Cardiovascular response to exercise during atrial fibrillation and after conversion to sinus rhythm

Haemodynamic studies before and after electrical conversion of atrial fibrillation and flutter to sinus rhythm.

“…Large increases in cardiac output following the establishment of sinus rhythm are also reported by Halmos and Patterson (1965) and by Kahn et al (1964). Benchimol, Lowe, and Akre (1965) who studied eight patients before and after the conversion of atrial fibrillation to sinus rhythm also demonstrated that the improvement in cardiac function when in sinus rhythm was more evident during exercise. Morris et al (1964a) showed an average increase in cardiac output at rest of 34 per cent in 7 of 11 patients converted to sinus rhythm, while all five patients studied on exercise had an average increase in cardiac output of 17 per cent.…”

Doppler Evidence for Reduced Atrial Contribution to Left Ventricular Filling in Patients with a Dilated Cardiomyopathy and a 'B-Bump' on the Mitral Valve Echocardiogram

“…In the present study, transmitral early and late pulsed Doppler flow velocity signals were utilized to measure early diastolic filling (E), and late diastolic (atrial, A) contribution to left ventricular filling [1-8, 14, 15, 17-20]. Although various factors such as age, sample volume site [ 1,2,27] and left atrial pressure [3,6,15,29] may influence Dopp ler-derived transmitral flow velocity parameters, hemo dynamic information obtained by this technique has been favorably compared to that yielded from angiographic [7] or radionuclide studies [8], Previous studies have demonstrated that left atrial sys tole contributes importantly to optimal left ventricular performance [9][10][11][12]. In a series of experiments, Gessel [9] proved that a properly timed left atrial contraction is important in augmenting ventricular output in the healthy left ventricle.…”

“…Clinical indications for échocar diographie examination l Pulsed-wave Doppler echocardiography provides a method of measuring transmitral flow velocity patterns and, hence, of characterizing normal [1][2][3] and abnormal left ventricular filling [3][4][5], Analysis of these flow veloci ties provides a measure of left atrial volume contribution to left ventricular filling and cardiac output [1][2][3][4][5][6][7][8]. The hemodynamic importance of the properly timed left atrial contraction has been well documented in the normally functioning left ventricle at rest or during exercise [9][10][11]. However, there is conflicting published information as to whether atrial systole leads to better filling and to further augmentation of stroke volume in the compromised left ventricle [11][12][13][14][15][16].…”

Atrial fibrillation and hyperthyroidism: a new look at their relationship and therapy with lidoflazine

“…Therefore, there is no need to leave the hyperthyroid patient, with his disturbing symptoms of palpitations or atrial fibrillation with fast ventricular rate and decreased cardiac output and effort tolerance (Benchimol, Lowe and Akre, 1965;Bouma and May, 1967), until stable euthyroid state is obtained and hoping atrial fibrillation will spontaneously convert to sinus rhythm. Although propranolol (Howitt and Rowlands, 1966), guanethidine (Lee, Bronsky and Waldstein, 1962;Waldstein et al, 1964;Goldstein and Killip, 1965) and reserpine (Canary et al, 1957) have been shown to diminish palpitations in patients with hyperthyroidism, they do not convert atrial fibrillation to sinus rhythm, and a complete return to normal conditions of heart rate and cardiac output is not achieved.…”