Complesso QRS Forze elettriche della depolarizzazione ventricolare Vettore 1 Setto: sx vs dx; post vs ant Vettore 2 Ventricoli: dx vs sx; Ant vs post Rilevanza di forze generate da parete libera di V sx
<b>FIGURE 9-14</b> Schematic representation of ventricular depolarization as two sequential vectors representing septal <b>(left)</b> and left ventricular free wall <b>(right)</b> activation. QRS waveforms generated by each stage of activation in leads V<sub>1</sub> and V<sub>6</sub> are shown.
Blocchi di Branca (BB) Il fascio di His si divide nelle branche sx e dx La branca sx si divide nell’emifascio anteriore e posteriore I ritardi (blocchi) di conduzione in questi fasci producono specifici pattern EKG
Criteri Diagnostici per BBD Durata QRS > 0.12 s BBD: depolarizzazione ritardata in V dx V sx: depolarizzazione normale; prima parte del QRS è normale V dx: diffusione depolarizzazione tramite tessuto di conduzione non specializzato forze vettoriali non contrastate Criteri Diagnostici per BBD Durata QRS > 0.12 s Onda secondaria R in V1 o V2 Onda S larga e scucchiaiata in I, V5-V6 Caratt. associate ST sottolivellato e onde T negative in precordiali dx
Blocco di Branca destro: eziologia Malattia reumatica Cor polmonare Ipertrofia ventr dx Miocardite / CMP Ischemia Miocardica Mal. Degener. Sistema di conduzione Embolia polmonare Mal. Congenite cardiache (difetti SIA)
BBD Criteri Diagnostici per BBD Durata QRS > 0.12 s Onda secondaria R in V1 o V2 Onda S larga e scucchiaiata in I, V5-V6 Caratt. associate ST sottolivellato e onde T negative in precordiali dx
BBS raramente presente senza cardiopatia organica frequente eziologia ischemica due vascolarizzazioni: ramo di IVA e ramo di coron. Dx malattia estesa direz. di depolarizzaz. del setto interventricolare: invertita Onde Q settali in precordiali sx … perse Criteri diagnostici: Durata QRS: > 0.12 s Onde R larghe: I, V5 e V6 Onde Q: assenti in V5-V6 Caratt. associate ST e onda T: discordanti a deflessione dominante in QRS Scarsa progressione vettore settale Deviaz. Assiale sx frequente
<b>FIGURE 9-46A</b> <b>A,</b> With uncomplicated left bundle branch block, early septal forces are directed to the left. Therefore, no Q waves will be seen in V<sub>5</sub> and V<sub>6</sub> <b>(right panel)</b>. <b>B,</b> With left bundle branch block complicated by anteroseptal infarction, early septal forces can be directed posteriorly and rightward <b>(left panel)</b>. Therefore, prominent Q waves may appear in V<sub>5</sub> and V<sub>6</sub> as a paradoxical marker of septal infarction <b>(right panel)</b>. <b>C,</b> Anterior wall infarction (involving septum) with left bundle branch block. Note the presence of QR complexes in leads I, aV<sub>l</sub>, V<sub>5</sub>, and V<sub>6</sub>. (<b>A</b> and <b>B</b> adapted from Dunn MI, Lipman BS: Lipman-Massie Clinical Electrocardiography. 8th ed. Chicago, Mosby-Year Book, 1989.)
<b>FIGURE 9-46B</b> <b>A,</b> With uncomplicated left bundle branch block, early septal forces are directed to the left. Therefore, no Q waves will be seen in V<sub>5</sub> and V<sub>6</sub> <b>(right panel)</b>. <b>B,</b> With left bundle branch block complicated by anteroseptal infarction, early septal forces can be directed posteriorly and rightward <b>(left panel)</b>. Therefore, prominent Q waves may appear in V<sub>5</sub> and V<sub>6</sub> as a paradoxical marker of septal infarction <b>(right panel)</b>. <b>C,</b> Anterior wall infarction (involving septum) with left bundle branch block. Note the presence of QR complexes in leads I, aV<sub>l</sub>, V<sub>5</sub>, and V<sub>6</sub>. (<b>A</b> and <b>B</b> adapted from Dunn MI, Lipman BS: Lipman-Massie Clinical Electrocardiography. 8th ed. Chicago, Mosby-Year Book, 1989.)
Criteri diagnostici: Durata QRS: > 0.12 s Onde R larghe: I, V5 e V6 Onde Q: assenti in V5-V6 Caratt. associate ST e onda T: discordanti a deflessione dominante in QRS Scarsa progressione vettore settale Deviaz. assiale sx frequente
<b>FIGURE 9-27</b> Comparison of typical QRS-T patterns in right bundle branch block (RBBB) and left bundle branch block (LBBB) with the normal pattern in leads V<sub>1</sub> and V<sub>6</sub>. Note the secondary T wave inversions (arrows) in leads with an rSR′ complex with RBBB and in leads with a wide R wave with LBBB. (From Goldberger AL: Clinical Electrocardiography: A Simplified Approach. 6th ed. St Louis, CV Mosby, 1999.)
