion, and a cardiovertor responsive to the atrial fibrillation detector for applying the cardioverting electrical energy to the atria of the heart when the atria are in need of cardioversion.

Abstract: An implantable automatic atrial defibrillator powered by a depletable battery power source conserves battery power for extending the predicted life of the defibrillator by intermittently detecting for atrial fibrillation. The atrial defibrillator includes a real time clock which, at spaced apart predetermined times, causes heart activity data to be stored in a memory. Thereafter, a normally deactivated atrial fibrillation detector is activated for processing the stored data to detect for atrial fibrillation.

Abstract: A post-surgical cardioverting system and method applies cardioverting electrical energy to the atria of the heart of a post-surgical heart patient. The system includes a first lead including a first elongated electrode having a proximal end and a distal end, a second lead including a second elongated electrode having a proximal end and a distal end, and sutures for releasably anchoring the distal ends of the first and second electrodes to the pericardium and disposing the first and second electrodes along the pericardium overlying the right and left atria respectively. A non-implantable cardiovertor is coupled to the first and second leads for applying the cardioverting electrical energy to the first and second electrodes. When cardioversion is no longer required, the first and second leads may be pulled out of the patient's chest.

Abstract: An implantable atrial defibrillator and method provides cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for detecting R waves of the heart, a second detector for detecting T waves of the heart, and a third detector for detecting atrial activity of the heart. An atrial fibrillation detector is responsive to the third detector for determining when the atria of the heart are in need of cardioversion. A cardioverting stage applies the cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion, after the second detector detects a T wave, and in timed relation to an R wave detected by the first detector after the detected T wave is completed.

Abstract: An atrial defibrillator reliably detects a depolarization activation wave of the heart and delivers cardioverting electrical energy to the atria of the heart in synchronism with a detected depolarization activation wave. The atrial defibrillator includes a first sensor for producing a first electrical output having a duration substantially equal to the duration of the depolarization activation wave sensed between a first pair of spaced apart locations of the heart. The atrial defibrillator further includes a second sensor for producing a second electrical output having a duration substantially equal to the duration of the depolarization activation wave sensed between a second pair of spaced apart locations of the heart. The spacing between the second pair of locations is greater than the spacing between the first pair of locations.

Abstract: An implantable atrial defibrillator provides cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for detecting atrial activity of the heart and an atrial fibrillation detector responsive to the first detector for determining when the atria of the heart are in need of cardioversion. The atrial defibrillator further includes a pacing output circuit responsive to the atrial fibrillation detector for pacing the ventricles of the heart at a pacing rate when the atria of the heart are in need of cardioversion and a cardioverter stage for applying the cardioverting electrical energy to the atria of the heart after the pacing output circuit has paced the ventricles for a predetermined number of cardiac cycles. The pacing output circuit stabilizes the cardiac rate of the heart prior to the application of the cardioverting electrical energy.

Abstract: An implantable atrial defibrillator provides cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for detecting ventricular activations of the heart, a second detector for detecting atrial activity of the heart, and an atrial fibrillation detector responsive to the second detector for determining when the atria of the heart are in need of cardioversion. The atrial defibrillator further includes a cardioverter for applying the cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion, and a timer delay stage responsive to the first detector for causing the cardioverter to apply the cardioverting electrical energy to the atria of the heart a predetermined delay time after the first detector detects one of the ventricular activations and before the T wave of the heart immediately following the one of the ventricular activations.

Abstract: An implantable atrial defibrillator applies cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for sensing atrial activity of the heart, an atrial fibrillation detector responsive to the first detector for determining when the atria of the heart are in need of cardioversion and a second detector for detecting ventricular activations of the heart. The atrial defibrillator further includes a cardioverter for applying cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion and is responsive to the second detector for applying the cardioverting electrical energy to the atria of the heart in predetermined time relation to a detected ventricular activation. The detection of atrial activity of the heart is interrupted when a ventricular activation of the heart is detected by the second detector.

Abstract: An implantable atrial defibrillator applies cardioverting electrical energy to the atria of a human heart in need of cardioversion and thereafter gradually returns the cardiac rate of the heart to a normal cardiac rate. The atrial defibrillator includes a first detector for detecting atrial activity of the heart, and an atrial fibrillation detector, responsive to said first detector, for determining when the atria of the heart are in need of cardioversion. The atrial defibrillator further includes a cardioverter responsive to the atrial fibrillation detector for applying the cardioverting electrical energy to the atria of the heart when the atria are in need of cardioversion, and a pacing output for pacing the ventricles of the heart at a decreasing cardiac rate from a base rate to a final rate lower than the base rate after the atria of the heart are successfully cardioverted.

Abstract: A pulse generator for use in implantable atrial defibrillator provides cardiovertinq electrical energy to the atria of a heart through at least one lead having a pair of electrodes associated with the atria of the heart. The pulse generator includes a depletable, low voltage, power source such as a battery. A charging circuit coupled to the battery includes a flyback transformer for converting the battery voltage to low duty cycle pulsating high voltage electrical energy to store the high voltage electrical energy in a storage capacitor coupled to the charging circuit. A crosspoint switch selectively couples the storage capacitor to the electrodes for applying a portion of the stored electrical energy to the atria of the heart for cardioverting the atria of the heart.

Abstract: An implantable atrial defibrillator provides cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for detecting ventricular activations of the heart, a second detector for detecting atrial activity of the heart, and an atrial fibrillation detector responsive to the second detector for determining when the atria of the heart are in need of cardioversion. The atrial defibrillator also includes a cardioverting stage for applying the cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion and when the time between immediately successive ventricular activations is greater than a preselected minimum time interval.

Abstract: A post-surgical cardioverting system and method applies cardioverting electrical energy to the atria of the heart of a post-surgical heart patient. The system includes a first lead including a first elongated electrode having a proximal end and a distal end, a second lead including a second elongated electrode having a proximal end and a distal end, and sutures for releasably anchoring the distal ends of the first and second electrodes to the pericardium and disposing the first and second electrodes along the pericardium overlying the right and left atria respectively. A non-implantable cardiovertor is coupled to the first and second leads for applying the cardioverting electrical energy to the first and second electrodes. When cardioversion is no longer required, the first and second leads may be pulled out of the patient's chest.