11. The illustration shows an ECG at the lower part and a pressure curve at the...

Transcribed Image Text:

11. The illustration shows an ECG at the lower part and a pressure curve at the upper part. Why is the mechanical action (contraction of the heart with pressure development) later than the ECG (the pressure increases only after the QRS complex) Choose the right answer the conduction of the action potential is very low the contraction can only start when the action potential has reached the whole heart muscle the mechanical contraction needs more time than the electrical excitation - - - 120 100- 80 PRESSURE 60 (mmHg) 40 20 O 0 Aortic Pressure Left Atrial Pressure a-wave Atrial Systole 0.1 Closing of AV Valves Iso- Rapid Vol. Ejection Con- tract 0.2 R Opening of Aortic Valve S 0.3 0.4 TIME (sec) Closing of Aortic Valve T Reduced Iso- Rapid Ejection Vol. Filling Relax Left Ventricular Pressure. 0.5 Opening of AV Valves 0.6 Reduced Filling 0.7 Electrocardiogram 0.8 FIG 4-5. Diagram showing a representative pressure pulse from aorta, left ventricle, and left atrium. An ECG also is shown. See text for discussion. 11. The illustration shows an ECG at the lower part and a pressure curve at the upper part. Why is the mechanical action (contraction of the heart with pressure development) later than the ECG (the pressure increases only after the QRS complex) Choose the right answer the conduction of the action potential is very low the contraction can only start when the action potential has reached the whole heart muscle the mechanical contraction needs more time than the electrical excitation - - - 120 100- 80 PRESSURE 60 (mmHg) 40 20 O 0 Aortic Pressure Left Atrial Pressure a-wave Atrial Systole 0.1 Closing of AV Valves Iso- Rapid Vol. Ejection Con- tract 0.2 R Opening of Aortic Valve S 0.3 0.4 TIME (sec) Closing of Aortic Valve T Reduced Iso- Rapid Ejection Vol. Filling Relax Left Ventricular Pressure. 0.5 Opening of AV Valves 0.6 Reduced Filling 0.7 Electrocardiogram 0.8 FIG 4-5. Diagram showing a representative pressure pulse from aorta, left ventricle, and left atrium. An ECG also is shown. See text for discussion.

Answer rating: 100% (QA)

Answer Explaination The phases of the cardiac action potentia... View the full answer