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Delectable deductive diagnosis: Lean children of fat parents
CARDIAC CONUNDRUM
Delectable deductive diagnosis: Lean children of fat parents George Nikolic´, FRACP, FACC
T
he patient was a 75-year-old woman with chronic ischemic/hypertensive heart disease, and a permanent pacemaker had been inserted 2 years previously for a ‘‘bifascicular block.’’ The 12lead electrocardiogram (ECG) shown in Figure 1 was performed in the emergency room (ER) after a transient ischemic attack (TIA). The patient was asymptomatic by then. Because of the TIA, her ECG received more scrutiny than was perhaps warranted. It was felt that the ventricular lead of the pacemaker was failing to capture the ventricle. A chest x-ray and routine tests were noncontributory. The ECG was brought to my office for an urgent report. I was pleased to report a sequential pacemaker rhythm, right-bundle branch block (RBBB), and right-axis deviation (RAD), probably a left posterior hemiblock (LPHB). My pleasure
was short-lived. Fifteen minutes later, an indignant ER consultant rang me to say that ‘‘even he knew my report was wrong,’’ and that I had not addressed the question of ventricular capture at all. It did not improve matters that I responded with my usual question in this situation, ‘‘Do you believe me or your own eyes?’’ He slammed down the receiver and I had to come down to the ER to placate him. I should have been less laconic and reported fusion complexes throughout. The inference of the invisible RBBB and LPHB is based on the knowledge of what ‘‘pure’’ paced complexes are like, i.e., they have left-bundle branch block (LBBB) morphology, with left-axis deviation (LAD) in the frontal plane. A normalized QRS and axis in this paced rhythm imply fusion of RBBB and LBBB morphologies.
Fig 1 Admission ECG, as discussed in text. From the Intensive Care Unit, Canberra Hospital, Canberra, Australian Capital Territory, Australia. Corresponding author: G. Nikolic´, FRACP, FACC, 11 Birdwood St., Hughes, Australian Capital Territory 2605, Australia. E-mail: geonik@pcug. org.au 0147-9563/$ – see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.hrtlng.2009.08.001
176
www.heartandlung.org
MARCH/APRIL 2010
HEART & LUNG
Nikolic´
Delectable deductive diagnosis
Fig 2 Sinus tachycardia with RBBB and RAD attributable to presumptive LPHB. Repolarization changes are consistent with ischemia.
A normalized axis means the fusion of beats with the RAD and LAD, respectively. There was also a history of ‘‘bifascicular block.’’ In electrocardiography, fat parents often have lean children! This was indeed the case. I was vindicated, but not forgiven. The patient became agitated and tachycardic, and another ECG was recorded (Fig 2). The trace then showed the expected RBBB + LPHB combination, perhaps attributable to an old septal infarction manifest as qR in V1. This is not likely in view of the preserved ‘‘septal’’ q in V6. In assessing the electrical axis of the limb leads, only the initial 0.06 second (or sec) of the QRS is considered. In this trace, the narrow q in the inferior leads is quickly replaced by the inferiorly directed R-wave. In Figure 1, the negative deflection in the inferior leads (broader but shallow in lead 2) follows the pacing spike and documents the initial capture by the pacemaker. The later QRS is ‘‘fused.’’ The 0.06 sec axis is approximately 30 .
HEART & LUNG VOL. 39, NO. 2
As always, the LPHB cannot be diagnosed with certainty unless the RVH is excluded on otherthan-ECG grounds. Both qRV1 and RAD are cardinal signs of RVH. To complicate matters further, either hemiblock can inscribe Q-waves in V1 or V2. So how are we to know? One has to reach for the ultrasound findings, and in this case, all they revealed was concentric left-ventricular hypertrophy. Another lesson bears mentioning. In hospital reporting, style should be sacrificed to clarity and humor should be discouraged, if not discarded altogether. The ‘‘priceless privilege of expressing unfettered opinions in congenial company’’ from Richard Gordon’s Doctor in the Nest1 is now a thing of the past.
