Sudden death in epilepsy: An experimental animal model O. Mameli, M.A. Caria, A. Pintus, G. Padua, S. Mameli  Seizure - European Journal of Epilepsy  Volume 15, Issue 5, Pages 275-287 (July 2006) DOI: 10.1016/j.seizure.2006.02.007 Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 1 Traces refer to simultaneous recordings of spontaneous electrical activity of hypothalamic neurons (1), electrothalamogram (ETG; 2), vagal nerve fibers (3) and electrocardiogram (4) in a survived animal. (A) Basal conditions. (B) Sixty minutes after the activation of cardioarrhythmogenic triggers at hypothalamic and mesencephalic levels. Paroxysmal hypothalamic activity (B1) is synchronized to ETG activity (B2) vagal nerve firing (B3), as well as to specific ECG events such as: impairment of A-V conduction, ventricular escapes and sinus-atria blocks (B4). Horizontal calibrations: traces 1–2 (800ms/div); traces 3–4 (1.2s). Vertical calibrations: trace 1 (500μV); trace 2 (200μV); trace 3 (80μV); trace 4 (0.25mV). Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 2 Diagram in A shows the correlation analysis between the electrical activity of epileptic foci (HEF-MEF) and the spontaneous firing of vagal nerve fibers (MUAV). Diagram in B shows the correlation between MUAV and ECG impairments. Both diagrams refer to an animal of the survived group. Y-axis for HEF-MEF in A refers to the total number of paroxysmal episodes, and X-axis for MUAV to the total number of vagal nerve spikes. Y-axis for MUAV in B refers to the total number of vagal nerve spikes and X-axis for ECG impairments, to the total number of different pathological events. Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 3 Traces refer to simultaneous recordings of ETG (A–D trace 1) and ECG (A–D trace 2) in basal conditions (A), 20min (B), 30min (C) and 60min (D), following cardioarrhythmogenic triggers activation at hypothalamic and mesencephalic level in an animal of the survived group. Electrocardiographic recordings show a significant voltage increase of atria and ventricular complexes (B–D), sinus bradyarrhythmias (C) and (D) second degree blocks (Mobiz 1). Horizontal calibration: 0.5s (all traces). Vertical calibrations: ETG (200μV); ECG (1mV). Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 4 Traces refer to simultaneous recordings of ETG (A–C trace 1) and ECG (A–C trace 2) in basal conditions (A), 30min (B), and 60min (C), following cardioarrhythmogenic triggers activation at hypothalamic and mesencephalic level in an animal of the survived group. Electrocardiographic recordings show a significant voltage increase of atria and ventricular complexes (B and C). Calibrations: as in Fig. 3. Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 5 Tables in A show mean±S.D. relative to the main metabolic, cardiovascular and respiratory parameters determined in basal conditions and during interictal and ictal activity in animals of the deceased group. For sodium (Na+), potassium (K+), bicarbonate (HCO3−) and pH, values are expressed as mEq/L. For hemoglobin (Hb) values are expressed in g/100ml, for pO2 and pCO2 pressures in mmHg and for heart rate (HR) in beats/min. Arterial systolic (ASP), diastolic (ADP) and pulmonary artery pressures (PAP) are expressed in mmHg. Multiunit vagal nerve firing (MUAV) and cardioarrhythmogenic triggers activity (HEF-MEF) are expressed as number of spikes/s. Statistical significance of differences (ANOVA) between basal conditions, interictal and ictal activity are also shown. Diagram in B shows the correlation analysis between the electrical activity of vagal nerve fibres (MUAV) and blood potassium concentration (K+) during ictal activity. Y-axis for MUAV refers to total number of vagal nerve spikes and X-axis to potassium concentration (mEq/L). Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 6 Specimens of pulmonary artery pressures recordings (mmHg) in an animal of the deceased group. (A) basal conditions, (B) 20min and (C) 30min after the induction of the hypothalamic and mesencephalic cardioarrhythmogenic triggers. PA refers to pulmonary artery pressures min/max values, while in parenthesis are shown the mean values. Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 7 Hematoxylin–eosin histological preparations of lung tissue sample of a deceased animal. In (A) is appreciable a perivessel oedema in the sub-interstitial space of arterial vessels (4×). (B) Abundant intraluminal mucous secretion within the bronchial tree with an oedematous infiltration in the alveolar and peribronchial spaces (10×). (C) Abundant intraluminal mucous secretion within the bronchial lumen (10×). Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 8 Histograms showing hemodynamic and hemogas parameters along with the statistical significance of differences in surviving and deceased animals observed in basal conditions, during interictal and ictal activities. HR: heart rate (beat/min); ASP: arterial systolic pressure (mmHg); ADP: arterial diastolic pressure (mmHg); PAP: pulmonary arterial pressure (mmHg); MUA: multiunit vagal nerve activity (spike/sec); HEF-MEF: cardioarrythmogenic foci (spike/sec); Na+: sodium (mEq/l); K+: potassium (mEq/l); HCO3−: bicarbonate (mEq/l); pO2 and pCO2 (partial gases pressures (mmHg); Hb: haemoglobin (g% ml). t test: paired t-test. Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions

Figure 9 Histograms showing the percentage of ECG alterations along with the statistical significance in surviving and deceased animals during ictal activity. SAB: sinus-atria blocks; AVB: atria-ventricular blocks; BB: bundle blocks; SVEB: supra-ventricular ectopic beats; VEB: ventricular ectopic beats; ST: S-T impairments; T: T wave impairments. χ2: chi square test. Seizure - European Journal of Epilepsy 2006 15, 275-287DOI: (10.1016/j.seizure.2006.02.007) Copyright © 2006 British Epilepsy Association Terms and Conditions