Blocco trifascicolare BB dx EAS BAV I° grado
<b>FIGURE 9-7</b> Lead vectors for the three bipolar limb leads, the three augmented unipolar limb leads <b>(left),</b> and the six unipolar precordial leads <b>(right)</b>.
<b>FIGURE 9-8</b> The heart vector H and its projections on the lead axes of leads I and III. Voltages recorded in lead I will be positive and potentials in lead III will be negative.
<b>FIGURE 9-9</b> The hexaxial reference system composed of the lead axes of the six frontal plane leads. The lead axes of the six frontal plane leads have been rearranged so that their centers overlay one another. These axes divide the plane into 12 segments, each subtending 30 degrees. Positive ends of each axis are labeled with the name of the lead.
<b>FIGURE 9-17</b> Schematic representation of atrial depolarization <b>(diagram)</b> and P wave patterns associated with normal atrial activation <b>(left panel)</b> and with right <b>(middle panel)</b> and left <b>(right panel)</b> atrial abnormalities. (Modified from Park MK, Guntheroth WG: How to Read Pediatric ECGs. 3rd ed. St Louis, Mosby-Year Book, 1993.)
<b>FIGURE 9-18</b> Biatrial abnormality, with tall P waves in lead II (right atrial abnormality) and an abnormally large terminal negative component of the P wave in lead V<sub>1</sub> (left atrial abnormality). The P wave is also notched in lead V<sub>5</sub>.
<b>FIGURE 9-19</b> Left ventricular hypertrophy (LVH) increases the amplitude of electrical forces directed to the left and posteriorly. In addition, repolarization abnormalities can cause ST segment depression and T wave inversion in leads with a prominent R wave (formerly referred to as a “strain” pattern). Right ventricular hypertrophy (RVH) can shift the QRS vector to the right; this effect is usually associated with an R, RS, or qR complex in lead V<sub>1</sub>, especially when due to severe pressure overload. T wave inversions may be present in the right precordial leads. (From Goldberger AL: Clinical Electrocardiography: A Simplified Approach. 6th ed. St Louis, CV Mosby, 1999.)
<b>FIGURE 9-20</b> Marked left ventricular hypertrophy (LVH) pattern with prominent precordial lead QRS voltages. ST depression and T wave inversion can be seen with severe LVH in leads with a predominant R wave (compare with Fig. 9-21). Left atrial abnormality is also present.
<b>FIGURE 9-21</b> Left ventricular hypertrophy with prominent positive anterior T waves from a patient with severe aortic regurgitation. This pattern has been described with “diastolic overload” syndrome but has limited sensitivity and specificity. Serum potassium level was normal.
<b>TABLE 9-1</b> Location of Electrodes and Lead Connections for the Standard 12-Lead Electrocardiogram and Additional Leads
<b>TABLE 9-2</b> Normal Values for Durations of Electrocardiographic Waves and Intervals in Adults
<b>TABLE 9-3</b> Common Diagnostic Criteria for Left and Right Atrial Abnormalities
<b>TABLE 9-4</b> Common Diagnostic Criteria for Left Ventricular Hypertrophy
<b>TABLE 9-5</b> Common Diagnostic Criteria for Right Ventricular Hypertrophy
<b>TABLE 9-6</b> Common Diagnostic Criteria for Unifascicular Blocks
<b>TABLE 9-7</b> Common Diagnostic Criteria for Bundle Branch Blocks
<b>TABLE 9-8</b> Differential Diagnosis of Tall R Waves in V<sub>1</sub>/ V<sub>2</sub>
<b>TABLE 9-9</b> Differential Diagnosis of Noninfarction Q Waves (with Selected Examples)
<b>TABLE 9-10</b> Differential Diagnosis of ST Segment Elevation
<b>TABLE 9-11</b> Differential Diagnosis of Prominent T Wave Inversion
<b>TABLE 9-12</b> Causes of Low-Voltage QRS Complexes
<b>TABLE 9-13</b> Examples of Alternans Patterns in Electrocardiographic Diagnosis
<b>TABLE 9G-1</b> ACC/AHA Guidelines for Electrocardiography in Patients with Known Cardiovascular Disease or Dysfunction
<b>TABLE 9G-2</b> ACC/AHA Guidelines for Electrocardiography in Patients Suspected of Having or Who Are at Increased Risk for Cardiovascular Disease or Dysfunction
<b>TABLE 9G-3</b> ACC/AHA Guidelines for Electrocardiography in Patients with No Apparent or Suspected Heart Disease or Dysfunction