Electrocardiography

1 Electrocardiography

FIGURE 1-1 This ECG reveals sinus arrhythmia. For this diagnosis the P-wave axis and morphology have to be normal with a gradual change in the P-P interval. The difference between the shortest and longest P-P intervals must be >10%.

FIGURE 1-2 An ECG obtained from a 28-year-old male college basketball player. It displays sinus bradycardia with early repolarization (normal variant).

FIGURE 1-3 A, This ECG was obtained on a routine physical examination in a 50-year-old male. The ECG displays sinus rhythm and findings consistent with dextrocardia. Note the positive P waves and upright QRS in lead aV_R and the reverse in leads I and aV_L. Also note that the R-wave progression in the chest leads is reversed. B, A subsequent ECG was obtained for this patient. In this ECG the chest leads are rearranged onto the right precordium, correcting the abnormal R-wave progression. If the above information was not known, one would then comment on left and right arm lead reversal in their interpretation.

FIGURE 1-4 Normal sinus rhythm, left atrial abnormality, LVH, and prolonged QT interval (487 ms). The criteria for LAE include a notched P wave with duration ≥ 0.12 s in inferior leads (P mitrale) and terminal downward deflection of the P wave in V₁ with negative amplitude of 1 mm and duration of 0.04 ms.

FIGURE 1-5 Note the following findings on this ECG: normal sinus rhythm, sinus arrhythmia, RAD, LAE, RAE, RVH with ST-segment and/or T-wave abnormality secondary to hypertrophy. Lead V₂ and V₃ are reversed. Finally, an atrial premature complex is present (asterisk).

FIGURE 1-6 This ECG reveals sinus rhythm with a nonspecific IVCD. The criteria for IVCD are QRS ≥ 110 ms and morphology not meeting criteria for either LBBB or RBBB. Some of the common causes include conduction system disease, antiarrhythmic drug toxicity, hyperkalemia, WPW syndrome, and hypothermia.

FIGURE 1-7 This ECG was obtained in an asymptomatic 84-year-old male. It reveals sinus rhythm, LAE, complete RBBB, and LAFB. Criteria for LAFB include frontal plane axis of −45° to −90°, qR pattern in lead aV_L, R peak time in lead aV_L of 45 msec or more, and QRS duration less than 120 msec in absence of a RBBB.

FIGURE 1-8 Sinus rhythm with LAFB. Criteria for LAFB are axis between −45° and −90°, qR complex in lead aV_L, R peak time in lead aV_L of 45 msec or more, and QRS duration less than 120 msec. In addition, other reasons for LAD such as LVH or inferior infarct should be absent. Remember in the presence of LAFB, voltage criteria for LVH using the R-wave amplitude in lead aV_L in isolation is not applicable.

FIGURE 1-9 This ECG was obtained in a 65-year-old female with cardiomyopathy. It demonstrates sinus rhythm and complete LBBB. For a diagnosis of complete LBBB the following criteria should be present: QRS duration > 120 ms; delayed intrinsicoid deflection in the left-sided precordial leads (V₅ and V₆); broad monophasic R waves in leads I, aV_L, V₅, and V₆; QS or rS complex in lead V₁; and absent septal Q waves in the left-sided leads.

FIGURE 1-10 A 34-year-old male with exertional shortness of breath. The ECG reveals sinus bradycardia (rate 50 bpm), voltage criteria for LVH with pseudo Q waves in leads I and aV_L. An echocardiogram confirmed the diagnosis of HCM.

FIGURE 1-11 A, This ECG was obtained in a 29-year-old male with a history of HCM with a significant outflow tract gradient of 90 mm Hg. The ECG reveals sinus rhythm, LAE, and LVH with ST-T abnormalities due to hypertrophy. B, The same patient, after failing medical therapy, underwent surgical septal resection. Postoperatively he developed an IVCD resembling LBBB.

FIGURE 1-12 A, A 56-year-old male presented to the emergency department promptly after the onset of precordial chest pain, nausea, and shortness of breath. An ECG was obtained that revealed normal sinus rhythm with low voltage in the frontal leads.Figure 1-12—cont’dB, This ECG was obtained 30 minutes after onset of pain. There are hyperacute T waves (arrows) in the precordial leads, suggesting acute anterolateral myocardial injury. ST-segment elevation is present in leads I and aV_L. Reciprocal changes of ST-segment depression and T-wave inversion are noted inferiorly. C, A third ECG was obtained as the patient was being prepared for the cardiac catheterization laboratory. ST-segment elevation (arrows) and anterior Q waves developed indicative of acute anterior and lateral MI/injury. Note reciprocal ST-segment depression (arrows with asterisks) in the inferior leads.

FIGURE 1-13 This ECG reveals sinus rhythm with acute inferolateral injury. ST-segment elevation is present in leads II, III, aV_F, V₅, and V₆. Reciprocal ST-segment depression is present in the high lateral leads, I and aV_L. Diagnostic Q waves consistent with acute inferior infarction are present in lead III but borderline in aV_F.

FIGURE 1-14 This ECG reveals sinus rhythm, first-degree AV block, and an atrial-sensed and ventricular-paced rhythm. An acute AMI is evident on this ECG. Note the primary ST-segment and T-wave changes best seen in V₄ and V₅.

FIGURE 1-15 This ECG reveals sinus rhythm with an interpolated PVC and an age-indeterminate inferior wall MI. An interpolated PVC occurs most often when the sinus rate is slow and it does not disturb the sinus rhythm.

FIGURE 1-16 This 69-year-old male presented with sudden onset of chest pain to the emergency department. The ECG reveals sinus rhythm, RBBB, with Q waves and ST-segment elevation in leads V₁ to V₄, suggesting acute anteroseptal STEMI. Note RBBB does not interfere with the diagnosis of AMI as LBBB does.

FIGURE 1-17 This ECG was obtained from a 78-year-old male with a history of MI 10 years ago. He is followed in a heart failure clinic. The ECG reveals normal sinus rhythm, LAE, borderline LAD, and an old anterior and lateral MI. There is persistent ST-segment elevation anteriorly, suggesting ventricular aneurysm.

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Tags: Cardiovascular Imaging Review Expert Consult

Dec 26, 2015 | Posted by admin in CARDIOVASCULAR IMAGING | Comments Off

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