Electrocardiographic impacts of lung resection

Effect of lung resection on electrocardiography

BACKGROUND

Post-operative changes in electrocardiography (ECG) after lung surgery have been investigated in prior researches. We have limited data about benign physiologic changes in ECG after lung surgery, specifically after lung resection. The aim of our study was to investigate relationship in between lung resection with minimally invasive robotic or video-assisted thoracoscopic surgery (VATS) and its effect on ECG after lung resection.

METHODS

After exclusion criteria had been applied, a total of 133 patients were enrolled in the present study. Operational information such as amount of resected segment and side of resection was recorded. Lung resections were divided into two groups. One group included surgeries with lung resections <3 segments and other group included surgeries with segmentectomy ≥3 segments. Pre-operative and postoperative (in between 2nd and 3rd months) ECG data of the patients were compared. The location of resected segments as left-sided and right-sided resections were noted to compare the ECG changes for sub-analysis.

RESULTS

Among 133 patients, 101 patients were male (75.9%). There was no significant difference between parameters including ventricular rate, P wave, QRS wave and T wave axis in degrees, PR, QRS, QT and QTc durations, Tpe interval, ratio of Tpe interval to QT and QTc interval and fQRSTa. There was significant difference between before and after resection in terms of degree of QRS axis (before resection =37.3 ± 52.7 vs. after resection = 26.2 ± 55.7, P = .026). Sub-analysis regarding to amount of resected segments, there was no significant difference identified in terms of QRS axis in degrees between before and after resection for patients who underwent lung resection <3 segments (p = .885). However, there was significant difference in QRS axis in degrees for patients who underwent lung resection ≥3 segments (before resection = 47.3 ± 57.5 vs. after resection = 23.7 ± 66.2, P = .010). There was significant rightward axial change after left-sided lung resections (before resection =32.0 ± 52.4 vs. after resection = 49.4 ± 47.1, P = .005) and leftward axial change after right-sided lung resection (before resection = 41.7 ± 53.0 vs. after resection = 7.1 ± 55.2, P < .001).

CONCLUSION

Understanding and recognition of possible ECG changes are crucial during post-operative follow-up of the patients who underwent lung resection. These changes might be benign changes, which are related to anatomical and geometrical changes within thoracic cavity.

Elective lung resection increases spatial QRS-T angle and QTc interval

BACKGROUND

Lung resection changes intra-thoracic anatomy, which may affect electrocardiographic results. While postoperative cardiac arrhythmias have been recognized after lung resection, no study has documented changes in vectorcardiographic variables in patients undergoing this surgery. The purpose of this study was to analyse changes in spatial QRS-T angle (spQRS-T) and corrected QT interval (QTc) after lung resection.

METHODS

Adult patients undergoing elective lung resection under general anaesthesia were studied. The patients were allocated into four groups: those undergoing (1) left lobectomy (LL); (2) left pneumonectomy (LP); (3) right lobectomy (RL); and (4) right pneumonectomy (RP). The spQRS-T angle and QTc interval were measured one day before surgery (baseline) and 24, 48 and 72 h after surgery.

RESULTS

Seventy-one adult patients (47 men and 24 women) aged 47-80 (65 ± 7) years were studied. In the study group as a whole, lung resection was associated with significant increases in spQRS-T (p < 0.001) and QTc (p < 0.05 at 24 and 48 h and p < 0.01 at 72 h). The greatest changes were noted in patients undergoing LP. Postoperative atrial fibrillation (AF) was noted in 6.4% of patients studied, in whom the widest spQRS-T angle and the most prolonged QTc intervals were also noted.

CONCLUSIONS

Lung resection widens the spQRS-T angle and prolongs the QTc interval, especially in patients undergoing LP. While postoperative AF was a relatively rare complication after lung resection in this study, it was associated with the widest spQRS-T angles and most prolonged QTc intervals.

Cardiac structural and functional profile of patients with delayed QRS transition zone and sudden cardiac death

AIMS

Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has been recently associated with increased risk of sudden cardiac death (SCD), but the underlying mechanisms are unknown. We correlated echocardiographic findings with ECG and clinical characteristics to investigate how alterations in cardiac structure and function contribute to this risk marker.

METHODS AND RESULTS

From the ongoing population-based Oregon Sudden Unexpected Death Study (catchment population ∼1 million), SCD cases with prior ECG available (n = 627) were compared with controls (n = 801). Subjects with delayed transition at V5 or later were identified, and clinical and echocardiographic patterns associated with delayed transition were analysed. Delayed transition was present in 31% of the SCD cases and 17% of the controls. These subjects were older and more likely to have cardiovascular risk factors and history of myocardial infarction. Delayed transition was associated with increased left ventricular (LV) mass (122.7 ± 40.2 vs. 102.9 ± 33.7 g/m2; P < 0.001), larger LV diameter (53.3 ± 10.4 vs. 49.2 ± 8.0 mm; P < 0.001), and lower LV ejection fraction (LVEF) (46.4 ± 15.7 vs. 55.6 ± 12.5%; P < 0.001). In multivariate analysis, delayed transition was independently associated with myocardial infarction, reduced LVEF, and LV hypertrophy. The association between delayed transition and SCD was independent of the LVEF (OR 1.57; 95% CI 1.04-2.38; P = 0.032).

CONCLUSION

The underpinnings of delayed QRS transition zone extend beyond previous myocardial infarction and reduced LVEF. Since the association with sudden death is independent of these factors, this novel marker of myocardial electrical remodelling should be explored as a potential risk predictor of SCD.

Acute "Pseudoischemic" ECG Abnormalities after Right Pneumonectomy

New onset of electrocardiographic (ECG) abnormalities can occur after lung surgery due to the changes in the position of structures and organs in the chest cavity. The most common heart rhythm disorder is atrial fibrillation. So-called “pseudoischemic” ECG changes that mimic classic ECG signs of acute myocardial ischemia are also often noticed. We report the case of a 68-year-old male, with no prior cardiovascular disease, who underwent extensive surgical resection for lung cancer. On a second postoperative day, clinical and electrocardiographic signs of acute myocardial ischemia occurred. According to clinical course, diagnostic procedures, and therapeutic response, we excluded acute coronary syndrome. We concluded that physical lesion of the pericardium, caused by extended pneumonectomy with resection of the pericardium, provoked the symptoms and ECG signs that mimic acute coronary syndrome. Our final diagnosis was postpericardiotomy syndrome after extended pneumonectomy and further treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) was recommended. It is necessary to consider possibility that nature of ECG changes after extended pneumonectomy could be “pseudoischemic.”

Electrocardiographic changes after lung resection: Case report and brief review

The incidence of acute coronary syndrome after a lung resection is less, especially in an asymptomatic patient. However, arrhythmias are very commonly encountered which can be benign or may require anti-arrhythmic agents thereby increasing stay postoperatively in the Intensive Care Unit. We encountered unexpected ST-T changes after a left upper lobectomy under general anesthesia in a 60-year-old lady in the immediate postoperative period that made us to review the literature for electrocardiographic abnormalities after lung resection surgeries.