REFERENCE 1. Gordon R. Doctor in the nest. Harmondsworth: Penguin Books, Ltd; 1982. p. 53.
www.heartandlung.org
177
Delectable deductive diagnosis: Lean children of fat parents George Nikolic´, FRACP, FACC
T
he patient was a 75-year-old woman with chronic ischemic/hypertensive heart disease, and a permanent pacemaker had been inserted 2 years previously for a ‘‘bifascicular block.’’ The 12lead electrocardiogram (ECG) shown in Figure 1 was performed in the emergency room (ER) after a transient ischemic attack (TIA). The patient was asymptomatic by then. Because of the TIA, her ECG received more scrutiny than was perhaps warranted. It was felt that the ventricular lead of the pacemaker was failing to capture the ventricle. A chest x-ray and routine tests were noncontributory. The ECG was brought to my office for an urgent report. I was pleased to report a sequential pacemaker rhythm, right-bundle branch block (RBBB), and right-axis deviation (RAD), probably a left posterior hemiblock (LPHB). My pleasure
was short-lived. Fifteen minutes later, an indignant ER consultant rang me to say that ‘‘even he knew my report was wrong,’’ and that I had not addressed the question of ventricular capture at all. It did not improve matters that I responded with my usual question in this situation, ‘‘Do you believe me or your own eyes?’’ He slammed down the receiver and I had to come down to the ER to placate him. I should have been less laconic and reported fusion complexes throughout. The inference of the invisible RBBB and LPHB is based on the knowledge of what ‘‘pure’’ paced complexes are like, i.e., they have left-bundle branch block (LBBB) morphology, with left-axis deviation (LAD) in the frontal plane. A normalized QRS and axis in this paced rhythm imply fusion of RBBB and LBBB morphologies.
Fig 1 Admission ECG, as discussed in text. From the Intensive Care Unit, Canberra Hospital, Canberra, Australian Capital Territory, Australia. Corresponding author: G. Nikolic´, FRACP, FACC, 11 Birdwood St., Hughes, Australian Capital Territory 2605, Australia. E-mail: geonik@pcug. org.au 0147-9563/$ – see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.hrtlng.2009.08.001
176
www.heartandlung.org
MARCH/APRIL 2010
HEART & LUNG
Nikolic´
Delectable deductive diagnosis
Fig 2 Sinus tachycardia with RBBB and RAD attributable to presumptive LPHB. Repolarization changes are consistent with ischemia.
A normalized axis means the fusion of beats with the RAD and LAD, respectively. There was also a history of ‘‘bifascicular block.’’ In electrocardiography, fat parents often have lean children! This was indeed the case. I was vindicated, but not forgiven. The patient became agitated and tachycardic, and another ECG was recorded (Fig 2). The trace then showed the expected RBBB + LPHB combination, perhaps attributable to an old septal infarction manifest as qR in V1. This is not likely in view of the preserved ‘‘septal’’ q in V6. In assessing the electrical axis of the limb leads, only the initial 0.06 second (or sec) of the QRS is considered. In this trace, the narrow q in the inferior leads is quickly replaced by the inferiorly directed R-wave. In Figure 1, the negative deflection in the inferior leads (broader but shallow in lead 2) follows the pacing spike and documents the initial capture by the pacemaker. The later QRS is ‘‘fused.’’ The 0.06 sec axis is approximately 30 .
HEART & LUNG VOL. 39, NO. 2
As always, the LPHB cannot be diagnosed with certainty unless the RVH is excluded on otherthan-ECG grounds. Both qRV1 and RAD are cardinal signs of RVH. To complicate matters further, either hemiblock can inscribe Q-waves in V1 or V2. So how are we to know? One has to reach for the ultrasound findings, and in this case, all they revealed was concentric left-ventricular hypertrophy. Another lesson bears mentioning. In hospital reporting, style should be sacrificed to clarity and humor should be discouraged, if not discarded altogether. The ‘‘priceless privilege of expressing unfettered opinions in congenial company’’ from Richard Gordon’s Doctor in the Nest1 is now a thing of the past.
REFERENCE 1. Gordon R. Doctor in the nest. Harmondsworth: Penguin Books, Ltd; 1982. p. 53.
www.heartandlung.org
177